用Jersey构建RESTful服务4--通过jersey-client客户端调用Jersey的Web服务模拟CURD

一、总体说明

通过jersey-client接口，创建客户端程序，来调用Jersey实现的RESTful服务，实现增、删、改、查等操作。

服务端主要是通过内存的方式，来模拟用户的增加、删除、修改、查询等操作。

二、创建服务端

1.在上文项目中，

在“com.waylau.rest.resources.UserResource“中修改代码，

首先创建一个HashMap，用来保存添加的用户

private static Map<String,User> userMap  = new HashMap<String,User>();

2.创建增、删、改、查 用户资源等操作

/** * 增加 * @param user */@POST    @Consumes({MediaType.APPLICATION_XML, MediaType.APPLICATION_JSON})    public void createStudent(User user)    {userMap.put(user.getUserId(), user );    }/** * 删除 * @param id */    @DELETE    @Path("{id}")    public void deleteStudent(@PathParam("id")String id){    userMap.remove(id);    }        /**     * 修改     * @param user     */    @PUT    @Consumes(MediaType.APPLICATION_XML)    public void updateStudent(User user){userMap.put(user.getUserId(), user );    }     /**     * 根据id查询     * @param id     * @return     */    @GET    @Path("{id}")    @Produces({MediaType.APPLICATION_XML, MediaType.APPLICATION_JSON})    public User getUserById(@PathParam("id") String id){    User u = userMap.get(id);    return u;    }       /**     * 查询所有     * @return     */    @GET    @Produces({MediaType.APPLICATION_XML, MediaType.APPLICATION_JSON})    public List<User> getAllUsers(){         List<User> users = new ArrayList<User>();           users.addAll( userMap.values() );          return users;    }    

三、创建客户端程序

1.创建包“com.waylau.rest.client”，在包下建一个UserClient.java，代码如下：

package com.waylau.rest.client;import javax.ws.rs.client.Client;import javax.ws.rs.client.ClientBuilder;import javax.ws.rs.client.Entity;import javax.ws.rs.client.WebTarget;import javax.ws.rs.core.MediaType;import javax.ws.rs.core.Response;import org.codehaus.jackson.jaxrs.JacksonJsonProvider;import com.waylau.rest.bean.User; /** * 用户客户端，用来测试资源 * @author waylau.com * 2014-3-18 */public class UserClient {private static String serverUri = "http://localhost:8089/RestDemo/rest";/** * @param args */public static void main(String[] args) {addUser();getAllUsers();updateUser();getUserById();getAllUsers();delUser();getAllUsers();}/** * 添加用户 */ private static void addUser() { System.out.println("****增加用户addUser****"); User user = new User("006","Susan","21");   Client client = ClientBuilder.newClient(); WebTarget target = client.target(serverUri + "/users"); Response response = target.request().buildPost(Entity.entity(user, MediaType.APPLICATION_XML)).invoke(); response.close();    } /** * 删除用户 */ private static void delUser() { System.out.println("****删除用户****"); Client client = ClientBuilder.newClient(); WebTarget target = client.target(serverUri + "/users/006"); Response response = target.request().delete(); response.close();}  /** * 修改用户 */ private static void updateUser() { System.out.println("****修改用户updateUser****"); User user = new User("006","Susan","33");   Client client = ClientBuilder.newClient(); WebTarget target = client.target(serverUri + "/users"); Response response = target.request().buildPut( Entity.entity(user, MediaType.APPLICATION_XML)).invoke(); response.close();    }/** * 根据id查询用户 */ private static void getUserById() { System.out.println("****根据id查询用户****"); Client client = ClientBuilder.newClient().register(JacksonJsonProvider.class);// 注册json 支持 WebTarget target = client.target(serverUri + "/users/006"); Response response = target.request().get(); User user = response.readEntity(User.class); System.out.println(user.getUserId() + user.getUserName()  +  user.getAge()); response.close();    }/** * 查询所有用户 */ private static void getAllUsers() { System.out.println("****查询所有getAllUsers****");  Client client = ClientBuilder.newClient(); WebTarget target = client.target(serverUri + "/users"); Response response = target.request().get();  String value = response.readEntity(String.class);      System.out.println(value);         response.close();  //关闭连接 } }

四、运行

启动服务端项目，运行客户端程序UserClient，控制台输出如下

****增加用户addUser********查询所有getAllUsers****[{"userId":"006","userName":"Susan","age":"21"}]****修改用户updateUser********根据id查询用户****006Susan33****查询所有getAllUsers****[{"userId":"006","userName":"Susan","age":"33"}]****删除用户********查询所有getAllUsers****[]

五、总结

1.客户端如果需要进行JSON转换，需要进行JSON注册

 Client client = ClientBuilder.newClient().register(JacksonJsonProvider.class);

2.WebTarget 指明了要请求的资源的地址

3.target.request(). 后面跟的是请求的方法:POST，GET，PUT或DELETE