利用redis分佈式鎖 setnx 解決雪崩、穿透、擊穿

``先聊一下概念：

redis雪崩：redis中大面積的key同時過時，致使請求越過redis到mysql 數據庫收到高流量衝擊，掛掉

redis穿透：redis 和mysql 都不存在查詢的key，致使請求越過redis到mysql 數據庫收到高流量衝擊，掛掉

redis 擊穿：redis 中key過時，，致使請求越過redis到mysql 數據庫收到高流量衝擊，掛掉

如何解決能夠利用setnx 命令，下面的demo 用的是springData RedisTemplate

package com.test.one.springboottestpne.utils;

import org.apache.commons.lang3.StringUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import java.util.concurrent.TimeUnit;

/**
* setNx 悲觀鎖 解決雪崩 擊穿 穿透問題
* 事物+監聽 解決秒殺 庫存賣超問題。
*/
@Component
public class RedisLockTest extends Thread {

@Override  
public void run() {  
    try {  
        setNx();  
    } catch (InterruptedException e) {  
        e.printStackTrace();  
    }  
}

@Autowired  
StringRedisTemplate stringRedisTemplate;  
public String setNx() throws InterruptedException {  
    System.out.println(Thread.currentThread().getName()+"開始獲取緩存數據");  
    String key = stringRedisTemplate.opsForValue().get("key");  
    if (StringUtils.isNotBlank(key)){  
        System.out.println(Thread.currentThread().getName()+"開始獲取緩存數據成功，返回");  
        return  key;  
    }  
    System.out.println(Thread.currentThread().getName()+"獲取緩存數據失敗");  
    Boolean aBoolean = stringRedisTemplate.opsForValue().setIfAbsent("1", "1");

    if (aBoolean){  
        System.out.println(Thread.currentThread().getName()+"拿到鎖成功,從新設置緩存");  
        stringRedisTemplate.expire("1",1, TimeUnit.MINUTES);  
        //處理業務邏輯  
        key = stringRedisTemplate.opsForValue().get("key");  
        if (StringUtils.isNotBlank(key)){  
            System.out.println(Thread.currentThread().getName()+"---------返回緩存數據");  
            stringRedisTemplate.delete("1");  
            return  stringRedisTemplate.opsForValue().get("key");  
        }  
        //模擬查詢數據庫  
        Thread.sleep(2000);  
        stringRedisTemplate.opsForValue().set("key","11111111");  
        stringRedisTemplate.delete("1");  
        System.out.println(Thread.currentThread().getName()+"。。。。。。返回緩存數據");  
        return  stringRedisTemplate.opsForValue().get("key");  
    }else {  
        Thread.sleep(500);  
        setNx();  
    }  
    return null;  
}

package com.test.one.springboottestpne;


import com.test.one.springboottestpne.utils.RedisLockTest;
import org.apache.commons.lang3.StringUtils;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.test.context.junit4.SpringRunner;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;


@RunWith(SpringRunner.class)
@SpringBootTest(value = {"classpath:application.properties"})
public class RedisTest {

        @Autowired
        RedisLockTest redisLockTest;


    @Test
    public void redisLock() throws InterruptedException {
        ExecutorService executorService = Executors.newFixedThreadPool(100);
        for (int i = 0;i<100;i++){
            executorService.submit(redisLockTest);
        }
        Thread.sleep(1000000);

    }



}

 

 

}`