SpringCloud之Hystrix的詳細(xì)使用

更新時間：2022年01月24日 17:17:20 作者：sky~

熔斷機制是應(yīng)對雪崩效應(yīng)的一種微服務(wù)鏈路保護(hù)機制,當(dāng)扇出鏈路的某個微服務(wù)出錯不可用或者響應(yīng)時間太長,會進(jìn)行服務(wù)的降級,進(jìn)而熔斷該節(jié)點微服務(wù)的調(diào)用,快速返回錯誤的相應(yīng)信息，本文重點給大家介紹SpringCloud Hystrix使用，感興趣的朋友一起看看吧

1.概念

服務(wù)降級：服務(wù)器繁忙，請稍后再試，不讓客戶端等待，并立即返回一個友好的提示（一般發(fā)生在程序異常，超時，服務(wù)熔斷觸發(fā)服務(wù)降級，線程池、信號量打滿也會導(dǎo)致服務(wù)降級）
服務(wù)熔斷：達(dá)到最大服務(wù)訪問后，直接拒絕訪問，然后調(diào)用服務(wù)降級的方法并返回友好提示（如保險絲一樣）
服務(wù)限流：秒殺等高并發(fā)操作，嚴(yán)禁一窩蜂的過來擁擠，排隊進(jìn)入，一秒鐘N個，有序進(jìn)行

一.服務(wù)降級

2.不使用Hystrix的項目

大致的Service和Controller層如下

***************Controller*****************
package com.sky.springcloud.controller;

import com.sky.springcloud.service.PaymentService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
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
public class PaymentController {
    @Resource
    private PaymentService paymentService;
    @Value("${server.port}")
    private String serverport;
    @GetMapping("/payment/hystrix/ok/{id}")
    public String paymentInfo_Ok(@PathVariable("id") Integer id){
        String result = paymentService.paymentInfo_ok(id);
        log.info("*****"+ result);
        return result;
    }
    @GetMapping("/payment/hystrix/timeout/{id}")
    public String paymentInfo_TimeOut(@PathVariable("id") Integer id){
        String result = paymentService.payment_Info_TimeOut(id);
}
*******************Service******************** 
package com.sky.springcloud.service;
import org.springframework.stereotype.Service;
import java.util.concurrent.TimeUnit;
@Service
public class PaymentServiceImpl implements PaymentService{
    @Override
    public String paymentInfo_ok(Integer id) {
        return "線程池：" + Thread.currentThread().getName() + "paymentInfo_Ok. id:" + id + "\t" + "~~~~~";
    public String payment_Info_TimeOut(Integer id) {
       try {
            TimeUnit.SECONDS.sleep(5);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return "線程池：" + Thread.currentThread().getName() + "paymentInfo_TimeOut. id:" + id + "\t" + "~~~~~";

在這種情況時,當(dāng)通過瀏覽器訪問 TimeOut這個方法,會三秒后返回結(jié)果,而當(dāng)訪問 OK 這個方法時,會直接返回結(jié)果(但是這是在訪問量很少的時候,一旦訪問量過多,訪問OK時也會出現(xiàn)延遲,這里可以使用Jmeter模擬兩萬個訪問量,如下)

在這里插入圖片描述

使用 Jmeter 模擬后,再去訪問OK,會明顯出現(xiàn)加載的效果

3. 使用Hystrix

在主啟動類添加注解
@EnableHystrix

package com.sky.springcloud;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.netflix.hystrix.EnableHystrix;
@SpringBootApplication
@EnableEurekaClient //啟用Eureka
@EnableHystrix     //啟用Hystrix
public class Payment8001 {
    public static void main(String[] args) {
        SpringApplication.run(Payment8001.class,args);
    }
}

在原有的基礎(chǔ)上,在Service層加上如下注解

 @HystrixCommand(fallbackMethod = "payment_Info_TimeOutHandler",//當(dāng)服務(wù)降級時,調(diào)用payment_Info_TimeOutHandler方法
                  commandProperties = {
            @HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds",
            value = "3000")//設(shè)置時間為3秒,超過三秒就為時間超限

*****************改后的Service*******************
package com.sky.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 PaymentServiceImpl implements PaymentService{
    @Override
    public String paymentInfo_ok(Integer id) {
        return "線程池：" + Thread.currentThread().getName() + "paymentInfo_Ok. id:" + id + "\t" + "~~~~~";
    }

    @HystrixCommand(fallbackMethod = "payment_Info_TimeOutHandler",commandProperties = {
            @HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds",value = "3000")
    })
    public String payment_Info_TimeOut(Integer id) {
      try {
            TimeUnit.SECONDS.sleep(5);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
      // int a = 10 / 0;
        return "線程池：" + Thread.currentThread().getName() + "paymentInfo_TimeOut. id:" + id + "\t" + "~~~~~";
    }
    public String payment_Info_TimeOutHandler(Integer id){
        return "線程超時或異常 " + Thread.currentThread().getName();
    }
}

如上Service所示,如果再次訪問TimeOut需要等待五秒,但是Hystrix設(shè)置的超時時間為三秒,所以當(dāng)三秒后沒有結(jié)果就會服務(wù)降級,從而調(diào)用TimeOutHandler這個指定的方法來執(zhí)行(或者有程序出錯等情況也會服務(wù)降級)

4. 全局的Hystrix配置

@DefaultProperties(defaultFallback = “Gloub_Test”)

package com.sky.springcloud.service;

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 org.springframework.stereotype.Service;
@Service
@DefaultProperties(defaultFallback = "Gloub_Test")
public class PaymentServiceImpl implements PaymentService{
    @Override
    @HystrixCommand
    public String paymentInfo_ok(Integer id) {
        int a = 10 / 0;
        return "線程池：" + Thread.currentThread().getName() + "paymentInfo_Ok. id:" + id + "\t" + "~~~~~";
    }
    @HystrixCommand(fallbackMethod = "payment_Info_TimeOutHandler",commandProperties = {
            @HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds",value = "3000")
    })
    public String payment_Info_TimeOut(Integer id) {
   /*     try {
            TimeUnit.SECONDS.sleep(5);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }*/
        return "線程池：" + Thread.currentThread().getName() + "paymentInfo_TimeOut. id:" + id + "\t" + "~~~~~";
    public String payment_Info_TimeOutHandler(Integer id){
        return "線程超時或異常 " + Thread.currentThread().getName();
    public String Gloub_Test(){
        return "走了全局的";
}

如上Service所示,加了@HystrixCommand的方法里,
如果沒指定fallbackMethod 就會默認(rèn)去找全局的defaultFallback
這里當(dāng)paymentInfo_ok 方法出錯時,會調(diào)用Gloub_Test方法
當(dāng)payment_Info_TimeOut出錯時,會調(diào)用payment_Info_TimeOutHandler方法

二.服務(wù)熔斷

1.熔斷機制概述

熔斷機制是應(yīng)對雪崩效應(yīng)的一種微服務(wù)鏈路保護(hù)機制,當(dāng)扇出鏈路的某個微服務(wù)出錯不可用或者響應(yīng)時間太長,會進(jìn)行服務(wù)的降級,進(jìn)而熔斷該節(jié)點微服務(wù)的調(diào)用,快速返回錯誤的相應(yīng)信息.當(dāng)檢測到該節(jié)點微服務(wù)調(diào)用相應(yīng)正常后,恢復(fù)調(diào)用鏈路.

2.項目中使用

在上面的基礎(chǔ)上,改寫Service和Controller(添加以下代碼)

//是否開啟服務(wù)熔斷(斷路器)
 @HystrixProperty(name = "circuitBreaker.enabled",value = "true"),
 //服務(wù)請求的次數(shù) 
 @HystrixProperty(name = "circuitBreaker.requestVolumeThreshold",value = "10"),
 //時間的窗口期
 @HystrixProperty(name = "circuitBreaker.sleepWindowInMilliseconds", value = "10000"),
 //當(dāng)失敗率達(dá)到多少后發(fā)生熔斷
 @HystrixProperty(name = "circuitBreaker.errorThresholdPercentage",value = "60"), 

******************Service*****************
    @HystrixCommand(fallbackMethod = "paymentCircuitBreaker_fallback",
                    commandProperties = {
                    @HystrixProperty(name = "circuitBreaker.enabled",value = "true"),
                    @HystrixProperty(name = "circuitBreaker.requestVolumeThreshold",value = "10"),
                    @HystrixProperty(name = "circuitBreaker.sleepWindowInMilliseconds", value = "10000"),
                    @HystrixProperty(name = "circuitBreaker.errorThresholdPercentage",value = "60"),
                    })
    public String PaymentCircuitBreaker(@PathVariable("id") Integer id){
        if(id<0){
            throw new RuntimeException("********** id不能為負(fù)");
        }
        String serialNumber = IdUtil.simpleUUID();
        return Thread.currentThread().getName() + "\t" + serialNumber;
    }
    public String paymentCircuitBreaker_fallback(@PathVariable("id") Integer id){
        return  "id 不能為負(fù):" + id;
************Controller********************
    @GetMapping("/payment/circuit/{id}")
        String result = paymentService.PaymentCircuitBreaker(id);
        log.info(result + "***********");
        return result;

如上所示,當(dāng)訪問paymentCircuitBreaker時,如果id小于零則會有一個運行錯誤,這時候就會通過服務(wù)降級來調(diào)用paymentCircuitBreaker_fallback方法,當(dāng)錯誤的次數(shù)達(dá)到60%的時候(自己設(shè)的),就會出現(xiàn)服務(wù)熔斷,這個時候再訪問id大于零的情況,也會發(fā)生服務(wù)降級,因為開起了服務(wù)熔斷,需要慢慢的恢復(fù)正常.

到此這篇關(guān)于SpringCloud之Hystrix的詳細(xì)使用的文章就介紹到這了,更多相關(guān)SpringCloud Hystrix使用內(nèi)容請搜索腳本之家以前的文章或繼續(xù)瀏覽下面的相關(guān)文章希望大家以后多多支持腳本之家！

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