Redis的SETNX命令的简单分布式锁实现的Java示例

首先，确保你已经引入了Jedis这个Java Redis客户端库。你可以通过Maven或Gradle来添加依赖。

1、Maven依赖

<dependency><groupId>redis.clients</groupId><artifactId>jedis</artifactId><version>3.7.0</version>
</dependency>

2、Java代码示例

import redis.clients.jedis.Jedis;
import java.util.UUID;
import java.util.concurrent.TimeUnit;public class RedisDistributedLock {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";private static final Long RELEASE_SUCCESS = 1L;/*** 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 tryGetDistributedLock(Jedis jedis, String lockKey, String requestId, int expireTime) {String result = jedis.set(lockKey, requestId, SET_IF_NOT_EXIST, SET_WITH_EXPIRE_TIME, expireTime);return LOCK_SUCCESS.equals(result);}/*** 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 releaseDistributedLock(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));return RELEASE_SUCCESS.equals(result);}public static void main(String[] args) {Jedis jedis = new Jedis("localhost", 6379);String lockKey = "myLock";String requestId = UUID.randomUUID().toString();int expireTime = 10 * 1000;try {if (tryGetDistributedLock(jedis, lockKey, requestId, expireTime)) {try {// 获取到锁，执行业务逻辑System.out.println("执行业务逻辑...");TimeUnit.SECONDS.sleep(5);} finally {releaseDistributedLock(jedis, lockKey, requestId);}} else {// 没有获取到锁，执行其他逻辑System.out.println("未获取到锁，执行其他逻辑...");}} finally {if (jedis != null) {jedis.close();}}}
}

上述代码中，tryGetDistributedLock方法用于尝试获取分布式锁。它使用Redis的SET命令来实现，并通过NX和PX选项来确保只有在锁不存在时设置锁，并设置锁的过期时间。
releaseDistributedLock方法用于释放分布式锁，它使用Redis的Lua脚本来确保只有锁的持有者才能释放锁。