java课程设计报告(完整版)

目录1、摘要2、概要设计3、详细设计4、测试分析5、总结6、参考文献【前言】Java不依赖平台的特点使得它受到广泛的关注，Java已成为网络时代最重要的语言之一。

Java语言不仅是一门正在被广泛使用的编程语言，而且已成为软件设计开发者应当掌握的一门基础语言。

目前，很多新的技术领域都涉及Java语言，国内外许多大学已将Java语言列入了本科教学计划，掌握Java已经成为共识。

本次课程设计就是利用java语言来编写简单的计算器，能进行加、减、乘、除四则运算，下面给出了该设计的理论分析和具体步骤。

一、摘要本计算器可以进行简单的四则运算（加、减、乘、除），但仅限于十进制下。

“Backspace”按钮表示退格，“CE”按钮表示清除当前文本框内的数据，“C”按钮表示清除文本框内数据，同时var、answer清零。

该程序可在JCreator环境下直接运行。

二、概要设计1、自定义说明（1）类名：Calculator作用：主类继承的父类：JFrame类实现的接口：ActionListener类public class Calculator extends JFrame implements ActionListener{private static String[] btnTexts = {"0","1","2","3","4","5","6","7","8","9","+","-","*","/",".","+/-"}; //定义数组bstTexts来存放计算器上的各个按钮Button button[] = new Button[16];Button BkButton,CeButton,CButton,EqButton;boolean clickable; //控制当前能否按键double vard, answerd; //用来保存double型数据的中间值(vard)和最后结果(answerd)short key = -1, prekey = -1; //key用来保存当前进行何种运算,prekey用来保存前次进行何种运算DecimalFormat df; //设置数据输出精度private JTextField displayField = new JTextField(" "); //计算结果显示区public Calculator(){………}public void actionPerformed(ActionEvent event){………}}(2)方法名：Calculator作用：设置窗体布局public Calculator(){//Frame frame = new Frame("Calculator");super("Calculator"); //显示主窗口标题“Calculator”df = new DecimalFormat("0.00000000"); //设置数据输出精度(对于double型值)BkButton = new Button("Backspace");BkButton.setForeground(Color.red);CeButton = new Button("CE");tForeground(Color.red);CButton = new Button("C");CButton.setForeground(Color.red);EqButton = new Button("=");EqButton.setForeground(Color.red); //将“Backspace”、“CE”、”C”、“=”显示为红色BkButton.addActionListener(this);nListener(this);CButton.addActionListener(this);EqButton.addActionListener(this);displayField.setHorizontalAlignment(JTextField.RIGHT); //将计算结果显示在displayField的右面JPanel p1 = new JPanel(new FlowLayout()); //以FlowLayout布局p1 p1.add(BkButton);p1.add(CeButton);p1.add(CButton);p1.add(EqButton); //设置四个按钮:"Backspace","CE","C","="JPanel p2 = new JPanel(new GridLayout(2,1)); //以GridLayout布局p2 p2.add(displayField);p2.add(p1); //加入显示结果的JTextField和p1JPanel p3 = new JPanel(new GridLayout(4,4)); //以GridLayout布局p3 for(int i = 0;i < btnTexts.length;i++){button[i] = new Button(btnTexts[i]); //将数组btnTexts[]的值赋给数组button[] button[i].setForeground(Color.blue); //组件button的前景色显示蓝色p3.add(button[i]);button[i].addActionListener(this);}Container cp = this.getContentPane(); //采用默认的BorderLayout布局cpcp.add(p2,BorderLayout.NORTH);R);}（3）方法名：actionPerformed作用：设置各个按钮的行为public void actionPerformed(ActionEvent event){boolean sign = false; //判断是否是double型数参与运算，是为true，不是为falseObject temp = event.getSource();try{for (int i = 0; i <= 9; i++) //如果按下数据按钮，将按下的按钮代表的数据插入的当前文本框字符串之后displayField.setText(displayField.getText() + Integer.toString(i));//按下'.'按钮时，判断当前文本框内字符串中含不含'.'，如果已含，则不允许再插入'.'if (temp == button[14] && clickable == true){……….}if ( (temp == button[10] || temp == button[11] || temp == button[12] || temp == button[13]) && clickable == true){//'+'操作if (temp == button[10]){…………}//'-'操作if (temp == button[11]){…………}//'*'操作if (temp == button[12]){…………}//'/'操作if (temp == button[13]){…………}//'='操作if (temp == EqButton && clickable == true){…………}//按下'+/-'按钮时处理{…………}//按下'Backspace'键，利用循环将当前字符串中的最后一个字母删除if (temp == BkButton && clickable == true){…………}//按下'CE'按钮，将当前文本框内数据清除if (temp == CeButton){………}//按下'C'按钮，文本框内数据清除，同时var,answer清0if (temp == CButton){………}}//输入中如果有操作非法，比如按下两次'+'，捕获异常catch (Exception e){displayField.setText("操作非法");clickable = false;}2、界面设计下图为该程序运行时的界面截图：三、详细设计以下为该程序的主要代码：import javax.swing.*;import java.awt.*;import javax.swing.event.*;import java.awt.event.*;imalFormat;public class Calculator extends JFrame implements ActionListener{private static String[] btnTexts ={"0","1","2","3","4","5","6","7","8","9","+","-","*","/",".","+/-"};Button button[] = new Button[16];Button BkButton,CeButton,CButton,EqButton;boolean clickable; //控制当前能否按键double vard, answerd; //用来保存double型数据的中间值(vard)和最后结果(answerd)short key = -1, prekey = -1; //key用来保存当前进行何种运算,prekey用来保存前次进行何种运算DecimalFormat df; //设置数据输出精度private JTextField displayField = new JTextField(" ");//计算结果显示区public Calculator(){super("Calculator"); //显示主窗口标题“Calculator”df = new DecimalFormat("0.00000000"); //设置数据输出精度(对于double型值)BkButton = new Button("Backspace");BkButton.setForeground(Color.red);CeButton = new Button("CE");CeButton.setForeground(Color.red);CButton = new Button("C");CButton.setForeground(Color.red);EqButton = new Button("=");EqButton.setForeground(Color.red); //将“Backspace”、“CE”、”C”、“=”显示为红色BkButton.addActionListener(this);CeButton.addActionListener(this);CButton.addActionListener(this);EqButton.addActionListener(this);displayField.setHorizontalAlignment(JTextField.RIGHT); //将计算结果显示在displayField的右面JPanel p1 = new JPanel(new FlowLayout()); //以FlowLayout布局p1 p1.add(BkButton);p1.add(CeButton);p1.add(CButton);p1.add(EqButton); //设置三个按钮:"Backspace","CE","C","="JPanel p2 = new JPanel(new GridLayout(2,1)); //以GridLayout布局p2 p2.add(displayField);p2.add(p1); //加入显示结果的JTextField和p1JPanel p3 = new JPanel(new GridLayout(4,4)); //以GridLayout布局p3 for(int i = 0;i < btnTexts.length;i++){button[i] = new Button(btnTexts[i]); //将数组btnTexts[]的值赋给数组button[] button[i].setForeground(Color.blue); //组件button的前景色示蓝色p3.add(button[i]);button[i].addActionListener(this);}Container cp = this.getContentPane(); //采用默认的BorderLayout布局cpcp.add(p2,BorderLayout.NORTH);cp.add(p3,BorderLayout.CENTER);}//设置各个按钮行为public void actionPerformed(ActionEvent event){boolean sign = false; //判断是否是double型数参与运算，是为true，不是为falseObject temp = event.getSource();try{for (int i = 0; i <= 9; i++) //如果按下数据按钮，将按下的按钮代表的数据插入的当前文本框字符串之后if (temp == button[i] && clickable == true)displayField.setText(displayField.getText() + Integer.toString(i));//按下'.'按钮时，判断当前文本框内字符串中含不含'.'，如果已含，则不允许再插入'.'if (temp == button[14] && clickable == true){boolean isDot = false;if (displayField.getText().length() == 0)isDot = true;for (int i = 0; i < displayField.getText().length(); i++)if ('.' == displayField.getText().charAt(i)){isDot = true;break;}if (isDot == false)displayField.setText(displayField.getText() + ".");}if ( (temp == button[10] || temp == button[11] || temp == button[12] || temp == button[13]) && clickable == true){//'+'操作if (temp == button[10]){switch (prekey){case 0:answerd += Double.parseDouble(displayField.getText());break;case 1:answerd -= Double.parseDouble(displayField.getText());break;case 2:answerd *= Double.parseDouble(displayField.getText());break;case 3:if (Double.parseDouble(displayField.getText()) == 0){displayField.setText("除数不能为零");clickable = false;}elseanswerd /= Double.parseDouble(displayField.getText());break;default:le(displayField.getText());}displayField.setText("");prekey = key = 0;}//'-'操作if (temp == button[11]){switch (prekey){case 0:answerd += Double.parseDouble(displayField.getText());break;case 1:answerd -= Double.parseDouble(displayField.getText());break;case 2:answerd *= Double.parseDouble(displayField.getText());break;case 3:if (Double.parseDouble(displayField.getText()) == 0){displayField.setText("除数不能为零");clickable = false;}elseanswerd /= Double.parseDouble(displayField.getText());break;default:answerd = Double.parseDouble(displayField.getText());}displayField.setText("");prekey = key = 1;}//'*'操作if (temp == button[12]){switch (prekey){case 0:answerd += Double.parseDouble(displayField.getText());break;case 1:answerd -= Double.parseDouble(displayField.getText());break;case 2:answerd *= Double.parseDouble(displayField.getText());break;case 3:if (Double.parseDouble(displayField.getText()) == 0){displayField.setText("除数不能为零");clickable = false;}elseanswerd /= Double.parseDouble(displayField.getText());break;default:answerd = Double.parseDouble(displayField.getText());}displayField.setText("");prekey = key = 2;}//'/'操作if (temp == button[13]){switch (prekey){case 0:answerd += Double.parseDouble(displayField.getText());break;case 1:answerd -= Double.parseDouble(displayField.getText());break;case 2:answerd *= Double.parseDouble(displayField.getText());break;case 3:if (Double.parseDouble(displayField.getText()) == 0){displayField.setText("除数不能为零");clickable = false;}elseanswerd /= Double.parseDouble(displayField.getText());break;default:answerd = Double.parseDouble(displayField.getText());}displayField.setText("");prekey = key = 3;}}//'='操作if (temp == EqButton && clickable == true){//如果连续按'=',则进行连续运算if (prekey == 5){if (key == 0){answerd += vard;displayField.setText(df.format(answerd));}if (key == 1){answerd -= vard;displayField.setText(df.format(answerd));}if (key == 2){answerd *= vard;displayField.setText(df.format(answerd));}if (key == 3){if (Double.parseDouble(displayField.getText()) == 0){displayField.setText("除数不能为零");clickable = false;}else{answerd /= vard;displayField.setText(df.format(answerd));}}}else{vard = Double.parseDouble(displayField.getText());if (key == 0){prekey = -1;answerd += Double.parseDouble(displayField.getText());displayField.setText(df.format(answerd));}if (key == 1){prekey = -1;answerd -= Double.parseDouble(displayField.getText());displayField.setText(df.format(answerd));}if (key == 2){prekey = -1;answerd *= Double.parseDouble(displayField.getText());displayField.setText(df.format(answerd));}if (key == 3){prekey = -1;if (Double.parseDouble(displayField.getText()) == 0){displayField.setText("除数不能为零");clickable = false;}else{answerd /= Double.parseDouble(displayField.getText());displayField.setText(df.format(answerd));}}prekey = 5;}//按下'+/-'按钮时处理if (temp == button[15] && clickable == true){boolean isNumber = true;String s = displayField.getText();for (int i = 0; i < s.length(); i++)if (! (s.charAt(i) >= '0' && s.charAt(i) <= '9' || s.charAt(i) == '.' || s.charAt(i) == '-')){isNumber = false;break;}if (isNumber == true){//如果当前字符串首字母有'-'号,代表现在是个负数,再按下时,则将首符号去掉if (s.charAt(0) == '-'){displayField.setText("");for (int i = 1; i < s.length(); i++){char a = s.charAt(i);displayField.setText(displayField.getText() + a);}}//如果当前字符串第一个字符不是符号，则添加一个符号在首字母处elsedisplayField.setText('-' + s);}}//按下'Backspace'键，利用循环将当前字符串中的最后一个字母删除if (temp == BkButton && clickable == true)String s = displayField.getText();displayField.setText("");for (int i = 0; i < s.length() - 1; i++){char a = s.charAt(i);displayField.setText(displayField.getText() + a);}}//按下'CE'按钮，将当前文本框内数据清除if (temp == CeButton){displayField.setText("");clickable = true;}//按下'C'按钮，文本框内数据清除，同时var,answer清0if (temp == CButton){vard = answerd = 0;displayField.setText("");clickable = true;}}//输入中如果有操作非法，比如按下两次'+'，捕获异常catch (Exception e){displayField.setText("操作非法");clickable = false;}}public static void main(String args[]){Calculator calculator = new Calculator();calculator.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);calculator.setSize(300,200);calculator.setVisible(true);}}四、测试分析（1）程序运行情况该程序正常的响应按钮事件，能进行简单的加、减、乘、除四则运算，在输入之前须先进行清零处理，然后再输入数值进行运算。