搭建springcloud的demo之Hystrix服务降级 (八)

布满荆棘的人生 2022-03-02 11:44 197阅读 0赞

## 服务降级 ##

整体资源快不够了,忍痛将某些服务先关掉,待渡过难关.再开启回来;

## 服务降级处理是在客户端实现完成的,与服务端没有关系 ##

## 修改microservicecloud-api工程,根据已经有的DeptClientService接口新建一个实现了FallbackFactory接口的类DeptClientServiceFallbackFactory ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3l1YW50aW5nXw_size_16_color_FFFFFF_t_70]

package com.yt.springcloud.service;
    
    import java.util.List;
    
    import org.springframework.stereotype.Component;
    
    import com.yt.springcloud.entity.Dept;
    
    import feign.hystrix.FallbackFactory;
    
    @Component // 不要忘记添加，不要忘记添加
    public class DeptClientServiceFallbackFactory implements FallbackFactory<DeptClientService>
    {
    	@Override
    	public DeptClientService create(Throwable throwable)
    	{
    		return new DeptClientService() {
    			@Override
    			public Dept get(long id)
    			{
    				return new Dept().setDeptno(id).setDname("该ID：" + id + "没有没有对应的信息,Consumer客户端提供的降级信息,此刻服务Provider已经关闭")
    						.setDb_source("no this database in MySQL");
    			}
    
    			@Override
    			public List<Dept> list()
    			{
    				return null;
    			}
    
    			@Override
    			public boolean add(Dept dept)
    			{
    				return false;
    			}
    		};
    	}
    }

## 修改microservicecloud-api工程,DeptClientService接口在注解@FeignClient ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3l1YW50aW5nXw_size_16_color_FFFFFF_t_70 1]

package com.yt.springcloud.service;
    
    import java.util.List;
    
    import org.springframework.cloud.netflix.feign.FeignClient;
    import org.springframework.web.bind.annotation.PathVariable;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestMethod;
    
    import com.yt.springcloud.entity.Dept;
    
    /**
     * 
     * @Description: 修改microservicecloud-api工程，根据已经有的DeptClientService接口
     * 一个实现了FallbackFactory接口的类DeptClientServiceFallbackFactory
     * @author zzyy
     * @date 2018年4月21日
     */
    //@FeignClient(value = "MICROSERVICECLOUD-DEPT")//针对于更细粒化的控制,针对哪一个微服务进行面向接口的feign的
    @FeignClient(value = "MICROSERVICECLOUD-DEPT",fallbackFactory=DeptClientServiceFallbackFactory.class)
    //把当前接口的所有方法,都交给fallback去处理,是这个类DeptClientServiceFallbackFactory.class实现了fallbackfactory
    public interface DeptClientService
    {
    	@RequestMapping(value = "/dept/get/{id}", method = RequestMethod.GET)
    	public Dept get(@PathVariable("id") long id);
    
    	
    	@RequestMapping(value = "/dept/list", method = RequestMethod.GET)
    	public List<Dept> list();
    
    	@RequestMapping(value = "/dept/add", method = RequestMethod.POST)
    	public boolean add(Dept dept);
    }

## microservicecloud-api工程 重新打包maven-clean–>maven install ##

## microservicecloud-consumer-dept-feign工程修改yml ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3l1YW50aW5nXw_size_16_color_FFFFFF_t_70 2]

server :
       port: 80
       
       
    feign: 
      hystrix: 
          enabled: true #开启hystrix
          
       
       
    eureka:
       client:
         register-with-eureka: false #自己不能注册
         service-url:
           defaultZone: http://eureka7001.com:7001/eureka/,http://eureka7002.com:7002/eureka/,http://eureka7003.com:7003/eureka/
           #eureka集群

## 测试 ##

1.  3个rureka启动
2.  微服务microservicecloud-provider-dept-8001启动
3.  microservicecloud-consumer-dept-feign启动
4.  正常访问测试:[http://localhost/consumer/dept/get/1][http_localhost_consumer_dept_get_1]  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3l1YW50aW5nXw_size_16_color_FFFFFF_t_70 3]
5.  故意关闭微服务microservicecloud-provider-dept-8001
6.  客户端自己调用提示  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3l1YW50aW5nXw_size_16_color_FFFFFF_t_70 4]  
    此时服务端provider已经down了,但是我们做了服务降级处理,让客户端不可用时也会获得提示信息而不会挂起耗死服务器;

## 总结 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3l1YW50aW5nXw_size_16_color_FFFFFF_t_70 5]  
翻译于尚硅谷周阳老师:[https://www.bilibili.com/video/av22613028?from=search&seid=11377756339718254280][https_www.bilibili.com_video_av22613028_from_search_seid_11377756339718254280]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3l1YW50aW5nXw_size_16_color_FFFFFF_t_70]: /images/20220302/de144a4093f6419ca4264c35dfcdd53c.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3l1YW50aW5nXw_size_16_color_FFFFFF_t_70 1]: /images/20220302/e8602217091b448394fdec0686514210.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3l1YW50aW5nXw_size_16_color_FFFFFF_t_70 2]: /images/20220302/d1122e3e2b514a56988e99ad924a478c.png
[http_localhost_consumer_dept_get_1]: http://localhost/consumer/dept/get/1
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3l1YW50aW5nXw_size_16_color_FFFFFF_t_70 3]: /images/20220302/d38cac0da5f74c0980d499be13d5419b.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3l1YW50aW5nXw_size_16_color_FFFFFF_t_70 4]: /images/20220302/46e4204da65c4704965c05aa56046052.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3l1YW50aW5nXw_size_16_color_FFFFFF_t_70 5]: /images/20220302/05c0eca4b1634f5c9e397d6f57d6e562.png
[https_www.bilibili.com_video_av22613028_from_search_seid_11377756339718254280]: https://www.bilibili.com/video/av22613028?from=search&seid=11377756339718254280