springCloud Finchley 微服务架构从入门到精通【八】断路器 Hystrix(feign)

待我称王封你为后i 2023-10-17 21:19 49阅读 0赞

\#\#一、前言\#\#  
上节写了ribbon 整合hystrix的实例，本节准备实现feign，由于比较简单，只写关键代码，具体看github源码

\#\#二、代码实现\#\#

**创建fallback包存放feign的fallback处理类，包结构如下：**

![这里写图片描述][70]  
**UserFeignApi为入口调用类**

package com.mayi.springcloud.api;
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    import com.mayi.springcloud.client.UserFeignClient;
    
    @RestController
    public class UserFeignApi {
        
    	
    	@Autowired
    	private UserFeignClient userFeignClient;
    	
    	@GetMapping("/listUsersByFeign")
    	public String ListUsers(){
        
    		String users = this.userFeignClient.listUsers();
    		return users;
    	}
    	
    }

**UserFeignClient为实现feign的接口**

package com.mayi.springcloud.client;
    
    import org.springframework.cloud.openfeign.FeignClient;
    import org.springframework.web.bind.annotation.GetMapping;
    
    import com.mayi.springcloud.fallback.UserFallback;
    
    @FeignClient(name="service-user", fallback=UserFallback.class)
    public interface UserFeignClient {
        
    	
    	@GetMapping("/listUsers")
    	public String listUsers();
    	
    }

**UserFallback为节点故障处理类**

package com.mayi.springcloud.fallback;
    
    import org.springframework.stereotype.Component;
    
    import com.mayi.springcloud.client.UserFeignClient;
    
    @Component
    public class UserFallback implements UserFeignClient{
        
    
    	@Override
    	public String listUsers() {
        
    		// TODO Auto-generated method stub
    		return "服务调用失败";
    	}
    
    }

**配置中心的service-feign-hystrix-dev.yml**

server:
      port: 1001
    feign: 
      hystrix: 
        enabled: true

\#\#三、测试\#\#  
依次启动下图服务

![这里写图片描述][70 1]

访问http://localhost:1001/listUsersByFeign，交替出现

![这里写图片描述][70 2]

手动停止其中一个service-user服务，当负载均衡至该节点，会转到自定义的fallback类

![这里写图片描述][70 3]

若干秒后，该故障节点会被剔除，之后不会被其他调用者访问到。

源码地址：https://github.com/tianyana/springcloud/tree/master/bussnessservice-user-client-feign-hystrix

[70]: https://img-blog.csdn.net/20180509122630225?watermark/2/text/aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3djYmxvZw==/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70
[70 1]: https://img-blog.csdn.net/20180509122646839?watermark/2/text/aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3djYmxvZw==/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70
[70 2]: https://img-blog.csdn.net/20180509122658618?watermark/2/text/aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3djYmxvZw==/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70
[70 3]: https://img-blog.csdn.net/20180509122711571?watermark/2/text/aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3djYmxvZw==/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70