redis单机部署时实现的分布式锁
/**
* @Author: zqf
* @Description:
* @Date 2021/8/25 10:08
*/
public class DistributedLock {
/**
* 释放锁lua脚本,原子操作:lua脚本是作为一个整体执行的,所以中间不会被其他命令插入。
*/
private final static String RELEASE_LOCK_LUA_SCRIPT = "if redis.call('get', KEYS[1]) == ARGV[1] then return redis.call('del', KEYS[1]) else return 0 end";
private static final Long RELEASE_SUCCESS = 1L;
/**
*
* @param lockId 锁
* @param requestId 请求标识
* @param seconds 过期时间
* @return
*/
public static boolean getLock(RedisTemplate redisTemplate, String lockId, String requestId, long seconds) {
Boolean success = redisTemplate.opsForValue().setIfAbsent(lockId, requestId, seconds, TimeUnit.SECONDS);
return success != null && success;
}
/**
* 释放锁
* @param redisTemplate
* @param lockId 锁
* @param requestId 请求标识
* @return 是否释放成功
*/
public static boolean releaseLock(RedisTemplate redisTemplate, String lockId, String requestId) {
// 指定 lua 脚本,并且指定返回值类型
DefaultRedisScript<Long> redisScript = new DefaultRedisScript<>(RELEASE_LOCK_LUA_SCRIPT,Long.class);
// 参数一:redisScript,参数二:key列表,参数三:arg(可多个)
Long result = (Long) redisTemplate.execute(redisScript, Collections.singletonList(lockId), requestId);
return RELEASE_SUCCESS.equals(result);
}
}