Springboot2.x使用feign优雅调用跨项目接口

1.首先实现server项目，提供数据接口

pom.xml

    4.0.0
    
        org.springframework.boot
        spring-boot-starter-parent
        2.3.1.RELEASE
         
    
    com.frank
    feign-server
    0.0.1-SNAPSHOT
    feign-server
    Demo project for Spring Boot

    
        1.8
    

    
        
            org.springframework.boot
            spring-boot-starter-web
        
    

    
        
            
                org.springframework.boot
                spring-boot-maven-plugin
            
        
    

application.properties

server.port=8081
spring.application.name=user-service
server.servlet.context-path=/api

user

package com.frank.feignserver;

/**
 * @author 小石潭记
 * @date 2020/6/22 21:42
 * @Description: ${todo}
 */
public class User {
    private int id;
    private String name;
    private int age;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public User(int id, String name, int age) {
        this.id = id;
        this.name = name;
        this.age = age;
    }

    public User() {
    }
}

ServerController

package com.frank.feignserver;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.HashMap;
import java.util.Map;

/**
 * @author 小石潭记
 * @date 2020/6/22 21:40
 * @Description: ${todo}
 */
@RestController()
public class ServerController {

    @GetMapping("/getSuccessInfo")
    public Map getSuccessInfo(){
        Map map = new HashMap<>();
        map.put("code", 200);
        map.put("msg", "success");
        map.put("data", new User(1,"小石潭记",26));
        return map;
    }

    @GetMapping("/getFailInfo")
    public Map getFailInfo(){
        Map map = new HashMap<>();
        map.put("code", 404);
        map.put("msg", "fail");
        map.put("data", null);
        return map;
    }
}

FeignServerApplication

package com.frank.feignserver;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class FeignServerApplication {

    public static void main(String[] args) {
        SpringApplication.run(FeignServerApplication.class, args);
    }

}

启动测试：(这里只是简单返回固定的数据用于测试而已)

http://localhost:8081/api/getSuccessInfo

http://localhost:8081/api/getFailInfo

服务端完成成功。

*********feign客户端*********

pom.xml

    4.0.0
    
        org.springframework.boot
        spring-boot-starter-parent
        2.3.1.RELEASE
         
    
    com.frank
    feign-client
    0.0.1-SNAPSHOT
    feign-client
    Demo project for Spring Boot

    
        1.8
    

    
        
            org.springframework.boot
            spring-boot-starter-web
        
        
        
            org.springframework.cloud
            spring-cloud-starter-openfeign
            2.0.2.RELEASE
        
        
        
            org.springframework.cloud
            spring-cloud-starter-netflix-hystrix
            2.0.2.RELEASE
        
        
            org.springframework.cloud
            spring-cloud-netflix-hystrix-dashboard
            2.0.0.RELEASE
        

    

    
        
            
                org.springframework.boot
                spring-boot-maven-plugin
            
        
    

这里使用的是Spring Cloud Starter OpenFeign和springboot1.x不一致，这里需要注意下。

application.properties

server.port=8082
spring.application.name=feign-client
# 开启熔断
feign.hystrix.enabled=true

UserFeignClient

package com.frank.feignclient;

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;

/**
 * @author 小石潭记
 * @date 2020/6/22 21:48
 * @Description: ${todo}
 */
@FeignClient(
        //服务名
        name = "user-service",
        //服务地址
        url = "http://localhost:8081/api",
        fallback = UserHihystric.class
)
public interface UserFeignClient {

    //对应的服务里的接口地址，及请求方式
    @RequestMapping(value = "/getSuccessInfo", method = RequestMethod.GET)
    @ResponseBody
    String getSuccessInfo();

    @RequestMapping(value = "/getFailInfo", method = RequestMethod.GET)
    @ResponseBody
    String getFailInfo();

}

UserHihystric（服务异常时执行，熔断）

package com.frank.feignclient;

import org.springframework.stereotype.Component;

/**
 * @author 小石潭记
 * @date 2020/6/23 20:31
 * @Description: ${todo}
 */
@Component
public class UserHihystric implements UserFeignClient {
    @Override
    public String getSuccessInfo(){
        return "getSuccessInfo serve is bad.";
    }

    @Override
    public String getFailInfo() {
        return "getFailInfo serve is bad.";
    }

}

UserController

package com.frank.feignclient;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * @author 小石潭记
 * @date 2020/6/20 21:38
 * @Description: ${todo}
 */
@RestController
@RequestMapping("/user")
public class UserController {

    @Autowired
    private UserFeignClient userFeignClient;

    @GetMapping("/getSuccessInfo")
    public Object getSuccessInfo(){
        return userFeignClient.getSuccessInfo();
    }

    @GetMapping("/getFailInfo")
    public Object getFailInfo(){
        return userFeignClient.getFailInfo();
    }
}

MyAdvice（这里暂时可以忽略）

package com.frank.feignclient;

import org.springframework.core.MethodParameter;
import org.springframework.http.MediaType;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.server.ServerHttpRequest;
import org.springframework.http.server.ServerHttpResponse;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.servlet.mvc.method.annotation.ResponseBodyAdvice;

/**
 * @author 小石潭记
 * @date 2020/6/22 21:07
 * @Description: ${todo}
 */
@ControllerAdvice
public class MyAdvice implements ResponseBodyAdvice