1.pom.xml

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
        </dependency>

2.启用

@SpringBootApplication
@EnableEurekaClient
@EnableHystrix
public class MemberServiceApplication {

    @Bean
    @LoadBalanced  // 负载均衡注解，通过restTemplate 发送的请求默认带有负载均衡的特性(轮询)
    public RestTemplate restTemplatem(){
        return new RestTemplate();
    }

    /*
        针对全局进行配置, 优先级最高
     */
    @Bean
    public IRule ribbonRule(){
        return new RoundRobinRule();
    }

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

}

3. 调用

package com.itlaoqi.springcloud.memberservice.controller;

import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

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

@RestController
public class MemberController {

    @Autowired
    private RestTemplate restTemplate;
    /**
     *  RestTemplate 负载均衡 格式要求
     *  http://微服务id/webapi地址
     */
    @RequestMapping("/sendMess")
    @HystrixCommand(fallbackMethod = "sendMessFail")
    public Map<String,Object> sendMess(@RequestParam("phone")String phone){
        Map<String,Object> paramMap = new HashMap<>();
        paramMap.put("phone",phone);
        return restTemplate.getForObject("http://book-service/sendMess", Map.class,paramMap);
    }

    public Map<String,Object> sendMessFail(@RequestParam("phone")String phone){
        Map<String,Object> paramMap = new HashMap<>();
        paramMap.put("code",-1);
        paramMap.put("message","发送失败");
        return paramMap;
    }

}