Hystrix再学习

 为什么会被卡死？

                   tomcat的默认的工作线程数被打满了，没有多余的线程来分解压力和处理。

 POM文件：

        <!--新增hystrix-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>

 

服务降级：

package com.atguigu.springcloud.service;

import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
import com.netflix.hystrix.contrib.javanica.annotation.HystrixProperty;
import org.springframework.stereotype.Service;

import java.util.concurrent.TimeUnit;

@Service
public class PaymentService {

    //成功
    public String paymentInfo_OK(Integer id){
        return "线程池："+Thread.currentThread().getName()+"   paymentInfo_OK,id：  "+id+"	"+"哈哈哈"  ;
    }

    //失败
    @HystrixCommand(fallbackMethod = "paymentInfo_TimeOutHandler",commandProperties = {
            @HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds",value = "3000")  //3秒钟以内就是正常的业务逻辑
    })
    public String paymentInfo_TimeOut(Integer id){
       // int timeNumber = 5;
        int age = 10/0;
       // try { TimeUnit.SECONDS.sleep(timeNumber); }catch (Exception e) {e.printStackTrace();}
        //return "线程池："+Thread.currentThread().getName()+"   paymentInfo_TimeOut,id：  "+id+"	"+"呜呜呜"+" 耗时(秒)"+timeNumber;
        return "线程池："+Thread.currentThread().getName()+"   paymentInfo_TimeOut,id：  "+id+"	"+"呜呜呜"+" 耗时(秒)";
    }

    //兜底方法
    public String paymentInfo_TimeOutHandler(Integer id){
        return "线程池："+Thread.currentThread().getName()+"   系统繁忙或者运行时异常, 请稍候再试  ,id：  "+id+"	"+"哭了哇呜";
    }

}

Hystrix的服务降级可以在客户端也可以在服务端，但是一般放在客户端，即消费者。但是，我们自己配置过的热部署方式对java代码的改动明显，但对@HystrixCommand内属性的修改建议重 启微服务

做不同的服务降级的yml:

代码膨胀： 每个业务方法对应一个兜底的方法，代码膨胀，且每个兜底方法和业务方法混在一起。

 

  

即有配置@HystrixCommand的就用特指的，否则用@DefaultPropertie通用的

package com.atguigu.springcloud.controller;

import com.atguigu.springcloud.service.PaymentHystrixService;
import com.netflix.hystrix.contrib.javanica.annotation.DefaultProperties;
import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
import com.netflix.hystrix.contrib.javanica.annotation.HystrixProperty;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;

@RestController
@Slf4j
@DefaultProperties(defaultFallback = "payment_Global_FallbackMethod")  //全局的
public class OrderHystrixController {

    @Resource
    private PaymentHystrixService paymentHystrixService;

    @GetMapping("/consumer/payment/hystrix/ok/{id}")
    public String paymentInfo_OK(@PathVariable("id") Integer id){
        String result = paymentHystrixService.paymentInfo_OK(id);
        return result;
    }

//    @GetMapping("/consumer/payment/hystrix/timeout/{id}")
//    public String paymentInfo_TimeOut(@PathVariable("id") Integer id){
//        String result = paymentHystrixService.paymentInfo_TimeOut(id);
//        return result;
//    }

    @GetMapping("/consumer/payment/hystrix/timeout/{id}")
//    @HystrixCommand(fallbackMethod = "paymentTimeOutFallbackMethod",commandProperties = {
//            @HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds",value = "1500")  //1.5秒钟以内就是正常的业务逻辑
//    })
    @HystrixCommand
    public String paymentInfo_TimeOut(@PathVariable("id") Integer id){
        int age = 10/0;
        String result = paymentHystrixService.paymentInfo_TimeOut(id);
        return result;
    }

    //兜底方法
    public String paymentTimeOutFallbackMethod(@PathVariable("id") Integer id){
        return "我是消费者80，对付支付系统繁忙请10秒钟后再试或者自己运行出错请检查自己,(┬＿┬)";
    }

    //下面是全局fallback方法
    public String payment_Global_FallbackMethod(){
        return "Global异常处理信息，请稍后再试,(┬＿┬)";
    }
}


 

代码混乱

代码混乱的解决： 

cotroller:

package com.atguigu.springcloud.service;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
/**
 * @author wsk
 * @date 2020/3/14 10:21
 */
@Component
@FeignClient(value = "CLOUD-PROVIDER-HYSTRIX-PAYMENT" ,fallback = PaymentFallbackService.class)
public interface PaymentHystrixService {

    @GetMapping("/payment/hystrix/ok/{id}")
    public String paymentInfo_OK(@PathVariable("id") Integer id);

    @GetMapping("/payment/hystrix/timeout/{id}")
    public String paymentInfo_TimeOut(@PathVariable("id") Integer id);
}

实现接口：

package com.atguigu.springcloud.service;

import org.springframework.stereotype.Component;

@Component
public class PaymentFallbackService implements PaymentHystrixService {
    @Override
    public String paymentInfo_OK(Integer id) {
        return "-----PaymentFallbackService fall back-paymentInfo_OK , (┬＿┬)";
    }

    @Override
    public String paymentInfo_TimeOut(Integer id) {
        return "-----PaymentFallbackService fall back-paymentInfo_TimeOut , (┬＿┬)";
    }
}

yml:

server:
  port: 80

eureka:
  client:
    fetch-registry: false
    service-url:
      defaultZone: http://eureka7001.com:7001/eureka/

feign:
  hystrix:
    enabled: true

主启动类：

package com.atguigu.springcloud;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.hystrix.EnableHystrix;
import org.springframework.cloud.openfeign.EnableFeignClients;
/**
 * @author wsk
 * @date 2020/3/14 10:09
 */
@SpringBootApplication
@EnableFeignClients
@EnableHystrix
public class OrderHystrixMain80 {
    public static void main(String[] args) {
        SpringApplication.run(OrderHystrixMain80.class,args);
    }
}

二：服务熔断

 cotroller:

//服务熔断
@HystrixCommand(fallbackMethod = "paymentCircuitBreaker_fallback",commandProperties = {
        @HystrixProperty(name = "circuitBreaker.enabled",value = "true"),  //是否开启断路器
        @HystrixProperty(name = "circuitBreaker.requestVolumeThreshold",value = "10"),   //请求次数
        @HystrixProperty(name = "circuitBreaker.sleepWindowInMilliseconds",value = "10000"),  //时间范围
        @HystrixProperty(name = "circuitBreaker.errorThresholdPercentage",value = "60"), //失败率达到多少后跳闸
})
public String paymentCircuitBreaker(@PathVariable("id") Integer id){
    if (id < 0){
        throw new RuntimeException("*****id 不能负数");
    }
    String serialNumber = IdUtil.simpleUUID();

    return Thread.currentThread().getName()+"	"+"调用成功,流水号："+serialNumber;
}

public String paymentCircuitBreaker_fallback(@PathVariable("id") Integer id){
    return "id 不能负数，请稍候再试,(┬＿┬)/~~     id: " +id;
}
 

断路器在什么情况下开始起作用?

 断路器开启或者关闭的条件:

 断路器打开之后:

open-------  half open ---- close               

结论：

  1:先熔断，在服务降级

   2 多次错误然后慢慢正确，发现刚开始不满足条件，就算是正确的访问地址也不能进行访问，需要慢慢的恢复链路,

服务监控hystrixDashboard：

actuator监控信 息完善

 注意：新版本Hystrix需要在主启动类MainAppHystrix8001中指定监控路径

package com.atguigu.springcloud;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.hystrix.dashboard.EnableHystrixDashboard;

@SpringBootApplication
@EnableHystrixDashboard
public class HystrixDashboardMain9001 {
    public static void main(String[] args) {
        SpringApplication.run(HystrixDashboardMain9001.class,args);
    }
 

//springcloud升级后要加入否则会被报错

@Bean
public ServletRegistrationBean getServlet(){
    HystrixMetricsStreamServlet streamServlet = new HystrixMetricsStreamServlet();
    ServletRegistrationBean registrationBean = new ServletRegistrationBean(streamServlet);
    registrationBean.setLoadOnStartup(1);
    registrationBean.addUrlMappings("/hystrix.stream");
    registrationBean.setName("HystrixMetricsStreamServlet");
    return registrationBean;
}
 
}