redis鎖機(jī)制介紹與實(shí)例

package com.fly.lock;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.JedisPoolConfig;
public class RedisLock {
  //初始化redis池
  private static JedisPoolConfig config;
  private static JedisPool pool;
  static {
    config = new JedisPoolConfig();
    config.setMaxTotal(30);
    config.setMaxIdle(10);
    pool = new JedisPool(config, "192.168.233.200", 6379);
  }
  /**
   * 給target上鎖
   * @param target
   **/
  public static void lock(Object target) {
    //獲取jedis
    Jedis jedis = pool.getResource();
    //result接收setnx的返回值，初始值為0
    Long result= 0L;
    while (result  1) {
      //如果target在redis中已經(jīng)存在，則返回0；否則，在redis中設(shè)置target鍵值對，并返回1
      result = jedis.setnx(target.getClass().getName() + target.hashCode(), Thread.currentThread().getName());
    }
    jedis.close();
  }
  /**
   * 給target解鎖
   * @param target
   **/
  public static void unLock(Object target) {
    Jedis jedis = pool.getResource();
    //刪除redis中target對象的鍵值對
    Long del = jedis.del(target.getClass().getName() + target.hashCode());
    jedis.close();
  }
  /**
   * 嘗試給target上鎖，如果鎖成功返回true，如果鎖失敗返回false
   * @param target
   * @return
   **/
  public static boolean tryLock(Object target) {
    Jedis jedis = pool.getResource();
    Long row = jedis.setnx(target.getClass().getName() + target.hashCode(), "true");
    jedis.close();
    if (row > 0) {
      return true;
    }
    return false;
  }
}

package com.fly.test;
import com.fly.lock.RedisLock;
class Task {
  public void doTask() {
    //上鎖
    RedisLock.lock(this);
    System.out.println("當(dāng)前線程: " + Thread.currentThread().getName());
    System.out.println("開始執(zhí)行: " + this.hashCode());
    try {
      System.out.println("doing...");
      Thread.sleep(2000);
    } catch (InterruptedException e) {
      e.printStackTrace();
    }
    System.out.println("完成: " + this.hashCode());
    //解鎖
    RedisLock.unLock(this);
  }
}
public class Demo {
  public static void main(String[] args) {
    Task task = new Task();
    Thread[] threads = new Thread[5];
    for (Thread thread : threads) {
      thread = new Thread(()->{
        task.doTask();
      });
      thread.start();
    }
  }
}