详解spring cloud使用Hystrix实现单个方法的fallback

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

package com.chhliu.springboot.restful.controller;  
import org.springframework.beans.factory.annotation.Autowired; 
import org.springframework.web.bind.annotation.GetMapping; 
import org.springframework.web.bind.annotation.PathVariable; 
import org.springframework.web.bind.annotation.RestController;  
import com.chhliu.springboot.restful.feignclient.UserFeignClient; 
import com.chhliu.springboot.restful.vo.User; 
import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;  
@RestController 
public class RestTemplateControllerHystrixCommand { 
   
  @Autowired 
  private UserFeignClient client; // 使用Feign来消费Restful服务 
   
  @GetMapping("/get/{id}") 
  @HystrixCommand(fallbackMethod="findByIdFallback")// 使用HystrixCommand注解，在fallbackMethod属性中指定fallback的方法 
  public User findById(@PathVariable Long id) { 
    return client.findById(id); 
  } 
   
    // 覆写fallbackMethod中指定的方法，注意，此方法的返回值，参数必须与原方法一致 
  public User findByIdFallback(Long id){ 
    User u = new User(); 
    u.setName("zhangsan"); 
    u.setUsername("chhliu"); 
    u.setId(9L); 
    return u; 
  } 
} 

@EnableCircuitBreaker 

server.port:7904 
# spring boot服务注册到Eureka Server上的应用名称 
spring.application.name=springboot-rest-template-feign-hystrix 
eureka.instance.prefer-ip-address=true 
# Eureka Server注册服务的地址 
eureka.client.service-url.defaultZone=http://chhliu:chhliu123456@localhost:8764/eureka 
springboot-h2.ribbon.NFLoadBalancerRuleClassName=com.netflix.loadbalancer.RetryRule 
hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds: 1 #为了测试Hystrix的fallback效果，此处将超时时间设置成1毫秒