redis锁机制介绍与实例

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);
  }
  /**
   * 给target上锁
   * @param target
   **/
  public static void lock(Object target) {
    //获取jedis
    Jedis jedis = pool.getResource();
    //result接收setnx的返回值，初始值为0
    Long result= 0L;
    while (result < 1) {
      //如果target在redis中已经存在，则返回0；否则，在redis中设置target键值对，并返回1
      result = jedis.setnx(target.getClass().getName() + target.hashCode(), Thread.currentThread().getName());
    }
    jedis.close();
  }
  /**
   * 给target解锁
   * @param target
   **/
  public static void unLock(Object target) {
    Jedis jedis = pool.getResource();
    //删除redis中target对象的键值对
    Long del = jedis.del(target.getClass().getName() + target.hashCode());
    jedis.close();
  }
  /**
   * 尝试给target上锁，如果锁成功返回true，如果锁失败返回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() {
    //上锁
    RedisLock.lock(this);
    System.out.println("当前线程: " + Thread.currentThread().getName());
    System.out.println("开始执行: " + this.hashCode());
    try {
      System.out.println("doing...");
      Thread.sleep(2000);
    } catch (InterruptedException e) {
      e.printStackTrace();
    }
    System.out.println("完成: " + this.hashCode());
    //解锁
    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();
    }
  }
}