restful WebService的入门例子

研究了两天CXF对restful的支持。

现在，想实现一个以http://localhost:9999/roomservice 为入口，http://localhost:9999/roomservice/room为房间列表,http://localhost:9999/roomservice/room/001/ 为001号房间的信息，http://localhost:9999/roomservice/room/001/person 为在001号房间主的人的列表实现用HTTP请求对以上资源的CRUD。

首先建立room,person的POJO，这里只有一点需要注意：package com.DAO;import javax.xml.bind.annotation.XmlRootElement;@XmlRootElement(name="Person")public class Person {private String name;private String sex;public String getName() {return name;}public void setName(String name) { = name;}public String getSex() {return sex;}public void setSex(String sex) {this.sex = sex;}}一定要在类的前边加上annotation ，这样才能让这个person的信息在POJO和XML之间转换。

Room同理:import java.util.Map;import javax.xml.bind.annotation.XmlRootElement;@XmlRootElement(name="Room")public class Room {public Room(){persons=new HashMap<String,Person>();}String id;Map<String,Person> persons;public String getId() {return id;}public void setId(String id) {this.id = id;}public Map<String, Person> getPersons() {return persons;}public void setPersons(Map<String, Person> persons) { this.persons = persons;}}POJO有了，接下来要写DAO，由于主要是为了学习restful，为了方便，不必要将数据持久化到数据库，而是存在一个静态的HashMap中：package com.DAO;import java.util.HashMap;import java.util.Map;public class RoomDAO {private static Map<String, Room> rooms;static {rooms = new HashMap<String, Room>();Person p1=new Person();p1.setName("Boris");p1.setSex("male");Room r=new Room();r.setId("001");r.getPersons().put(p1.getName(), p1);rooms.put("001", r);}public static void addRoom(Room room) {rooms.put(room.getId(), room);}public static void deleteRoom(String id) {if (rooms.containsKey(id)) {rooms.remove(id);}}public static void updateRoom(String id,Room room) {rooms.remove(id);rooms.put(room.getId(), room);}public static Room getRoom(String id) {if (rooms.containsKey(id)) {return rooms.get(id);} else {return null;}}/*operations to persons*/public static void addPerson(String id_room,Person person) { if(rooms.containsKey(id_room)){Room room=rooms.get(id_room);room.getPersons().put(person.getName(), person);}}public static Rooms getRooms(){return new Rooms();}public static void deletePerson(String id_room,String name) {if(rooms.containsKey(id_room)){Room room=rooms.get(id_room);room.getPersons().remove(name);}}public static Map<String, Room> getMapOfRooms(){return rooms;}}接下来是重点，如果想发布restful webservice，要通过一个叫JAXRSServerFactoryBean 的类来发布。

这个类有几个方法是要了解的：public void setResourceClasses(Class... classes);那一系列的Class类型的参数，是告诉这个类，发布服务时，会用到的POJO（就像上边写的Room,Person）。

public void setAddress(String address)；这个方法是告诉这个类，服务的地址，比如"http://localhost:9999"public void setServiceBeans(Object... beans)这里是重点，这个方法，要给这个用来发布服务的类一个Service bean.这个Bean是我们要手动编写的，作用是告诉服务，收到什么样的请求，应该怎么样处理。

现在，先来编写这个Service bean：package com.server;import javax.ws.rs.Consumes;import javax.ws.rs.DELETE;import javax.ws.rs.GET;import javax.ws.rs.POST;import javax.ws.rs.PUT;import javax.ws.rs.Path;import javax.ws.rs.PathParam;import javax.ws.rs.Produces;import com.DAO.Person;import com.DAO.Room;import com.DAO.RoomDAO;import com.DAO.Rooms;@Path("/roomservice")@Produces("application/xml")public class RoomService {@GET@Path("/room/{id}")@Consumes("application/xml")public Room getRoom(@PathParam("id")String id ){System.out.println("get room by id= "+id);Room room=RoomDAO.getRoom(id);return room;}@GET@Path("/room")@Consumes("application/xml")public Rooms getAllRoom(){System.out.println("get all room");Rooms rooms=RoomDAO.getRooms();return rooms;}@POST@Path("/room")@Consumes("application/xml")public void addRoom(Room room){System.out.println("add room which id is:"+room.getId()); RoomDAO.addRoom(room);}@PUT@Path("/room/{id}")@Consumes("application/xml")public void updateRoom(@PathParam("id")String id,Room room) {System.out.println("update room which original idis:"+room.getId());RoomDAO.updateRoom(id,room);}@DELETE@Path("/room/{id}")@Consumes("application/xml")public void deleteRoom(@PathParam("id")String id){System.out.println("remove room by id= "+id);RoomDAO.deleteRoom(id);}@POST@Path("/room/{id}")@Consumes("application/xml")public void addPerson(@PathParam("id") String id,Person person) {System.out.println("add person who's nameis:"+person.getName());RoomDAO.addPerson(id, person);}@DELETE@Path("/room/{id}/{name}")@Consumes("application/xml")public void deletePerson(@PathParam("id")Stringid,@PathParam("name")String name){System.out.println("remove person who's name is: "+name); RoomDAO.deletePerson(id, name);}}需要注意：每个方法之前，要用annotation声明http请求的method类型，比如GET,DELETE,POST, PUT.@Produces("application/xml")我还没弄清楚到底是声明的接受格式还是返回格式，还是其他。