（七十六）java版spring cloud+spring bo

电子商务平台源码请加企鹅求求：三伍三六贰四柒二伍九。Feign 是简化Java HTTP客户端开发的工具。它使用注解的方式将HTTP的URL封装成接口，每个URL对应一个接口，大大简化了HTTP客户端的开发。

1.添加依赖

<dependency>
<groupId>io.github.openfeign</groupId>
<artifactId>feign-core</artifactId>
</dependency>
<dependency>
<groupId>io.github.openfeign</groupId>
<artifactId>feign-jackson</artifactId>
</dependency>
<dependency>
   <groupId>io.github.openfeign</groupId>
   <artifactId>feign-httpclient</artifactId>
</dependency>
<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
</dependency>

定义API

import feign.Headers;
import feign.Param;
import feign.RequestLine;

import java.util.List;

/**
* Create by zdran@gmail.com on 2018/3/20
*
*/
//Headers 注解：配置请求头信息
@Headers({"Accept: application/json", "Content-Type: application/json"})
public interface UserApi {
/**
* RequestLine 注解：请求的方法与
* GET 请求方法，遵循RESTful风格
* @return
*/
@RequestLine("GET /user/all")
List<User> getAllUser();

/**
* restful方式传参
* @param name
* @return
*/
@RequestLine("GET /user/{name}")
User getByName(@Param("name") St

/**
* url方式传参数
* @param id
* @return
*/
@RequestLine("GET /user/id?id={i
User getById(@Param("id") String

/**
* post 传参，传复杂类型
* @param user
*/
@RequestLine("POST /user/add")
void addUser(User user);
}

定义实现API的controller

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;

import javax.validation.Valid;
import java.util.ArrayList;
import java.util.List;

/**
* Create by zdran@gmail.com on 2018/3/20
 *
 */
@RestController
@RequestMapping(value = "/user", produces = "application/json")
public class UserController {

   @GetMapping(value = "/all")
   List<User> getAll(){
       List<User> users = new ArrayList<>();
       User user = new User();
       user.setName("获取所有用户");
       users.add(user);
       return users;
   }
   @GetMapping(value = "/{name}")
   User getByName(@PathVariable String name){
       User user = new User();
       user.setName("获取用户："+name);
       return user;
   }
   @GetMapping(value = "/id")
   User getById(String id){
       User user = new User();
       user.setName("获取用户："+id);
       return user;
   }
   @PostMapping(value = "/add")
   void addUser(@RequestBody User user){

   }

使用

import feign.Feign;
import feign.httpclient.ApacheHttpClient;
import feign.jackson.JacksonDecoder;
import feign.jackson.JacksonEncoder;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;

/**
 * Create by zdran@gmail.com on 2018/3/20
 *
 */
@Controller
public class ClientController {
    private static final String apiBaseUrl = "http://localhost:8080/feign";
    UserApi userApi = Feign.builder()
           .client(new ApacheHttpClient())
            .encoder(new JacksonEncoder())
            .decoder(new JacksonDecoder())
            .target(UserApi.class, apiBaseUrl);

    @GetMapping(value = "/client/user/{name}")
    public User getUserInfo(@PathVariable String name){
        return userApi.getByName(name);
    }

}