Spring Cloud OpenFeign(负载均衡器）

1 OpenFeign简介

OpenFeign是一种声明式、模板化的HTTP客户端。在Spring Cloud中使用OpenFeign，可以做到使用HTTP请求访问远程服务，就像调用本地方法一样的，开发者完全感知不到这是在调用远程方法，更感知不到在访问HTTP请求。

项目结构

1在pom.xml中添加相关依赖

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

        
            org.springframework.cloud
            spring-cloud-starter-netflix-eureka-client
        
        
        
            org.springframework.cloud
            spring-cloud-starter-openfeign
        

2在application.yml进行配置
主要是配置了端口和注册中心地址。

server:
  port: 8085
spring:
  application:
    name: springcloud-openfeign
eureka:
  client:
    register-with-eureka: true
    fetch-registry: true
    service-url:
      defaultZone: http://localhost:8081/eureka/

3编写openfeign调用接口

package com.example.springcloudribbon.service;


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;


@FeignClient(name = "serviceA")
@Component
public interface MyInfo {

    @RequestMapping(value = "/a", method = RequestMethod.GET)
    String getUser();

}

4编写controller

package com.example.springcloudribbon.controller;

import com.example.springcloudribbon.service.MyInfo;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;


import javax.annotation.Resource;

@RestController
public class TestController {


    @Resource
    MyInfo myInfo;

    @GetMapping("/test")
    public String getTest() {

        System.out.println("test-openfeign");
        String result=myInfo.getUser();
        System.out.println(result);
        return result;
    }

    @GetMapping("/test1")
    public String getTest1() {

        return "test1";
    }
}

5 启动项目

访问 url http://localhost:8085/test