代码结构如下：

pom 文件中添加  hystrix

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

UserApplication 添加  @EnableHystrix 代码如下

package com.study.user;


import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.netflix.feign.EnableFeignClients;
import org.springframework.cloud.netflix.hystrix.EnableHystrix;

@EnableEurekaClient
@SpringBootApplication
@EnableHystrix
public class UserApplication {

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

}

UserService 代码如下

package com.study.user.service;


import java.util.List;
import java.util.Map;


public interface UserService {

    List<Map<String, Object>> getMenu();


}

UserServiceImpl 代码如下

package com.study.user.service.impl;

import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
import com.study.user.service.UserService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;
import org.springframework.core.ParameterizedTypeReference;
import org.springframework.http.HttpMethod;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

@Service
public class UserServiceImpl implements UserService {

    private static final Logger logger = LoggerFactory.getLogger(UserServiceImpl.class);

    @Autowired
    private LoadBalancerClient loadBalancerClient;//ribbon负载均衡器s

    public List<Map<String, Object>> getMenuError() {
        List<Map<String, Object>> list = new ArrayList<>();
        Map<String, Object> map = new HashMap<>();
        map.put("menu", "菜单1111122222");
        list.add(map);
        return list;
    }

    @HystrixCommand(fallbackMethod = "getMenuError")
    @Override
    public List<Map<String, Object>> getMenu() {
        //选择调用的服务的名称
        //ServiceInstance 封装了服务的基本信息，如 IP，端口
        ServiceInstance si = this.loadBalancerClient.choose("menu");
        //拼接访问服务的URL
        StringBuffer sb = new StringBuffer();
        //http://localhost:9090/user
        sb.append("http://").append(si.getHost()).append(":").append(si.getPort()).append("/menu/getMenu");
        //springMVC RestTemplate
        RestTemplate rt = new RestTemplate();
        ParameterizedTypeReference<List<Map<String, Object>>> type = new ParameterizedTypeReference<List<Map<String, Object>>>() {
        };
        //ResponseEntity:封装了返回值信息
        ResponseEntity<List<Map<String, Object>>> response = rt.exchange(sb.toString(), HttpMethod.GET, null, type);
        List<Map<String, Object>> list = response.getBody();
        return list;
    }
}

代码结束

访问  http://127.0.0.1:8763/user/getMenu

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