Redis分布式锁多线程实例

左手的ㄟ右手 2023-06-19 09:40 126阅读 0赞

创建Redis连接工具类

import redis.clients.jedis.Jedis;
    import redis.clients.jedis.JedisPool;
    import redis.clients.jedis.JedisPoolConfig;
    
    public class RedisPool {
        private static JedisPool pool;//jedis连接池
    
        private static int maxTotal = 20;//最大连接数
    
        private static int maxIdle = 10;//最大空闲连接数
    
        private static int minIdle = 5;//最小空闲连接数
    
        private static boolean testOnBorrow = true;//在取连接时测试连接的可用性
    
        private static boolean testOnReturn = false;//再还连接时不测试连接的可用性
    
        static {
            initPool();//初始化连接池
        }
    
        public static Jedis getJedis(){
            return pool.getResource();
        }
    
        public static void close(Jedis jedis){
            jedis.close();
        }
    
        private static void initPool(){
            JedisPoolConfig config = new JedisPoolConfig();
            config.setMaxTotal(maxTotal);
            config.setMaxIdle(maxIdle);
            config.setMinIdle(minIdle);
            config.setTestOnBorrow(testOnBorrow);
            config.setTestOnReturn(testOnReturn);
            config.setBlockWhenExhausted(true);
            pool = new JedisPool(config, "127.0.0.1", 6379, 5000);
        }
    }

创建Redis锁工具类

import redis.clients.jedis.Jedis;
    import java.util.Collections;
    
    public class RedisTool {
        private static final String LOCK_SUCCESS = "OK";
        private static final String SET_IF_NOT_EXIST = "NX";
        private static final String SET_WITH_EXPIRE_TIME = "PX";//Px毫秒，EX秒
    
        /**
         * 尝试获取分布式锁
         * @param jedis Redis客户端
         * @param lockKey 锁
         * @param requestId 请求标识
         * @param expireTime 超期时间
         * @return 是否获取成功
         */
        public static boolean Lock(Jedis jedis, String lockKey, String requestId, int expireTime) {
            String result = jedis.set(lockKey, requestId, SET_IF_NOT_EXIST, SET_WITH_EXPIRE_TIME, expireTime);
    
            if (LOCK_SUCCESS.equals(result)) {
                return true;
            }
            return false;
        }
        private static final Long RELEASE_SUCCESS = 1L;
    
        /**
         * 释放分布式锁
         * @param jedis Redis客户端
         * @param lockKey 锁
         * @param requestId 请求标识
         * @return 是否释放成功
         */
        public static boolean unLock(Jedis jedis, String lockKey, String requestId) {
            String script = "if redis.call('get', KEYS[1]) == ARGV[1] then return redis.call('del', KEYS[1]) else return 0 end";
            Object result = jedis.eval(script, Collections.singletonList(lockKey), Collections.singletonList(requestId));
    
            if (RELEASE_SUCCESS.equals(result)) {
                return true;
            }
            return false;
    
        }
    
    
    
    }

多线程测试

import redis.clients.jedis.Jedis;
    
    public class MyThread  extends Thread {
    
        private int count =100;
    
        public void run() {
            Jedis jedis = RedisPool.getJedis();
            while (count>0){
                boolean aa=RedisTool.Lock(jedis,"key","12345",1000);
    
               if(aa)
               {
                  count--;
                  System.out.println(this.currentThread().getName() + " count = " + count);
                  RedisTool.unLock(jedis, "key", "12345");
    
               }
    
            }
    
        }
    
        public static void main(String[] args) {
            MyThread myThread = new MyThread();
            Thread t1 = new Thread(myThread, "t1");
            Thread t2 = new Thread(myThread, "t2");
            Thread t3 = new Thread(myThread, "t3");
            Thread t4 = new Thread(myThread, "t4");
            Thread t5 = new Thread(myThread, "t5");
            t1.start();
            t2.start();
            t3.start();
            t4.start();
            t5.start();
          
        }
    }

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