# 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 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 **本章源码**:[https://github.com/waylau/RestDemo/tree/master/jersey-demo4-client-curd](https://github.com/waylau/RestDemo/tree/master/jersey-demo4-client-curd)