4–通过jersey-client客户端调用Jersey的Web服务模拟CURD
最后更新于：2022-04-01 20:01:29
## 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 userMap = new HashMap();
~~~
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 getAllUsers(){
List users = new ArrayList();
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
';