springcloud集成Feign，Hystrix

àì夳堔傛蜴生んèń 2021-09-23 12:34 407阅读 0赞

核心功能 Feign + Hystrix 服务熔断和服务降级

服务降级即指 返回默认值  
服务熔断即指 服务不可用或请求服务超时 即调用服务降级

1springcloud消费者（consumer）引入 Feign依赖，会自动引入Hystrix依赖的

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

2新建FeignService类

import org.springframework.cloud.netflix.feign.FeignClient;
    import org.springframework.web.bind.annotation.*;
    
    import com.jorian.sc_eureka_consumer.dao.impl.FeignFallBack;
    
    /**
     * 
     * @author gyn
     *
     */
    //value=“你用到的服务名称”
    //fallback = FeignService实现类 我们这里先创建接口 下一步在创建FeignFallBack
    @FeignClient(value = "provider-user",fallback = FeignFallBack.class)
    
    public interface FeignService {
    	//服务中方法的映射路径
        @RequestMapping(value = "/hello", method = RequestMethod.GET)
        String hello(@RequestParam("name") String name);
    
    }

3FeignService实现类 ，配置服务不可调用时返回值

import org.springframework.stereotype.Component;
    import org.springframework.web.bind.annotation.RequestMapping;
    
    import com.jorian.sc_eureka_consumer.dao.FeignService;
    
    /**
     * 
     * @author gyn
     * 配置服务不可调用时返回值
     */
    @Component
    @RequestMapping("/")//配置路径
    public class FeignFallBack implements FeignService{
        //实现的方法是服务调用的降级方法
        @Override
        public String hello(String name) {
            return "hello error";
        }
    
      
    }

4 application.yml后面加入

feign:
      hystrix:
        enabled: true
        
    hystrix:
      command:
        default:
          execution:
            isolation:
              thread:
                timeoutInMilliseconds: 2000

timeoutInMilliseconds调用生产者的超时时间 默认1秒 不配置抛异常 具体几秒根据自己需要来配置

import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    import org.springframework.web.client.RestTemplate;
    
    import com.jorian.sc_eureka_consumer.dao.FeignService;
    
     
    @RestController
    public class HelloController {
    	@Autowired
    	private RestTemplate resttemplate;
    	@Autowired
        FeignService feignService;
    
    	@RequestMapping("/consumer")
    	public String consumer(String name){
    		System.err.println("---------------   login hello "+name);
    		//返回值类型和我们的业务返回值一致
    		return feignService.hello(name);
    	
    	}
    }

6关闭所有生产者（provider）  
调用 http://localhost:7902/consumer?name=qwer  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzI1OTU4NDk3_size_16_color_FFFFFF_t_70]  
如图所示即配成功

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzI1OTU4NDk3_size_16_color_FFFFFF_t_70]: /images/20210923/56208ad8ab0845dca60a74a9e3056dc2.png