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

古城微笑少年丶 2022-04-21 16:04 159阅读 0赞

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