spring cloud Uses Hystrix to implement fallback for a single method

  • 2021-01-03 20:54:46
  • OfStack

This article introduces spring cloud- fallback that uses Hystrix to implement a single method. It is shared as follows:

1. Add Hystrix dependencies


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

2. Write Controller


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; //  use Feign To consume Restful service  
   
  @GetMapping("/get/{id}") 
  @HystrixCommand(fallbackMethod="findByIdFallback")//  use HystrixCommand Annotations, fallbackMethod Property to specify fallback The method of  
  public User findById(@PathVariable Long id) { 
    return client.findById(id); 
  } 
   
    //  overwrite fallbackMethod Note that the return value of this method, parameters must be the same as the original method 1 to  
  public User findByIdFallback(Long id){ 
    User u = new User(); 
    u.setName("zhangsan"); 
    u.setUsername("chhliu"); 
    u.setId(9L); 
    return u; 
  } 
} 

3. Add Hystrix support to the startup class


@EnableCircuitBreaker 

4. Add configuration files


server.port:7904 
# spring boot Service registration to Eureka Server The name of the application  
spring.application.name=springboot-rest-template-feign-hystrix 
eureka.instance.prefer-ip-address=true 
# Eureka Server Register the address of the service  
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 # In order to test Hystrix the fallback Effect, where the timeout is set to 1 ms  

5. Test

In the browser input: http: / / localhost: 7904 / get / 2

The test results are as follows:

[

{"id":9,"username":"chhliu","name":"zhangsan","age":null,"balance":null}

]

As you can see from the above test results, the connection timeout went directly to the fallback method.


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