计算机论文中英文翻译
外文翻译--计算机
外文原文computerThe modern world of high technology could not have come about except for the development of the computer. Different types and sizes of computers find uses throughout society in the storage and handling of data, from secret governmental files to banking transactions to private household accounts. Computers have opened up a new era in manufacturing through the techniques of automation, and they have enhanced modern communication systems. They are essential tools in almost every field of research and applied technology, from constructing models of the universe to producing tomorrow’s weather reports, and technique use has in itself opened up new areas of conjecture. Database services and computer networks make available a great variety of information sources. The same advanced techniques also make the invasions of privacy and restricted information sources possible, and computer crime has become one of the many risks that society must face if it is to enjoy the benefits of modern technology.A computer is an electronic device that can receive a set of instructions, or program, and then carry out this program by performing calculations on numerical data or by compiling and correlating other forms of information. The type of computers are mainly inclusive of Microcomputer, Minicomputer, Mainframe Computer and Supercomputer, etc. Microminiaturization , the effort to compress more circuit elements into smaller and smaller chip space is becoming the major trend in computer development. Besides, researchers are trying to develop more powerful and more advanced computers.Any customers all pass the operate system to use the calculator, not direct carry on the operation to the hardware of the calculators. The operate system is a bridge that communicates the customer and calculator. Every general-purpose computer must have an operating system to run other programs. Operating systems perform basic tasks and provide a software platform. The choice of operating systems determines to a great extent of the applications. Therefore OS is very important.The operate system is in the charge of Computer resource control program to execute system software. Say in a specific way，the OS is the most basic in the calculator software system, also constituting the part most importantly, it is responsible for the management and controls the calculator system in all hardware resources and the software resources, can make of various resources matched with mutually, moderating to work with one accord, full develop its function, exaltation the efficiency of the system, still take the interface function of the customer and the calculator system at the same time, use the calculator to provide the convenience for the customer. The operate system is a huge management control procedure, including 5 management functions mostly: Progress and processing the machine manage, the homework manage, saving management, equipments management, document management. Divide the line from the function, the tiny machine operate system can is divided into the single mission operate system, single many mission operate systems of customer and many mission operate systems of multi-user of single customer. At present there are several kinds of OS on the computer which are DOS, OS/2, UNIX, XENIX, LINUX, Window2000, Netware etc.In order for a computer to perform the required task, it must be given instructions in a language that it understands. However, the computer’s own binary based language, or machine language, is difficult for humans to use. Therefore, people devised an assembly language to shorten and simplify the process. In order to make a computer more friendly to use, programmers invented high level languages, such as COBOL, FORTRAN, ASSEMBLER, PASCAL, C++, etc, which made the computers easier to use. For the time being, HTML and XML are very useful languages as well.The database is often used to describe a collection of related data that is organized into an integrated, sophisticated structure that provides different people with varied access to the same data. A database management system is an extremely complex set of software programs that controls the organization, storage and retrieval of data in a database. A successful DBMS is often characterized with the four principal features: (1)Data Security and Integrity; (2)Interactive query; (3)Interactive data Entry and Updating; (4)Data Independence. The intelligent databases are becoming more popular in that they canprovide more validation. The researches on new types of database systems are underway.计算机倘若不是伴随着计算机的发展，现代世界的高端技术不可能出现。
计算机专业英语翻译参考
2.(P17)The most important piece of graphics hardware is the graphics card, which is the piece of equipment that renders out all images and sends them to a display. There are two types of graphics cards: integrated and dedicated. An integrated graphics card, usually by Intel for use in their computers, is bound to the motherboard and shares RAM (Random Access Memory) with the CPU, reducing the total amount of RAM available. This is undesirable for running programs and applications that use a large amount of video memory. A dedicated graphics card has its own RAM and Processor for generating its images, and does not slow down the computer. Dedicated graphics cards also have higher performance than integrated graphics cards. It is possible to have both dedicated and integrated graphicscard, however once a dedicated graphics card is installed, the integrated card will no longer function until the dedicated card is removed.
计算机科学与技术History-of-computing历史的计算学毕业论文英文文献翻译及原文
毕业设计（论文）外文文献翻译文献、资料中文题目：历史的计算文献、资料英文题目：History of computing文献、资料来源：文献、资料发表（出版）日期：院（部）：专业：计算机科学与技术班级：姓名：学号：指导教师：翻译日期： 2017.02.14毕业设计(论文)外文资料翻译系别计算机信息与技术系专业计算机科学与技术班级姓名学号外文出处附件 1. 原文； 2. 译文History of computingMain article: History of computing hardwareThe first use of the word "computer" was recorded in 1613, referring to a person who carried out calculations, or computations, and the word continued with the same meaning until the middle of the 20th century. From the end of the 19th century the word began to take on its more familiar meaning, a machine that carries outcomputations.Limited-function early computersThe Jacquard loom, on display at the Museum of Science and Industry in Manchester, England, was one of the first programmable devices.The history of the modern computer begins with two separate technologies, automated calculation and programmability, but no single device can be identified as the earliest computer, partly because of the inconsistent application of that term. A few devices are worth mentioning though, like some mechanical aids to computing, which were very successful and survived for centuries until the advent of the electronic calculator, like the Sumerian abacus, designed around 2500 BC of which a descendant won a speed competition against a modern desk calculating machine in Japan in 1946, the slide rules, invented in the 1620s, which were carried on five Apollo space missions, including to the moon and arguably the astrolabe and the Antikythera mechanism, an ancient astronomical computer built by the Greeks around 80 BC. The Greek mathematician Hero of Alexandria (c. 10–70 AD) built a mechanical theater which performed a play lasting 10 minutes and was operated by a complex system of ropes and drums that might be considered to be a means of deciding which parts of the mechanism performed which actions and when. This is the essence of programmability.Around the end of the 10th century, the French monk Gerbert d'Aurillac brought back from Spain the drawings of a machine invented by the Moors that answered either Yes or No to the questions it was asked. Again in the 13th century, the monks Albertus Magnus and Roger Bacon built talking androids without any further development.In 1642, the Renaissance saw the invention of the mechanical calculator, a device that could perform all four arithmetic operations without relying on human intelligence. The mechanical calculator was at the root of the development of computers in two separate ways. Initially, it was in trying to develop more powerful and more flexible calculators that the computer was first theorized by Charles Babbage and then developed. Secondly, development of a low-cost electronic calculator, successor to the mechanical calculator, resulted in the development by Intel of the first commercially available microprocessor integrated circuit.First general-purpose computersIn 1801, Joseph Marie Jacquard made an improvement to the textile loom by introducing a series of punched paper cards as a template which allowed his loom to weave intricate patterns automatically. The resulting Jacquard loom was an important step in the development of computers because the use of punched cards to define woven patterns can be viewed as an early, albeit limited, form of programmability.In 1837, Charles Babbage was the first to conceptualize and design a fully programmable mechanical computer, his analytical engine. Limited finances and Babbage's inability to resist tinkering with the design meant that the device was never completed ; nevertheless his son, Henry Babbage, completed a simplified version of the analytical engine's computing unit (the mill) in 1888. He gave a successful demonstration of its use in computing tables in 1906. This machine was given to the Science museum in South Kensington in 1910.In the late 1880s, Herman Hollerith invented the recording of data on a machine-readable medium. Earlier uses of machine-readable media had been for control, not data. "After some initial trials with paper tape, he settled on punched cards ..." To process these punched cards he invented the tabulator, and the keypunch machines. These three inventions were the foundation of the modern information processing industry. Large-scale automated data processing of punched cards was performed for the 1890 United States Census by Hollerith's company, which later became the core of IBM. By the end of the 19th century a number of ideas and technologies, that would later prove useful in the realization of practical computers, had begun to appear: Boolean algebra, the vacuum tube (thermionic valve), punched cards and tape, and the teleprinter.During the first half of the 20th century, many scientific computing needs were met by increasingly sophisticated analog computers, which used a direct mechanical or electrical model of the problem as a basis for computation. However, these were not programmable and generally lacked the versatility and accuracy of modern digital computers.Alan Turing is widely regarded as the father of modern computer science. In 1936 Turing provided an influential formalisation of the concept of the algorithm and computation with the Turing machine, providing a blueprint for the electronic digital computer. Of his role in the creation of the modern computer, Time magazine in naming Turing one of the 100 most influential people of the 20th century, states: "Thefact remains that everyone who taps at a keyboard, opening a spreadsheet or a word-processing program, is working on an incarnation of a Turing machine".EDSAC was one of the first computers to implement the stored-program (von Neumann) architecture.Die of an Intel 80486DX2 microprocessor (actual size: 12×6.75 mm) in its packaging.The Atanasoff–Berry Computer (ABC) was the world's first electronic digital computer, albeit not programmable. Atanasoff is considered to be one of the fathers of the computer.Conceived in 1937 by Iowa State College physics professor John Atanasoff, and built with the assistance of graduate student Clifford Berry, the machine was not programmable, being designed only to solve systems of linear equations. The computer did employ parallel computation. A 1973 court ruling in a patent dispute found that the patent for the 1946 ENIAC computer derived from the Atanasoff–Berry Computer.The first program-controlled computer was invented by Konrad Zuse, who built the Z3, an electromechanical computing machine, in 1941. The first programmable electronic computer was the Colossus, built in 1943 by Tommy Flowers.George Stibitz is internationally recognized as a father of the modern digital computer. While working at Bell Labs in November 1937, Stibitz invented and built a relay-based calculator he dubbed the "Model K" (for "kitchen table", on which he had assembled it), which was the first to use binary circuits to perform an arithmetic operation. Later models added greater sophistication including complex arithmetic and programmability.A succession of steadily more powerful and flexible computing devices were constructed in the 1930s and 1940s, gradually adding the key features that are seen in modern computers. The use of digital electronics (largely invented by Claude Shannon in 1937) and more flexible programmability were vitally important steps, but defining one point along this road as "the first digital electronic computer" is difficult. Notable achievements include. Konrad Zuse's electromechanical "Z machines". The Z3 (1941) was the first working machine featuring binary arithmetic, including floating point arithmetic and a measure of programmability. In 1998 the Z3 was proved to be Turing complete, therefore being the world's first operational computer.The non-programmable Atanasoff–Berry Computer (commenced in 1937, completed in 1941) which used vacuum tube based computation, binary numbers, andregenerative capacitor memory. The use of regenerative memory allowed it to be much more compact than its peers (being approximately the size of a large desk or workbench), since intermediate results could be stored and then fed back into the same set of computation elements.The secret British Colossus computers (1943), which had limited programmability but demonstrated that a device using thousands of tubes could be reasonably reliable and electronically reprogrammable. It was used for breaking German wartime codes.The Harvard Mark I (1944), a large-scale electromechanical computer with limited programmability.The U.S. Army's Ballistic Research Laboratory ENIAC (1946), which used decimal arithmetic and is sometimes called the first general purpose electronic computer (since Konrad Zuse's Z3 of 1941 used electromagnets instead of electronics). Initially, however, ENIAC had an inflexible architecture which essentially required rewiring to change its programming.Stored-program architectureReplica of the Small-Scale Experimental Machine (SSEM), the world's first stored-program computer, at the Museum of Science and Industry in Manchester, EnglandSeveral developers of ENIAC, recognizing its flaws, came up with a far more flexible and elegant design, which came to be known as the "stored-program architecture" or von Neumann architecture. This design was first formally described by John von Neumann in the paper First Draft of a Report on the EDV AC, distributed in 1945. A number of projects to develop computers based on the stored-program architecture commenced around this time, the first of which was completed in 1948 at the University of Manchester in England, the Manchester Small-Scale Experimental Machine (SSEM or "Baby"). The Electronic Delay Storage Automatic Calculator (EDSAC), completed a year after the SSEM at Cambridge University, was the first practical, non-experimental implementation of the stored-program design and was put to use immediately for research work at the university. Shortly thereafter, the machine originally described by von Neumann's paper—EDV AC—was completed but did not see full-time use for an additional two years.Nearly all modern computers implement some form of the stored-programarchitecture, making it the single trait by which the word "computer" is now defined. While the technologies used in computers have changed dramatically since the first electronic, general-purpose computers of the 1940s, most still use the von Neumann architecture.Beginning in the 1950s, Soviet scientists Sergei Sobolev and Nikolay Brusentsov conducted research on ternary computers, devices that operated on a base three numbering system of ?1, 0, and 1 rather than the conventional binary numbering system upon which most computers are based. They designed the Setun, a functional ternary computer, at Moscow State University. The device was put into limited production in the Soviet Union, but supplanted by the more common binary architecture.Semiconductors and microprocessorsComputers using vacuum tubes as their electronic elements were in use throughout the 1950s, but by the 1960s had been largely replaced by semiconductor transistor-based machines, which were smaller, faster, cheaper to produce, required less power, and were more reliable. The first transistorised computer was demonstrated at the University of Manchester in 1953. In the 1970s, integrated circuit technology and the subsequent creation of microprocessors, such as the Intel 4004, further decreased size and cost and further increased speed and reliability of computers. By the late 1970s, many products such as video recorders contained dedicated computers called microcontrollers, and they started to appear as a replacement to mechanical controls in domestic appliances such as washing machines. The 1980s witnessed home computers and the now ubiquitous personal computer. With the evolution of the Internet, personal computers are becoming as common as the television and the telephone in the household.Modern smartphones are fully programmable computers in their own right, and as of 2009 may well be the most common form of such computers in existenc.历史的计算主要文章:计算机硬件的历史在第一次使用“计算机”这个词被记录在1613年,指的是对一个人进行了计算,或计算,与词的意思相同,直到继续20世纪中期。
计算机专业中英文翻译(外文翻译、文献翻译)
英文参考文献及翻译Linux - Operating system of cybertimesThough for a lot of people , regard Linux as the main operating system to make up huge work station group, finish special effects of " Titanic " make , already can be regarded as and show talent fully. But for Linux, this only numerous news one of. Recently, the manufacturers concerned have announced that support the news of Linux to increase day by day, users' enthusiasm to Linux runs high unprecedentedly too. Then, Linux only have operating system not free more than on earth on 7 year this piece what glamour, get the favors of such numerous important software and hardware manufacturers as the masses of users and Orac le , Informix , HP , Sybase , Corel , Intel , Netscape , Dell ,etc. , OK?1.The background of Linux and characteristicLinux is a kind of " free (Free ) software ": What is called free,mean users can obtain the procedure and source code freely , and can use them freely , including revise or copy etc.. It is a result of cybertimes, numerous technical staff finish its research and development together through Inte rnet, countless user is it test and except fault , can add user expansion function that oneself make conveniently to participate in. As the most outstanding one in free software, Linux has characteristic of the following:(1)Totally follow POSLX standard, expand the network operatingsystem of supporting all AT&T and BSD Unix characteristic. Because of inheritting Unix outstanding design philosophy , and there are clean , stalwart , high-efficient and steady kernels, their all key codes are finished by Li nus Torvalds and other outstanding programmers, without any Unix code of AT&T or Berkeley, so Linu x is not Unix, but Linux and Unix are totally compatible.(2)Real many tasks, multi-user's system, the built-in networksupports, can be with such seamless links as NetWare , Windows NT , OS/2 , Unix ,etc.. Network in various kinds of Unix it tests to be fastest in comparing and assess efficiency. Support such many kinds of files systems as FAT16 , FAT32 , NTFS , Ex t2FS , ISO9600 ,etc. at the same time .(3) Can operate it in many kinds of hardwares platform , including such processors as Alpha , SunSparc , PowerPC , MIPS ,etc., to various kinds of new-type peripheral hardwares, can from distribute on global numerous programmer there getting support rapidly too.(4) To that the hardware requires lower, can obtain very good performance on more low-grade machine , what deserves particular mention is Linux outstanding stability , permitted " year " count often its running times.2.Main application of Linux At present,Now, the application of Linux mainly includes:(1) Internet/Intranet: This is one that Linux was used most at present, it can offer and include Web server , all such Inter net services as Ftp server , Gopher server , SMTP/POP3 mail server , Proxy/Cache server , DNS server ,etc.. Linux kernel supports IPalias , PPP and IPtunneling, these functions can be used for setting up fictitious host computer , fictitious service , VPN (fictitious special-purpose network ) ,etc.. Operating Apache Web server on Linux mainly, the occupation rate of market in 1998 is 49%, far exceeds the sum of such several big companies as Microsoft , Netscape ,etc..(2) Because Linux has outstanding networking ability , it can be usedin calculating distributedly large-scaly, for instance cartoon making , scientific caculation , database and file server ,etc..(3) As realization that is can under low platform fullness of Unix that operate , apply at all levels teaching and research work of universities and colleges extensively, if Mexico government announce middle and primary schools in the whole country dispose Linux and offer Internet service for student already.(4) Tabletop and handling official business appliedly. Application number of people of in this respect at present not so good as Windows of Microsoft far also, reason its lie in Lin ux quantity , desk-top of application software not so good as Windows application far not merely,because the characteristic of the freedom software makes it not almost have advertisement that support (though the function of Star Office is not second to MS Office at the same time, but there are actually few people knowing).3.Can Linux become a kind of major operating system?In the face of the pressure of coming from users that is strengthened day by day, more and more commercial companies transplant its application to Linux platform, comparatively important incident was as follows, in 1998 ①Compaq and HP determine to put forward user of requirement truss up Linux at their servers , IBM and Dell promise to offer customized Linux system to user too. ②Lotus announce, Notes the next edition include one special-purpose edition in Linux. ③Corel Company transplants its famous WordPerfect to on Linux, and free issue. Corel also plans to move the other figure pattern process products to Linux platform completely.④Main database producer: Sybase , Informix , Oracle , CA , IBM have already been transplanted one's own database products to on Linux, or has finished Beta edition, among them Oracle and Informix also offer technical support to their products.4.The gratifying one is, some farsighted domestic corporations have begun to try hard to change this kind of current situation already. Stone Co. not long ago is it invest a huge sum of money to claim , regard Linux as platform develop a Internet/Intranet solution, regard this as the core and launch Stone's system integration business , plan to set up nationwide Linux technical support organization at the same time , take the lead to promote the freedom software application and development in China. In addition domestic computer Company , person who win of China , devoted to Linux relevant software and hardware application of system popularize too. Is it to intensification that Linux know , will have more and more enterprises accede to the ranks that Linux will be used with domestic every enterprise to believe, more software will be planted in Linux platform. Meanwhile, the domestic university should regard Linux as the original version and upgrade already existing Unix content of courses , start with analysing the source code and revising the kernel and train a large number of senior Linux talents, improve our country's own operating system. Having only really grasped the operating system, the software industry of our country could be got rid of and aped sedulously at present, the passive state led by the nose byothers, create conditions for revitalizing the software industry of our country fundamentally.中文翻译Linux—网络时代的操作系统虽然对许多人来说，以Linux作为主要的操作系统组成庞大的工作站群，完成了《泰坦尼克号》的特技制作，已经算是出尽了风头。
论文中英文翻译(译文)
编号：桂林电子科技大学信息科技学院毕业设计(论文)外文翻译（译文）系别：电子工程系专业：电子信息工程学生姓名：韦骏学号：0852100329指导教师单位：桂林电子科技大学信息科技学院姓名：梁勇职称：讲师2012 年6 月5 日设计与实现基于Modbus 协议的嵌入式Linux 系统摘要：随着嵌入式计算机技术的飞速发展，新一代工业自动化数据采集和监测系统，采用核心的高性能嵌入式微处理器的，该系统很好地适应应用程序。
它符合消费等的严格要求的功能，如可靠性，成本，尺寸和功耗等。
在工业自动化应用系统，Modbus 通信协议的工业标准，广泛应用于大规模的工业设备系统，包括DCS，可编程控制器，RTU 及智能仪表等。
为了达到嵌入式数据监测的工业自动化应用软件的需求，本文设计了嵌入式数据采集监测平台下基于Modbus 协议的Linux 环境采集系统。
串行端口的Modbus 协议是实现主/从式，其中包括两种通信模式：ASCII 和RTU。
因此，各种药膏协议的设备能够满足串行的Modbus通信。
在Modbus 协议的嵌入式平台实现稳定和可靠。
它在嵌入式数据监测自动化应用系统的新收购的前景良好。
关键词：嵌入式系统，嵌入式Linux，Modbus 协议，数据采集，监测和控制。
1、绪论Modbus 是一种通讯协议，是一种由莫迪康公司推广。
它广泛应用于工业自动化，已成为实际的工业标准。
该控制装置或不同厂家的测量仪器可以链接到一个行业监控网络使用Modbus 协议。
Modbus 通信协议可以作为大量的工业设备的通讯标准，包括PLC，DCS 系统，RTU 的，聪明的智能仪表。
随着嵌入式计算机技术的飞速发展，嵌入式数据采集监测系统，使用了高性能的嵌入式微处理器为核心，是一个重要的发展方向。
在环境鉴于嵌入式Linux 的嵌入式工业自动化应用的数据，一个Modbus 主协议下的采集监测系统的设计和实现了这个文件。
因此，通信设备，各种药膏协议能够满足串行的Modbus。
计算机专业B-S模式 中英文 文献
外文翻译ENGLISHE：Develop Web application program using ASP the architecture that must first establish Web application. Now in application frequently with to have two: The architecture of C/S and the architecture of B/S.Client/server and customer end / server hold the architecture of C/S.The customer / server structure of two floor.Customer / server ( Client/Server ) model is a kind of good software architecture, it is the one of best application pattern of network. From technology, see that it is a logic concept, denote will a application many tasks of decomposing difference carry out , common completion is entire to apply the function of task. On each network main computer of web site, resource ( hardware, software and data ) divide into step, is not balanced, under customer / server structure, without the client computer of resource through sending request to the server that has resource , get resource request, so meet the resource distribution in network not balancedness. With this kind of structure, can synthesize various computers to cooperate with work, let it each can, realize the scale for the system of computer optimization ( Rightsizing ) with scale reduce to melt ( Downsizing ). Picture is as follows:It is most of to divide into computer network application into two, in which the resource and function that part supports many users to share , it is realized by server; Another part faces every user , is realized by client computer, also namely, client computer is usual to carry out proscenium function , realizes man-machine interaction through user interface , or is the application program of specific conducted user. And server usually carries out the function of backstage supporter , manages the outside request concerning seting up, accepting and replying user that shared. For a computer, it can have double function , is being certain and momentary to carve to act as server , and again becomes client computer in another time.Customer / server type computer divide into two kinds, one side who offers service is called as server , asks one side of service to be called as customer. To be able to offer service, server one side must have certain hardware and corresponding server software; Also, customer one side mustalso have certain hardware and corresponding customer software.There must be a agreement between server and customer, both sides communicate according to this agreement.Apply customer / server model in Internet service , the relation between customer and server is not immutable. Some Internet node offers service on the one hand , also gets service on the other hand from other node; It is even in one time dialogue course, mutual role also exchanges probably. As in carry out file transmission , if be called as one side who offers file server, is called as one side who gets file customer, when using get or mget order since another node takes file, can think that what self use and it is client computer , is using put or mput order to another node dispatch file can again think the machine that used self is server.Multilayer customer / server structureAlong with the development of enterprise application, recently, have again arisen a kind of new multilayer architecture, it applies customer end to divide into two minutes: Customer application and server apply. Customer application is the part of original customer application , is another and partial to have been transfered to server to apply. New customer application takes the responsibility for user interface and simple regular business logic and new server application resident core , changeable business logic. Therefore its structure has become new ( Client application + Server application )/Server structure. Following picture shows:This kind of structure has solved traditional Client/Server can expand problem, have reduced customer end business logic , and have reduced the requirement of customer end for hardware. At the same time because of a lot of business logic concentrations have gone to unitary application server on, the maintenance work of application system had been also concentrated together, have eliminated the problem in the traditional structure of Client/Server that software distributes. This kind of structure is called as the architecture of B/S.Browser/Server and browser / server hold the architecture of B/S. Onessence, Browser/Server is also a kind of structure of Client/Server, it is a kind of from the traditional two levels of structural development of Client/Server come to the three-layer structural special case of Client/Server that applied on Web.In the system of Browser/Server, user can pass through browser to a lot of servers that spread on network to send request. The structure of Browser/Server is maximum to have simplified the work of client computer, on client computer, need to install and deploy few customer end software only , server will bear more work, for database visit and apply program carry out will in server finish.Under the three-layer architecture of Browser/Server, express layer ( Presentatioon ) , function layer ( Business Logic ) , data layer ( Data Service ) have been cut the unit of 3 relative independences: It is the first layer of to express layer: Web browser.In expressing layer contain system show logic, locate in customer end. It's task is to suggest by Web browser to the certain a Web server on network that service is asked , after verifying for user identity, Web server delivers needed homepage with HTTP agreement to customer end, client computer accept the homepage file that passed , and show it in Web browser on.Second layer function layer: Have the Web server of the application function of program extension.In function layer contain the systematic handling of general affairs logic, locate in Web server end. It's task is the request concerning accepting user , need to be first conducted and corresponding to expand application program and database to carry out connection , passes through the waies such as SQL to database server to put forward data handling to apply for, then etc. database server the result of handling data submit to Web server, deliver again by Web server to return customer end.The number of plies of 3th according to layer: Database server.In data layer contain systematic data handling logic, locate in database server end. It's task is to accept the request that Web server controls for database, realization is inquired and modified for database , update etc. function, submit operation result to Web server.Careful analysis is been easy to see , the architecture of Browser/Server of three-layer is the handling of general affairs of the two levels of structure of Client/Server logic modular from the task of client computer in split , from the first floor of individual composition bear the pressure of its task and such client computer have alleviated greatly, distribute load balancedly and have given Web server, so from the structural change of Client/server of original two floor the structure of Browser/Server of three-layer. This kind of three-layer architecture following picture shows.This kind of structure not only client computer from heavy burden andthe requirement of performance that rises continuously for it in liberation come out , also defend technology people from heavy maintenance upgrading work in free oneself. Since client computer handles general affairs , logic partial minutes have given function server, make client computer right off " slender " a lot of, do not take the responsibility for handling complex calculation and data again visit etc. crucial general affairs, is responsible to show part, so, maintenance people do not rush about again for the maintenance work of program between every client computer, and put major energy in the program on function server update work. Between this kind of three-layer structural layer and layer, the mutually independent change of any first floor does not affect the function of other layer. It has changed the defect of the two levels of architecture of Client/Server of tradition from foundation, it is the transform with deep once in application systematic architecture.The contrast of two architecturesThe architecture of Browser/Server and the architecture ofClient/Server compare with all advantages that not only have the architecture of Client/Server and also have the architecture ofClinet/Server the unique advantage that place does not have: Open standard: The standard adopted by Client/Server only in department unification for but, it's application is often for special purpose.It is lower to develop and defend cost: It need to be implemented on all client computers that the application of Client/Server must develop the customer end software for special purpose, no matter installation and disposition escalate still, have wasted manpower and material resources maximumly. The application of Browser/Server need in customer end have general browser , defend and escalate to work in server end go on , need not carry out any change as customer holds , have reduced the cost of development and maintenance so greatly.It is simple to use , interface friendly: The interface of the user of Client/Server is decided by customer end software, interface and the method of its use are not identical each, per popularize a system of Client/Server ask user study from the beginning, is hard to use. The interface of the user of Browser/Server is unified on browser, browser is easy to use , interface friendly, must not study use again other software, the use of a Lao Yong Yi that has solved user problem.Customer end detumescence: The customer end of Client/Server has the function that shows and handles data , as the requirement of customer end is a client computer " it is fat " very high. The customer of Browser/Server holds the access that not takes the responsibility for database again and the etc. task of complex data calculation, need it only show , the powerful role that has played server fully is so large to have reduced the requirement for customer end, customer end become very " thin ".System is flexible: The 3 minutes of the system of Client/Server, in modular, have the part that need to change to want relation to the change of other modular, make system very difficult upgrading. The 3 minutes of the system of Browser/Server modular relative independence, in which a part of modular change, other modular does not get influence, it is very easy that system improve to become, and can form the system with much better performance with the product of different manufacturer.Ensure systematic safety: In the system of Client/Server, directly join with database server because of client computer, user can very easily change the data on server, can not guarantee systematic safety. The system of Browser/Server has increased a level of Web server between client computer and database server , makes two not to be directly linked again, client computer can not be directly controled for database, prevent user efficiently invade illegally.The architecture of Browser/Server of three-layer has the advantage that a lot of traditional architectures of Client/Server does not have , and is close to have combined the technology of Internet/Intranet, is that the tendency of technical development tends to , it application system tape into one brand-new develop times. From this us option the configuration of B/S the architecture that develops as system.what are C/S with B/SFor " C/S " with the technology of " B/S " develop change know , first,must make it clear that 3 problems.( 1 ) What is the structure of C/S.C/S ( Client/Server ) structure, the server structure and client computer that all know well. It is software systematic architecture, through it can hold hardware environment fully using two advantage, realize task reasonable distribution to Client end and Server end , have reduced systematic communication expense. Now, the most systems of application software are the two levels of structure of the form of Client/Server , are developing to the Web application of distribution type since current software application is systematic, Web and the application of Client/Server can carry out same business handling , apply different modular to share logic assembly; Therefore it is systematic that built-in and external user can visit new and existing application , through the logic in existing application system, can expand new application system. This is also present application system develop direction. Traditional C ／S architecture though adopting is open pattern, but this is the openness that system develops a level , in specific application no matter Client end orServer end the software that need to still specify support. Because of the software software that need to develop different edition according to the different system of operating system that can not offer the structure of C/S and the open environment of user genuine expectation , besides, the renovation of product is very rapid, is nearly impossible to already meet the 100 computer above users of local area network at the same time use. Price has low efficiency high. If my courtyard uses , Shanghai exceed the orchid company's management software " statistics of law case" is typical C ／S architecture management software.( 2 ) What is the structure of B/S.B/S ( Browser/Server ) structure browser and server structure. It is along with the technology of Internet spring up , it is for the structure of improvement or a kind of change of the structure of C/S. Under this kind of structure, user working interface is to realize through WWW browser, lose the logic of general affairs very much in front( Browser) realization, but the major logic of general affairs in server end( Server) realization, form the three-layer claimed 3-tier structure. So, have simplified customer end computer load greatly , have alleviated system to defend workload and the cost with upgrading , have reduced the overall cost of user ( TCO ). With present technology see , local area network the network application that establishes the structure of B/S , and under the pattern of Internet/Intranet, database application is easy to hold relatively , cost also is lower. It is that oneness goes to the development of position , can realize different people, never same place, with difference receive the way of entering ( for example LAN, WAN, Internet/Intranet etc.) visit and operate common database; It can protect data platform efficiently with management visit limits of authority, server database is also safe. Now in my courtyard, net ( Intranet ) , outer net ( Internet ) with Beijing eastern clear big company " law case and the management software of official business " is the structural management software of B/S , policemen each working station in local area network pass through WWW browser can realize working business. Especially in JAVA step platform language appearance after, the configuration management software of B/S is more facilitated , is shortcut, efficient.( 3 ) The management software technology of main stream.The technology of main stream of management software technology is as management thought , have also gone through 3 develop period. First, interface technology goes to Windows graph interface ( or graph user interface GUI ) from last century DOS character interface, till Browser browser interface 3 differences develop period. Secondly, today own the browser interface of computer, is not only visual and is easy to use , what is more major is that any its style of application software based on browser platform is as, make the requirement of choosing a person for the job for operating training not high and software operability is strong , is easy to distinguish; Moreover platform architecture the file that also goes to today from past single user development ／server ( F ／S ) system and client computer ／server ( C ／S ) system and browser ／server ( B ／S ) system.The comparison of C/S and B/SC/S and B/S is the now world two technologies of main stream of developing pattern technical configuration. C/S is that American Borland company researches and develop most early, B/S is that American Microsoft researches and develop. Now this two technologies with quilt world countries grasp , it is many that domestic company produce article with C/S and the technical development of B/S. This two technologies have the certain market share of self , is with customer crowd , each domestic enterprise says that own management software configuration technical function is powerful, advanced, convenient , the customer group that can lift , have a crowd scholar ink guest to shake flag self cry out , advertisement flies all over the sky , may be called benevolent to see kernel, sage sees wisdomC/S configures inferior position and the advantage of software( 1 ) Application server operation data load is lightcomparatively.The database application of the most simple architecture of C/S is become by two partial groups, customer applies program and database server program. Both can be called as proscenium program and the program of backstage supporter respectively. The machine of operation database server program is also called as application server. Once server program had been started , waits the request concerning responding customer program hair at any time; Customer application program operation can becalled as customer computer on the own computer of user, in correspondence with database server, when needs carry out any operation for the data in database, customer program seeks server program voluntarily , and sends request to it, server program is regular as basis intends to make to reply, send to return result, application server operation data load is lighter.( 2 ) Data store management function relatively transparent.In database application data store management function, is carried out respectively independently by server program and customer application program , is regular as proscenium application can violate , and usually those different( no matter is have known still unknown ) operations data, in server program, do not concentrate realization, for instance visit limits of authority, serial number can be repeated , must have customer talent establishment the rule order. It is these to own , for the last user that works on proscenium program is " transparent ", they need not be interest in ( can not usually also interfere ) the course of behind, can complete own all work. In the application of customer server configuration proscenium program not is very " thin ", troublesome matter is delivered to server and network. In the system of C/S take off , database can not become public really , professionally more competent storehouse, it gets independent special management.( 3 ) The inferior position of the configuration of C/S is high maintenance cost make investment just big.First, with the configuration of C/S, will select proper database platform to realize the genuine "unification" of database data, make the data synchronism that spreads in two lands complete deliver by database system go to manage, but the logically two operators of land will directly visit a same database to realize efficiently , have so some problems, if needs establishment the data synchronism of " real time ", the database server that must establish real time communication connection between two places and maintains two lands is online to run , network management staff will again want to defend and manage for customer end as server defends management , maintenance and complex tech support and the investment of this high needs have very high cost, maintenance task is measured.Secondly, the software of the structure of C/S of tradition need to develop thesoftware of different edition according to the different system of operating system , is very rapid because of the renovation of product, price is working needs high with inefficient already do not meet. In JAVA step platform language appearance after, the configuration of B/S is more vigorous impact C/S , and forms threat and challenge for it. .The advantage of B/S configuration software( 1 ) The Maintenance of inferior position and upgrading way are simple.Now upgrading and the improvement of software system more and more frequently, the product of the configuration of B/S embodies more convenient property obviously. For one a little a little bit big unit , if systematic administrator needs , between hundreds of 1000 even last computers round trip run , efficiency and workload is to can imagine, but the configuration of B/S software needs management server have been all right , all customer ends are browser only, need not do any maintenance at all. No matter the scale of user has , is what , has how many branch will not increase any workload of maintenance upgrading , is all to operate needs to aim at server to go on; If need differently only, net server connection specially , realize long-range maintenance and upgrading and share. So client computer more and more " thin ", and server more and more " fat " is the direction of main stream of future informative development. In the future, software upgrading and maintenance will be more and more easy , and use can more and more simple, this is for user manpower , material resources, time and cost save is obvious , it is astonishing. Therefore defend and escalate revolutionary way is the client computer " it is thin ", " is fat " server.( 2 ) Cost reduction, it is more to select.All know windows in the computer of top of a table on nearly one Tong world, browser has become standard disposition, but on server operating system, windows is in absolute dominance position not. Current tendency is the application management software that uses the configuration of B/S all , need to install only in Linux server on , and safety is high. The so server option of operating system is many, no matter choosing those operating system, can let the most of ones use windows in order to the computer of top of a table of operating system does not get influence, this for make most popular free Linux operating system develop fast, Linux except operatingsystem is free besides, it is also free to link database, this kind of option is very pupular.Say, many persons on daily, "Sina website" nets , so long as having installed browser for can , and what need not know the server of " Sina website " to use is that what operating system, and in fact the most of websites do not use windows operating system really, but the computer of user is most of as installing to be windows operating system.( 3 ) Application server operation data load value comparatively.Since B/S configures management, software installation in server end ( Server ) on, it is been all right that network administrator need to manage server only, the user interface major logic of general affairs in server ( Server ) end pass through WWW browser completely realization, lose the logic of general affairs very much in front( Browser) realization, all customer ends has only browser, network administrator need to do hardware maintenance only. But application server operation data load is heavier, once occuring " server collapse " to wait for problem, consequence is unimaginable. Therefore a lot of units have database to stock server , are ready for any eventuality.原文翻译:利用ASP开发Web应用程序首先必须确立Web应用的体系结构。
论文外文文献翻译
论文外文文献翻译以下是一篇700字左右的论文外文文献翻译：原文题目：The Role of Artificial Intelligence in Medical Diagnostics: A Review原文摘要：In recent years, there has been a growing interest in the use of artificial intelligence (AI) in the field of medical diagnostics. AI has the potential to improve the accuracy and efficiency of medical diagnoses, and can assist clinicians in making treatment decisions. This review aims to examine the current state of AI in medical diagnostics, and discuss its advantages and limitations. Several AI techniques, including machine learning, deep learning, and natural language processing, are discussed. The review also examines the ethical and legal considerations associated with the use of AI in medical diagnostics. Overall, AI has shown great promise in improving medical diagnostics, but further research is needed to fully understand its potential benefits and limitations.AI在医学诊断中发挥的作用：一项综述近年来，人工智能（AI）在医学诊断领域的应用引起了越来越多的关注。
计算机科学与技术毕业设计(论文)外文翻译
本科毕业设计(论文) 外文翻译（附外文原文）系 ( 院 )：信息科学与工程学院课题名称：学生信息管理系统专业(方向)：计算机科学与技术（应用）7.1 Enter ActionMappingsThe Model 2 architecture (see chapter 1) encourages us to use servlets and Java- Server Pages in the same application. Under Model 2, we start by calling a servlet.The servlet handles the business logic and directs control to the appropriate pageto complete the response.The web application deployment descriptor (web.xml) lets us map a URL patternto a servlet. This can be a general pattern, like *.do, or a specific path, like saveRecord.do.Some applications implement Model 2 by mapping a servlet to each business operation. This approach works, but many applications involve dozens or hundredsof business operations. Since servlets are multithreaded, instantiating so manyservlets is not the best use of server resources. Servlets are designed to handle anynumber of parallel requests. There is no performance benefit in simply creatingmore and more servlets.The servlet’s primary job is to interact with the container and HTTP. Handlinga business operation is something that a servlet could delegate to another component. Struts does this by having the ActionServlet delegate the business operationto an object. Using a servlet to receive a request and route it to a handler is knownas the Front Controller pattern [Go3].Of course, simply delegating the business operation to another componentdoes not solve the problem of mapping URIs [W3C, URI] to business operations.Our only way of communicating with a web browser is through HTTP requests and URIs. Arranging for a URI to trigger a business operation is an essential part of developing a web application.Meanwhile, in practice many business operations are handled in similar ways.Since Java is multithreaded, we could get better use of our server resources if wecould use the same Action object to handle similar operations. But for this towork, we might need to pass the object a set of configuration parameters to usewith each operation.So what’s the bottom line? To implement Model 2 in an efficient and flexibleway, we need to:Enter ActionMappings 195♉ Route requests for our business operations to a single servlet♉ Determine which business operation is related to the request♉ Load a multithreaded helper object to handle the business operation♉ Pass the helper object the specifics of each request along with any configuration detail used by this operationThis is where ActionMappings come in.7.1.1 The ActionMapping beanAn ActionMapping (org.apache.struts.action.ActionMapping) describes howthe framework handles each discrete business operation (or action). In Struts,each ActionMapping is associated with a specific URI through its path property. When a request comes in, the ActionServlet uses the path property to select the corresponding ActionMapping. The set of ActionMapping objects is kept in an ActionMappings collection (org.apache.struts.action.ActionMappings). Originally, the ActionMapping object was used to extend the Action objectrather than the Action class. When used with an Action, a mapping gives a specific Action object additional responsibilities and new functionality. So, it was essentiallyan Action decorator [Go4]. Along the way, the ActionMapping evolved into anobject in its own right and can be used with or without an Action.DEFINITION The intent of the decorator pattern is to attach additional responsibilities to an object dynamically. Decorators provide a flexible alternative to subclassingfor extending functionality [Go4].The ActionMappings are usually created through the Struts configuration file.For more about this file, see chapter 4.7.1.2 The ActionMappings catalogThe ActionMappings catalog the business logic available to a Struts application.When a request comes in, the servlet finds its entry in the ActionMappings catalogand pulls the corresponding bean.The ActionServlet uses the ActionMapping bean to decide what to do next. Itmay need to forward control off to another resource. Or it may need to populateand validate an ActionForm bean. At some point, it may have to pass control to an Action object, and when the Action returns, it may have to look up an Action-Forward associated with this mapping.196 CHAPTER 7Designing with ActionMappingsThe ActionMapping works like a routing slip for the servlet. Depending onhow the mapping is filled out, the request could go just about anywhere.The ActionMappings represent the core design of a Struts application. If youwant to figure out how a Struts application works, start with the ActionMappings. Ifyou want to figure out how to write a new Struts application, start with the Action- Mappings. The mappings are at the absolute center of every Struts application.In this chapter, we take a close look at the ActionMapping properties andexplore how they help you design the flow of a Struts application.1.0 vs 1.1 In Struts 1.1, ActionMapping subclasses ActionConfig (org.apache. struts.config.ActionConfig) and adds API methods required forbackward compatibility. ActionMapping is not deprecated, and how thehierarchy will be handled in future releases has not been determined.For now, we refer to the ActionMapping class, but you should note thatin Struts 1.1 all of the action properties are actually defined by the ActionConfigsuper class. The ActionMapping class otherwise works thesame way in both versions.7.2 ActionMapping propertiesTable 7.1 describes the base ActionMapping properties. As with other configuration components, developers may extend ActionMapping to provide additionalproperties.Table 7.1 The base ActionMapping propertiesProperty Descriptionpath The URI path from the request used to select this mapping. (API command) forward The context-relative path of the resource that should serve this request via a forward.Exactly one of the forward, include, or type properties must be specified.orinclude The context-relative path of the resource that should serve this request via aninclude. Exactly one of the forward, include, or type properties must be specified.ortype Optionally specifies a subclass oforg.apache.struts.action.ActionMappingthat should be used when instantiating this mapping.className The fully qualified name of the Action class used by this mapping. SinceStruts 1.1ActionMapping properties 197In the sections that follow, we take a look at each of these properties.7.2.1 The path propertyThe ActionMapping URI, or path, will look to the user like just another file onthe web server. But it does not represent a file. It is a virtual reference to our ActionMapping.Because it is exposed to other systems, the path is not really a logical name, likethose we use with ActionForward. The path can include slashes and an extension—as if it referred to a file system—but they are all just part of a single name.The ActionMappings themselves are a “flat” namespace with no type of internalhierarchy whatsoever. They just happen to use the same characters that we areused to seeing in hierarchical file systems.name The name of the form bean, if any, associated with this action. This is not the classname. It is the logical name used in the form bean configuration.roles The list of security roles that may access this mapping.scope The identifier of the scope (request or session) within which the form bean, if any,associated with this mapping will be created.validate Set to true if the validate method of the form bean (if any) associated with thismapping should be called.input Context-relative path of the input form to which control should be returned ifa validationerror is encountered. This can be any URI: HTML, JSP, VM, or another Action- Mapping.parameter General-purpose configuration parameter that can be used to pass extra informationto the Action selected by this ActionMapping.attribute Name of the request-scope or session-scope attribute under which our form bean isaccessed, if it is other than the bean's specified name.prefix Prefix used to match request parameter names to form bean property names, if any.suffix Suffix used to match request parameter names when populating the properties ofour ActionForm bean, if any.unknown Can be set to true if this mapping should be configured as the default for this application(to handle all requests not handled by another mapping). Only one mappingcan be defined as the default unknown mapping within an application.forwards(s) Block of ActionForwards for this mapping to use, if any.exception(s) Block of ExceptionHandlers for this mapping to use, if any.Table 7.1 The base ActionMapping properties (continued)Property DescriptionSinceStruts 1.1SinceStruts 1.1198 CHAPTER 7Designing with ActionMappingsOf course, it can still be useful to treat your ActionMappings as if they werepart of a hierarchy and group related commands under the same "folder." Theonly restriction is that the names must match whatever pattern is used in the application’s deployment description (web.xml) for the ActionServlet. This is usuallyeither /do/* or *.do, but any similar pattern can be used.If you are working in a team environment, different team members can begiven different ActionMapping namespaces to use. Some people may be workingwith the /customer ActionMappings, others may be working with the /vendor ActionMappings. This may also relate to the Java package hierarchy the team isusing. Since the ActionMapping URIs are logical constructs, they can be organizedin any way that suits your project.With Struts 1.1, these types of namespaces can be promoted to applicationmodules. Each team can work independently on its own module, with its own setof configuration files and presentation pages. Configuring your application to use multiple modules is covered in chapter 4.DEFINITION The web runs on URIs, and most URIs map to physical files. If you want to change the resource, you change the corresponding file. Some URIs, likeStruts actions, are virtual references. They do not have a correspondingfile but are handled by a programming component. To change the resource,we change how the component is programmed. But since thepath is a URI and interacts with other systems outside our control, thepath is not a true logical reference—the name of an ActionForward, forinstance. We can change the name of an ActionForward without consultingother systems. It’s an internal, logical reference. If we change thepath to an ActionMapping, we might need to update other systems thatrefer to the ActionMapping through its public URI.7.2.2 The forward propertyWhen the forward property is specified, the servlet will not pass the request to an Action class but will make a call to RequestDispatcher.forward. Since the operationdoes not use an Action class, it can be used to integrate Struts with otherresources and to prototype systems. The forward, include, and type propertiesare mutually exclusive. (See chapter 6 for more information.)7.2.3 The include propertyWhen the include property is specified, the servlet will not pass the request to an Action class but will make a call to RequestDispatcher.include. The operationActionMapping properties 199does not use an Action class and can be used to integrate Struts with other components. The forward, include, and type properties are mutually exclusive. (Seechapter 6 for more information.)7.2.4 The type propertyMost mappings will specify an Action class type rather than a forward or include.An Action class may be used by more than one mapping. The mappings may specifyform beans, parameters, forwards, or exceptions. The forward, include, andtype properties are mutually exclusive.7.2.5 The className propertyWhen specified, className is the fully qualified Java classname of the ActionMapping subclass that should be used for this object. This allows you to use your own ActionMapping subclass with specialized methods and properties. See alsosection 7.4.7.2.6 The name propertyThis property specifies the logical name for the form bean, as given in the formbean segment of the Struts configuration file. By default, this is also the name tobe used when placing the form bean in the request or session context. Use theattribute property of this class to specify a different attribute key.7.2.7 The roles propertyThis property is a comma-delimited list of the security role names that are allowed access to this ActionMapping object. By default, the same system that is used with standard container-based security is applied to the list of roles given here. Thismeans you can use action-based security in lieu of specifying URL patterns in the deployment descriptor, or you can use both together.The security check is handled by the processRoles method of the Request- Processor (org.apache.struts.action.RequestProcessor). By subclassing RequestProcessor, you can also use the roles property with application-based security. See chapter 9 for more about subclassing RequestProcessor.7.2.8 The scope propertyThe ActionForm bean can be stored in the current request or in the session scope (where it will be available to additional requests). While most developers userequest scope for the ActionForm, the framework default is session scope. Tomake request the default, see section 7.4.SinceStruts 1.1SinceStruts 1.1200 CHAPTER 7Designing with ActionMappings7.2.9 The validate propertyAn important step in the lifecycle of an ActionForm is to validate its data before offering it to the business layer. When the validate property for a mapping is true, the ActionServlet will call the ActionForm’s validate method. If validate returns false, the request is forwarded to the resource given by the input property.Often, developers will create a pair of mappings for each data entry form. Onemapping will have validate set to false, so you can create an empty form. Theother has validate set to true and is used to submit the completed form.NOTE Whether or not the ActionForm validate method is called does not relateto the ActionServlet’s validating property. That switch controlshow the Struts configuration file is processed.7.2.10 The input propertyWhen validate is set to true, it is important that a valid path for input be provided. This is where control will pass should the ActionForm validate methodreturn false. Often, this is the address for a presentation page. Sometimes it willbe another Action path (with validate set to false) that is required to generatedata objects needed by the page.NOTE The input path often leads back to the page that submitted the request.While it seems natural for the framework to return the request to whereit originated, this is not a simple task in a web application. A request is oftenpassed from component to component before a response is sent backto the browser. The browser only knows the path it used to retrieve theinput page, which may or may not also be the correct path to use for theinput property. While it may be possible to try and generate a default inputpage based on the HTTP referrer attribute, the Struts designersdeemed that approach unreliable.inputForwardIn Struts 1.0, the ActionMapping input property is always a literal URI. InStruts 1.1, it may optionally be the name of an ActionForward instead. The ActionForward is retrieved and its path property is used as the input property.This can be a global or local ActionForward.To use ActionForwards here instead of literal paths, set the inputForwardattribute on the <controller> element for this module to true:SinceStruts 1.1ActionMapping properties 201<controller inputForward="true">For more about configuring Struts, see chapter 4. For more about ActionForwards,see chapter 6.7.2.11 The parameter propertyThe generic parameter property allows Actions to be configured at runtime. Severalof the standard Struts Actions make use of this property, and the standardScaffold Actions often use it, too. The parameter property may contain a URI, the name of a method, the name of a class, or any other bit of information an Actionmay need at runtime. This flexibility allows some Actions to do double and tripleduty, slashing the number of distinct Action classes an application needs on hand.Within an Action class, the parameter property is retrieved from the mappingpassed to perform:parameter = mapping.getParameter();Multiple parametersWhile multiple parameters are not supported by the standard ActionMappingsclass, there are some easy ways to implement this, including using HttpUtils, a StringTokenizer, or a Properties file (java.util.Properties).HttpUtils. Although deprecated as of the Servlet API 2.3 specification, theHttpUtils package (javax.servlet.http.HttpUtils) provides a static method that parses any string as if it were a query string and returns a Hashtable(java.util.Hashtable):Hashtable parameters = parseQueryString(parameter);The parameter property for your mapping then becomes just another query string, because you might use it elsewhere in the Struts configuration. stringTokenizer. Another simple approach is to delimit the parameters using the token of your choice—such as a comma, colon, or semicolon—and use the StringTokenizer to read them back:StringTokenizer incoming =new StringTokenizer(mapping.getParameter(),";");int i = 0;String[] parameters = new String[incoming.countTokens()]; while (incoming.hasMoreTokens()) {parameters[i++] = incoming.nextToken().trim();}202 CHAPTER 7Designing with ActionMappingsProperties file. While slightly more complicated than the others, another popular approach to providing multiple parameters to an ActionMapping is with a standard Properties files (java.util.Properties). Depending on your needs, the Properties file could be stored in an absolute location in your file system or anywhere on your application’s CLASSPATH.The Commons Scaffold package [ASF, Commons] provides a ResourceUtils package (mons.scaffold.util.ResourceUtils) with methods forloading a Properties file from an absolute location or from your application’s CLASSPATH.7.2.12 The attribute propertyFrom time to time, you may need to store two copies of the same ActionForm inthe same context at the same time. This most often happens when ActionFormsare being stored in the session context as part of a workflow. To keep their names from conflicting, you can use the attribute property to give one ActionForm bean a different name.An alternative approach is to define another ActionForm bean in the configuration, using the same type but under a different name.7.2.13 The prefix and suffix propertiesLike attribute, the prefix and suffix properties can be used to help avoid naming conflicts in your application. When specified, these switches enable aprefix or suffix for the property name, forming an alias when it is populatedfrom the request.If the prefix this was specified, thenthisName=McClanahanbecomes equivalent toname=McClanahanfor the purpose of populating the ActionForm. Either or both parameters would call getName("McClanahan");This does not affect how the properties are written by the tag extensions. It affects how the autopopulation mechanism perceives them in the request.Nested components 2037.2.14 The unknown ActionMappingWhile surfing the Web, most of us have encountered the dreaded 404— page not found message. Most web servers provide some special features for processing requests for unknown pages, so webmasters can steer users in the right direction. Struts offers a similar service for ActionMapping 404s—the unknown ActionMapping. In the Struts configuration file, you can specify one ActionMapping toreceive any requests for an ActionMapping that would not otherwise be matched:<actionname="/debug"forward="/pages/debug.jsp"/>When this option is not set, a request for an ActionMapping that cannot bematched throws400 Invalid path /notHere was requestedNote that by a request for an ActionMapping, we mean a URI that matches the prefix or suffix specified for the servlet (usually /do/* or *.do). Requests for other URI patterns, good or bad, will be handled by other servlets or by the container:/do/notHere (goes to the unknown ActionMapping)/notHere.txt (goes to the container)7.3 Nested componentsThe ActionMapping properties are helpful when it comes to getting an Action torun a business operation. But they tell only part of the story. There is still much todo when the Action returns.An Action may have more than one outcome. We may need to register several ActionForwards so that the Action can take its pick.7.3.1 Local forwardsIn the normal course, an ActionMapping is used to select an Action object to handle the request. The Action returns an ActionForward that indicates which pageshould complete the response.The reason we use ActionForwards is that, in practice, presentation pages areeither often reused or often changed, or both. In either case, it is good practice to encapsulate the page’s location behind a logical name, like “success” or “failure.”The ActionForward object lets us assign a logical name to any given URI.204 CHAPTER 7Designing with ActionMappingsOf course, logical concepts like success or failure are often relative. What represents success to one Action may represent failure to another. Each Action-Mapping can have its own set of local ActionForwards. When the Action asks for a forward (by name), the local set is checked before trying the global forwards. See chapter 6 for more about ActionForwards.Local forwards are usually specified in the Struts configuration file. See chapter4 for details.7.3.2 Local exceptionsMost often, an application’s exception handlers (org.apache.struts.action. ExceptionHandler) can be declared globally. However, if a given ActionMapping needs to handle an exception differently, it can have its own set of local exception handlers that are checked before the global set.Local exceptions are usually specified in the Struts configuration file. Seechapter 4 for details.7.4 Rolling your own ActionMappingWhile ActionMapping provides an impressive array of properties, developers may also provide their own subclass with additional properties or methods. InStruts 1.0, this is configured in the deployment descriptor (web.xml) for the ActionServlet:<init-param><param-name>mapping</param-name><param-value>app.MyActionMapping</param-value></init-param>In Struts 1.1, this is configured in the Struts configuration file as an attribute to the <action-mappings> element:<action-mappings type="app.MyActionMapping">Individual mappings may also be set to use another type through the className attribute:<action className="app.MyActionMapping">For more about configuring Struts, see chapter 4.SinceStruts 1.1Summary 205The framework provides two base ActionMapping classes, shown in table 7.2. They can be selected as the default or used as a base for your own subclasses.The framework default is SessionActionMapping, so scope defaults to session. Subclasses that provide new properties may set them in the Struts configuration using a standard mechanism:<set-property property="myProperty" value="myValue" /> Using this standard mechanism helps developers avoid subclassing the Action- Servlet just to recognize the new properties when it digests the configuration file. This is actually a feature of the Digester that Struts simply inherits.7.5 SummarySun’s Model 2 architecture teaches that servlets and JavaServer Pages should be used together in the same application. The servlets can handle flow control and data acquisition, and the JavaServer Pages can handle the HTML.Struts takes this one step further and delegates much of the flow control anddata acquisition to Action objects. The application then needs only a single servletto act as a traffic cop. All the real work is parceled out to the Actions and theStruts configuration objects.Like servlets, Actions are efficient, multithreaded singletons. A single Actionobject can be handling any number of requests at the same time, optimizing your server’s resources.To get the most use out of your Actions, the ActionMapping object is used as a decorator for the Action object. It gives the Action a URI, or several URIs, and away to pass different configuration settings to an Action depending on which URIis called.In this chapter, we took a close look at the ActionMapping properties andexplained each property’s role in the scheme of things. We also looked at extendingthe standard ActionMapping object with custom properties—just in case yourscheme needs even more things.Table 7.2 The default ActionMapping classesActionMapping Descriptionorg.apache.struts.action.SessionActionMapping Defaults the scope property to sessionorg.apache.struts.action.RequestActionMapping Defaults the scope property to request206 CHAPTER 7Designing with ActionMappingsIn chapter 8, the real fun begins. The configuration objects covered so far aremainly a support system. They help the controller match an incoming requestwith a server-side operation. Now that we have the supporting players, let’s meet the Struts diva: the Action object.7.1 进入ActionMappingModel 2 架构(第1章)鼓励在同一个应用中使用servlet和JSP页面。
计算机专业毕业设计论文外文文献中英文翻译——java对象
1 . Introduction To Objects1.1The progress of abstractionAll programming languages provide abstractions. It can be argued that the complexity of the problems you’re able to solve is directly related to the kind and quality of abstraction。
By “kind” I mean，“What is it that you are abstracting?” Assembly language is a small abstraction of the underlying machine. Many so—called “imperative” languages that followed （such as FORTRAN，BASIC, and C) were abstractions of assembly language。
These languages are big improvements over assembly language，but their primary abstraction still requires you to think in terms of the structure of the computer rather than the structure of the problem you are trying to solve。
The programmer must establish the association between the machine model (in the “solution space，” which is the place where you’re modeling that problem, such as a computer) and the model of the problem that is actually being solved (in the “problem space,” which is the place where the problem exists). The effort required to perform this mapping, and the fact that it is extrinsic to the programming language，produces programs that are difficult to write and expensive to maintain，and as a side effect created the entire “programming methods” industry.The alter native to modeling the machine is to model the problem you’re trying to solve。
计算机中英论文
Understanding Web Addresses You can think of the World Wide Web as a network of electronic files stored on computers all around the world. Hypertext links these
news - a newsgroup
Ø telnet - a computer system that you can log into over the Internet Ø WAIS - a database or document in a Wide Area Information Search database Ø file - a file located on a local drive (your hard drive)
1
resources together. Uniform Resource Locators or URLs are the addresses used to locate these files. The information contained in a URL gives you the ability to jump from one web page to another with just a click of your mouse. When you type a URL into your browser or click on a hypertext link, your browser is sending a request to a remote computer to download a file. What does a typical URL look like? Here are some examples: / The home page for study English. ftp:///pub/ A directory of files at MIT available for downloading. news:rec.gardens.roses A newsgroup on rose gardening. The first part of a URL (before the two slashes* tells you the type of resource or method of access at that address. For example: Ø Ø Ø files Ø http - a hypertext document or directory gopher - a gopher document or menu ftp - a file available for downloading or a directory of such
计算机专业英语翻译
Computers are machines that can be used for performing calculations automatically.They can perform complex and repetitive procedures quickly, precisely and reliably and can quickly store and retrieve large amounts of data.电脑是机器可用来自动执行计算。
他们能够快速进行复杂的和重复的程序，精确可靠，可以快速存储和检索大量数据。
The physical components from which a computer is constructed (electronic circuits and input/output devices) are known as "hardware". Most computers have four types of hardware components: input, processor, storage (main memory, auxiliary storage) and output.身体成分构造计算机（电子电路和输入/输出设备）被称为“硬件”。
大部分的电脑有四种类型的硬件组成部分：输入，处理器，存储器（主存储器，辅助存储）和输出。
Input and output (I/O) devices allow the computer to communicate with the user and the outside world. The CPU (central processing unit) executes programs ("software") which tell the computer what to do.The two principal characteristics of a computer are: It responds to a specific set of instructions in a well-defined manner. It can execute a prerecorded list of instructions (a program).输入输出（I/O）设备允许计算机与用户和外界沟通。
计算机专业中英文文献翻译
1In the past decade the business environment has changed dramatically. The world has become a small and very dynamic marketplace. Organizations today confront new markets, new competition and increasing customer expectations. This has put a tremendous demand on manufacturers to; 1) Lower total costs in the complete supply chain 2) Shorten throughput times 3) Reduce stock to a minimum 4) Enlarge product assortment 5) Improve product quality 6) Provide more reliable delivery dates and higher service to the customer 7) Efficiently coordinate global demand, supply and production. Thus today's organization have to constantly re-engineer their business practices and procedures to be more and more responsive to customers and competition. In the 1990's information technology and business process re-engineering, used in conjunction with each other, have emerged as important tools which give organizations the leading edge.ERP Systems EvolutionThe focus of manufacturing systems in the 1960's was on inventory control. Most of the software packages then (usually customized) were designed to handle inventory based on traditional inventory concepts. In the 1970's the focus shifted to MRP (Material Requirement Planning) systems which translatedthe Master Schedule built for the end items into time-phased net requirements for the sub-assemblies, components and raw materials planning and procurement,In the 1980's the concept of MRP-II (Manufacturing Resources Planning) evolved which was an extension of MRP to shop floor and distribution management activities. In the early 1990's, MRP-II was further extended to cover areas like Engineering, Finance, Human Resources, Projects Management etc i.e. the complete gamut of activities within any business enterprise. Hence, the term ERP (Enterprise Resource Planning) was coined.In addition to system requirements, ERP addresses technology aspects like client/server distributedarchitecture, RDBMS, object oriented programming etc. ERP Systems-Bandwidth ERP solutions address broad areas within any business like Manufacturing, Distribution, Finance, Project Management, Service and Maintenance, Transportation etc. A seamless integration is essential to provide visibility and consistency across the enterprise.An ERP system should be sufficiently versatile to support different manufacturing environments like make-to-stock, assemble-to-order and engineer-to-order. The customer order decoupling point (CODP) should be flexible enough to allow the co-existence of these manufacturing environments within the same system. It is also very likely that the same product may migrate from one manufacturing environment to another during its produce life cycle.The system should be complete enough to support both Discrete as well as Process manufacturing scenario's. The efficiency of an enterprise depends on the quick flow of information across the complete supply chain i.e. from the customer to manufacturers to supplier. This places demands on the ERP system to have rich functionality across all areas like sales, accounts receivable, engineering, planning, inventory management, production, purchase, accounts payable, quality management, distribution planning and external transportation. EDI (Electronic Data Interchange) is an important tool in speeding up communications with trading partners.More and more companies are becoming global and focusing on down-sizing and decentralizing their business. ABB and Northern Telecom are examples of companies which have business spread around the globe. For these companies to manage their business efficiently, ERP systems need to have extensive multi-site management capabilities. The complete financial accounting and management accounting requirementsof the organization should be addressed. It is necessary to have centralized or de-centralized accounting functions with complete flexibility to consolidate corporate information.After-sales service should be streamlined and managed efficiently. A strong EIS (Enterprise Information System) with extensive drill down capabilities should be available for the top management to get a birds eye view of the health of their organization and help them to analyze performance in key areas.Evaluation CriteriaSome important points to be kept in mind while evaluating an ERP software include: 1) Functional fit with the Company's business processes 2) Degree of integration between the various components of the ERP system 3) Flexibility and scalability 4) Complexity; user friendliness 5) Quick implementation; shortened ROI period 6) Ability to support multi-site planning and control 7) Technology; client/server capabilities, database independence, security 8)Availability of regular upgrades 9) Amount of customization required 10) Local support infrastructure II) Availability of reference sites 12) Total costs,including cost of license, training, implementation, maintenance, customization and hardware requirements.ERP Systems-ImplementationThe success of an ERP solution depends on how quick the benefits can be reaped from it. This necessitates rapid implementations which lead to shortened ROI periods. Traditional approach to implementation has been to carry out a Business Process Re-engineering exercise and define a "TO BE"model before the ERP system implementation. This led to mismatches between the proposed model and the ERP functionality, the consequence of which was customizations, extended implementation time frames, higher costs and loss of user confidence.ERP Systems-The FutureThe Internet represents the next major technology enabler which allows rapid supply chain management between multiple operations and trading partners. Most ERP systems are enhancing their products to become "Internet Enabled" so that customers worldwide can have direct to the supplier's ERP system. ERP systems are building in the Workflow Management functionally which provides a mechanism to manage and controlthe flow of work by monitoring logistic aspects like workload, capacity, throughout times, work queue lengths and processing times.译文1在过去十年中，商业环境发生了巨大的变化。
中英文文献翻译
Database introduction and ACCESS2000The database is the latest technology of data management, and the important branch of computer science. The database , as its name suggests, is the warehouse to preserve the data. The warehouse to store apparatus in computer only, and data to deposit according to sure forms。
The so-called database is refers to the long-term storage the data acquisition which in the computer, organized, may share。
In the database data according to the certain data model organization, the description, and the storage, has a smaller redundance, the higher data independence and the easy extension, and may altogether shine for each kind of user。
The effective management database, frequently has needed some database management systems (DBMS) is the user provides to database operation each kind of order, the tool and the method, including database establishment and recording input, revision, retrieval, demonstration, deletion and statistics。
毕业设计论文外文文献翻译计算机科学与技术微软VisualStudio中英文对照
外文文献翻译（2012届）学生姓名学号********专业班级计算机科学与技术08-5班指导教师微软Visual Studio1微软Visual StudioVisual Studio 是微软公司推出的开发环境，Visual Studio可以用来创建Windows平台下的Windows应用程序和网络应用程序，也可以用来创建网络服务、智能设备应用程序和Office 插件。
Visual Studio是一个来自微软的集成开发环境IDE（inteqrated development environment），它可以用来开发由微软视窗，视窗手机，Windows CE、.NET框架、.NET精简框架和微软的Silverlight支持的控制台和图形用户界面的应用程序以及Windows窗体应用程序，网站，Web应用程序和网络服务中的本地代码连同托管代码。
Visual Studio包含一个由智能感知和代码重构支持的代码编辑器。
集成的调试工作既作为一个源代码级调试器又可以作为一台机器级调试器。
其他内置工具包括一个窗体设计的GUI应用程序，网页设计师，类设计师，数据库架构设计师。
它有几乎各个层面的插件增强功能，包括增加对支持源代码控制系统（如Subversion和Visual SourceSafe）并添加新的工具集设计和可视化编辑器，如特定于域的语言或用于其他方面的软件开发生命周期的工具（例如Team Foundation Server的客户端：团队资源管理器）。
Visual Studio支持不同的编程语言的服务方式的语言，它允许代码编辑器和调试器（在不同程度上）支持几乎所有的编程语言，提供了一个语言特定服务的存在。
内置的语言中包括C/C + +中（通过Visual C++）,（通过Visual ），C＃中（通过Visual C＃）和F＃（作为Visual Studio 2010），为支持其他语言，如M,Python,和Ruby等，可通过安装单独的语言服务。
计算机专业英语翻译
●计算机专业英语翻译部分●Data is a collection of un-organized facts, which can include words, numbers, images, andsounds.●数据是未经组织的事实的集合,数据可以包括单词,数字,图像和声音.● A computer consists of a variety of hardware components that work together with software toperform calculations（计算）, organize data, and communicate with other computer.●计算机由许多硬件部件构成,这些硬件与软件一起工作,以便执行计算,组织数据及与其他计算机通信的任务.●These hardware components include input devices, output devices, a system unit, storagedevices, and communications devices.●硬件部件包括输入设备,输出设备,系统单元,存储设备和通信设备.●An input device allows a user to enter data and commands into the memory of a computer.●输入设备让用户向计算机存储器输入数据和命令.●Storage differs from memory ,which can hold these items permanently(永久的)，whereasmemory holds these memory holds items only temporarily(暂时的)。
●外存储器与内存储器不同,外存储器能永久保存数据而内存储器仅临时保存.●Four common storage devices are a floppy disk drive, a hard disk drive, a CD-ROM drive, and aDVD-ROM drive.●四种常用的外存设备分别是:软盘驱动器,硬盘驱动器,CD-ROM驱动器和DVD-ROM驱动器.●Television?and?data?can?be?mixed?on?one?cable.?●宽带能用于多个方面。
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OverviewWhen ASP was first released,Web programming was more difficult because you needed IIS to serve your ASP ter,2.0and Visual Studio®2005made everything easier by introducing the Web site model of development.Instead of creating a new project inside Visual Studio,the Web site model lets you point to a directory and start writing pages and code.Furthermore,you can quickly test your site with the built-in Development Server,which hosts in a local process and obviates the need to install IIS to begin developing.we will introduce 2.0technology from different aspects. Framework Class Library is part of Microsoft's framework,which contains a vast set of programming classes designed to satisfy any conceivable programming need.Because Visual Basic,JScript,and C++.A great deal of the functionality of these programming languages overlaps.For example,for each language,you would have to include methods for accessing the file system,working with databases,and manipulating strings.What’s more, these languages contain similar programming constructs,can represent loops and conditionals.Even though the syntax of a conditional written in Visual Basic differs from the syntax of a conditional written in C++,the programming function is the same. Maintaining all this functionality for multiple languages requires a lot of work.Wouldn't it be easier to create all this functionality once and use it for every language?However, Framework Class Library does exactly that.It consists of a vast set of classes designed to satisfy any conceivable programming need.For instance, framework contains classes for handling database access,working with the file system,manipulating text,and generating graphics.In addition,it contains more specialized classes for performing tasks such as working with regular expressions and handling network protocols. Furthermore, framework contains classes that represent all the basic variable data types such as strings,integers,bytes,characters,and arrays. framework is huge.It contains thousands of classes(over3,400). Fortunately,the classes are not simply jumbled together.The classes of framework are organized into a hierarchy of namespaces.A namespace is a logical grouping of classes.For example,all the classes that relate to working with the file system are gathered together into the System.IO namespace.The namespaces are organized into a hierarchy(a logical tree).At the root of the tree is the System namespace.This namespace contains all the classes for the base data types,such as strings and arrays.It also contains classes for working with random numbers and dates and times.You can uniquely identify any class in framework by using the full namespace of the class.For example,to uniquely refer to the class that represents a file system file(the File class),you would use the following:System.IO.FileSystem.IO refers to the namespace,and File refers to the particular class.The classes contained in a select number of namespaces are available in your pages by default.(You must explicitly import other namespaces.)These default namespaces contain classes that you use most often in your applications: System—Contain all the base data types and other useful classes such as those related to generating random numbers and working with dates and times.System.Collections—Contains classes for working with standard collection types such as hash tables,and array lists.System.Collections.Specialized—Contains classes that represent specialized collections such as linked lists and string collections.System.Configuration—Contains classes for working with configuration files (Web.config files).System.Text—Contains classes for encoding,decoding,and manipulating the contents of strings.System.Text.RegularExpressions—Contains classes for performing regular expression match and replace operations.System.Web—Contain the basic classes for working with the World Wide Web, including classes for representing browser requests and server responses.System.Web.Caching—Contains classes used for caching the content of pages and classes for performing custom caching operations.System.Web.Security—Contains classes for implementing authentication and authorization such as Forms and Passport authentication.System.Web.SessionState—Contains classes for implementing session state.System.Web.UI—Contain the basic classes used in building the user interface of pages.System.Web.UI.HTMLControls—Contain the classes for the HTML controls.System.Web.UI.WebControls—Contain the classes for the Web controls.You can choose C#or or C++or Visual Basic to program page. regardless of the language that you use to develop your pages,you need to understand that pages are compiled before they are executed.This means that pages can execute very quickly.The first time you request an page,the page is compiled into class,and the resulting class file is saved beneath a special directory on your server named Temporary Files.For each and every page,a corresponding class file appears in the Temporary Files directory. Whenever you request the same page in the future,the corresponding class file is executed.When an page is compiled,it is not compiled directly into machine code.Instead,it is compiled into an intermediate-level language called Microsoft Intermediate Language(MSIL)-compatible languages are compiled into this intermediate language.An page isn't compiled into native machine code until it is actually requested by a browser.At that point,the class file contained in the Temporary Files directory is compiled with framework Just in Time(JIT)compiler and executed.The magical aspect of this whole process is that it happens automatically in the background.All you have to do is create a text file with the source code for your page.2.Building Forms with Web Server ControlsUsingseveral of the basic Web controls to represent standard HTML form elements such as radio buttons,text boxes,and list boxes.You can use these controls in your pages to create the user interface for your Web application.3.Performing Form Validation with Validation ControlsTraditionally,Web developers have faced a tough choice when adding form validation logic to their pages.You can add form validation routines to your server-side code,or you can add the validation routines to your client-side code.The advantage of writing validation logic in client-side code is that you can provide instant feedback to your users.For example,if a user neglects to enter a value in a required form field,you can instantly display an error message without requiring a roundtrip back to the server.People really like client-side validation.It looks great and creates a better overall user experience. The problem,however,is that it does not work with all browsers.Not all browsers support JavaScript,and different versions of browsers support different versions of JavaScript,so client-side validation is never guaranteed to work.For this reason,in the past,many developers decided to add all their form validation logic exclusively to server-side code. Because server-side code functions correctly with any browser,this course of action was safer.At the same time,The Validation controls automatically generate both client-side and server-side code.If a browser is capable of supporting JavaScript,client-side validation scripts are automatically sent to the browser.If a browser is incapable of supporting JavaScript,the validation routines are automatically implemented in server-side code.Requiring Fields:The RequiredFieldValidator ControlYou use RequiredFieldValidator in a Web form to check whether a control has a value.Typically,you use this control with a TextBox control.However,nothing is wrong with using RequiredFieldValidator with other input controls such as RadioButtonList.Validating Expressions:The RegularExpressionValidator ControlYou can use RegularExpressionValidator to match the value entered into a form field to a regular expression.You can use this control to check whether a user has entered,for example,a valid e-mail address,telephone number,or username or password.Samples of how to use a regular expression to perform all these validation tasks are provided in the following sections.Comparing Values:The CompareValidator ControlThe CompareValidator control performs comparisons between the data entered into a form field and another value.The other value can be a fixed value,such as a particular number,or a value entered into another control.Summarizing Errors:The ValidationSummary ControlImagine that you have a form with50form fields.If you use only the Validation controls discussed in the previous sections of this chapter to display errors,seeing an error message on the page might be difficult.For example,you might have to scroll down to the 48th form field to find the error message.Fortunately,Microsoft includes a ValidationSummary control with the Validation controls.You can use this control to summarize all the errors at the top of a page,or wherever else you want.4.Advanced Control ProgrammingWorking with View StateBy default,almost all controls retain the values of their properties between form posts.For example,if you assign text to a Label control and submit the form,when the page is rendered again,the contents of the Label control are preserved.The magic of view state is that it does not depend on any special server or browser properties.In particular,it does not depend on cookies,session variables,or application variables.View state is implemented with a hidden form field called VIEWSTATE that is automatically created inevery Web Forms Page.When used wisely,view state can have a dramatic and positive effect on the performance of your Web site.For example,if you display database data in a control that has view state enabled,you do not have to return to the database each time the page is posted back to the server.You can automatically preserve the data within the page's view state between form posts.Displaying and Hiding ContentImagine that you want to break the tax form into multiple pages so that a person views only one part of the tax form at a time.You can set the Visible and Enabled properties with individual controls and groups of controls to hide and display page ing the Visible and Enabled PropertiesEvery control,including both HTML and Web controls,has a visible property that determines whether the control is rendered.When a control's visible property has the value False,the control is not displayed on the page;the control is not processed for either pre-rendering or rendering.Web controls(but not every HTML control)have an additional property named Enabled.When Enabled has the value False and you are using Internet Explorer version4.0or higher,the control appears ghosted and no longer functions.When used with other browsers, such as Netscape Navigator,the control might not appear ghosted,but it does not function.5.Web Deployment ProjectsThe beauty of the 2.0is that you can develop your Web application without thinking about packaging and deployment.When need another class,You can Add a.Cs file to the App_Code directory and start writing.When want to store localizable strings in a resource file,you can add a.resx file to the App_GlobalResources directory and type in the strings.Everything just works;you don't have to think about the compilation and deployment aspect at all.When you are ready to deploy,you have several options.The simplest choice is to copy your files to a live server and let everything be compiled on-demand(as it was in your test environment).The second option is to use the aspnet_compiler.exe utility andprecompile the application into a binary release,which leaves you nothing but a collection of assemblies,static content,and configuration files to push to the server.The third option is to again use aspnet_compiler.exe,but to create an updateable binary deployment where your.as*x files remain intact(and modifiable)and all of your code files are compiled into binary assemblies.6.C#LanguageIntroduction to the C#Language and Framework C#is an elegant and type-safe object-oriented language that enables developers to build a wide range of secure and robust applications that run on Framework.You can use C#to create traditional Windows client applications,XML Web services,distributed components, client-server applications,database applications,and much,much more.Microsoft Visual C#2005provides an advanced code editor,convenient user interface designers,integrated debugger,and many other tools to facilitate rapid application development based on version 2.0of the C#language and Framework.C#syntax is highly expressive,yet with less than90keywords,it is also simple and easy to learn.The curly-brace syntax of C#will be instantly recognizable to anyone familiar with C,C++or Java.Developers who know any of these languages are typically able to begin working productively in C#within a very short time.C#syntax simplifies many of the complexities of C++while providing powerful features such as nullable value types, enumerations,delegates,anonymous methods and direct memory access,which are not found in Java.C#also supports generic methods and types,which provide increased type safety and performance,and iterators,which enable implementers of collection classes to define custom iteration behaviors that are simple to use by client code.As an object-oriented language,C#supports the concepts of encapsulation,inheritance and polymorphism.All variables and methods,including the Main method,the application's entry point,are encapsulated within class definitions.A class may inherit directly from one parent class,but it may implement any number of interfaces.Methods that override virtual methods in a parent class require the override keyword as a way to avoid accidentalredefinition.In C#,a struct is like a lightweight class;it is a stack-allocated type that can implement interfaces but does not support inheritance.In addition to these basic object-oriented principles,C#facilitates the development of software components through several innovative language constructs,including:∙Encapsulated method signatures called delegates,which enable type-safe event notifications.∙Properties,which serve as accessors for private member variables.∙Attributes,which provide declarative metadata about types at run time.∙Inline XML documentation comments.If you need to interact with other Windows software such as COM objects or native Win32DLLs,you can do this in C#through a process called"Interop."Interop enables C# programs to do just about anything that a native C++application can do.C#even supports pointers and the concept of"unsafe"code for those cases in which direct memory access is absolutely critical.The C#build process is simple compared to C and C++and more flexible than in Java. There are no separate header files,and no requirement that methods and types be declared in a particular order.A C#source file may define any number of classes,structs,interfaces, and events.C#programs run on Framework,an integral component of Windows that includes a virtual execution system called the common language runtime(CLR)and a unified set of class libraries.The CLR is Microsoft's commercial implementation of the common language infrastructure(CLI),an international standard that is the basis for creating execution and development environments in which languages and libraries work together seamlessly.Source code written in C#is compiled into an intermediate language(IL)that conforms to the CLI specification.The IL code,along with resources such as bitmaps and strings,isstored on disk in an executable file called an assembly,typically with an extension of.exe or.dll.An assembly contains a manifest that provides information on the assembly's types, version,culture,and security requirements.When the C#program is executed,the assembly is loaded into the CLR,which might take various actions based on the information in the manifest.Then,if the security requirements are met,the CLR performs just in time(JIT)compilation to convert the IL code into native machine instructions.The CLR also provides other services related to automatic garbage collection,exception handling,and resource management.Code that is executed by the CLR is sometimes referred to as"managed code,"in contrast to "unmanaged code"which is compiled into native machine language that targets a specific system.The following diagram illustrates the compile-time and run time relationships of C# source code files,the base class libraries,assemblies,and the CLR.Language interoperability is a key feature of Framework.Because the IL code produced by the C#compiler conforms to the Common Type Specification(CTS),IL code generated from C#can interact with code that was generated from versions of Visual Basic,Visual C++,Visual J#,or any of more than20other CTS-compliant languages.A single assembly may contain multiple modules written in languages,and the types can reference each other just as if they were written in the same language.In addition to the run time services, Framework also includes an extensive library of over4000classes organized into namespaces that provide a wide variety of useful functionality for everything from file input and output to string manipulation to XML parsing,to Windows Forms controls.The typical C#application uses Framework class library extensively to handle common"plumbing"chores.概述当ASP第一次发布时，Web编程还比较困难，因为需要IIS来处理ASP页。