用Jersey構建RESTful服務4--通過jersey-client客戶端調用Jersey的Web服務模擬CURD

一、總體說明

通過jersey-client接口，創建客戶端程序，來調用Jersey實現的RESTful服務，實現增、刪、改、查等操作。

服務端主要是通過內存的方式，來模擬用戶的增加、刪除、修改、查詢等操作。

二、創建服務端

1.在上文項目中，

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

首先創建一個HashMap，用來保存添加的用戶

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

2.創建增、刪、改、查 用戶資源等操作

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/**
     * 增加
     * @param user
     */
    @POST
    @Consumes({MediaType.APPLICATION_XML, MediaType.APPLICATION_JSON})
    public void createStudent(User user)
    {
        userMap.put(user.getUserId(), user );
    }

    /**
     * 刪除
     * @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 );
    }

    /**
     * 根據id查詢
     * @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;
    }

    /**
     * 查詢所有
     * @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、創建客戶端程序

1.創建包“com.waylau.rest.client”，在包下建一個UserClient.java，代碼如下：

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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;


/**
 * 用戶客戶端，用來測試資源
 * @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();

    }
    /**
     * 添加用戶
     */
     private static void addUser() {
         System.out.println("****增加用戶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();
    }

    /**
     * 刪除用戶
     */
     private static void delUser() {
         System.out.println("****刪除用戶****");
         Client client = ClientBuilder.newClient();
         WebTarget target = client.target(serverUri + "/users/006");
         Response response = target.request().delete();
         response.close();
    }


    /**
     * 修改用戶
     */
     private static void updateUser() {
         System.out.println("****修改用戶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();
    }
    /**
     * 根據id查詢用戶
     */
     private static void getUserById() {
         System.out.println("****根據id查詢用戶****");
         Client client = ClientBuilder.newClient().register(JacksonJsonProvider.class);// 註冊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();
    }
    /**
     * 查詢所有用戶
     */
     private static void getAllUsers() {
         System.out.println("****查詢所有getAllUsers****");

         Client client = ClientBuilder.newClient();

         WebTarget target = client.target(serverUri + "/users");
         Response response = target.request().get();
 <span style="white-space:pre">     </span> String value = response.readEntity(String.class);
    <span style="white-space:pre">     <span style="white-space:pre"> </span></span> System.out.println(value);
        <span style="white-space:pre">  </span> response.close();  //關閉連接
     }

}

四、運行

啓動服務端項目，運行客戶端程序UserClient，控制檯輸出如下

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****增加用戶addUser****
****查詢所有getAllUsers****
[{"userId":"006","userName":"Susan","age":"21"}]
****修改用戶updateUser****
****根據id查詢用戶****
006Susan33
****查詢所有getAllUsers****
[{"userId":"006","userName":"Susan","age":"33"}]
****刪除用戶****
****查詢所有getAllUsers****
[]

五、總結

1.客戶端如果需要進行JSON轉換，需要進行JSON註冊

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

2.WebTarget 指明瞭要請求的資源的地址

3.target.request(). 後面跟的是請求的方法:POST，GET，PUT或DELETE