DistributedLock.java
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package com.java110.utils.lock;
import com.java110.utils.cache.BaseCache;
import com.java110.utils.cache.Jedis;
import java.util.Collections;
import java.util.UUID;
/**
* 分布式事务锁
* add by wuxw 2020-01-11
*/
public class DistributedLock extends BaseCache {
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 int DEFAULT_EXPIRE_TIME = 1000;
private static final Long RELEASE_SUCCESS = 1L;
/**
* 获取UUID
*
* @return
*/
public static String getLockUUID() {
return UUID.randomUUID().toString();
}
/**
* 等待获取锁
*
* @param lockKey 锁
* @param requestId 请求标识
* @return
*/
public static boolean waitGetDistributedLock(String lockKey, String requestId) {
return waitGetDistributedLock(lockKey, requestId, DEFAULT_EXPIRE_TIME);
}
public static boolean waitGetDistributedLock(String lockKey, String requestId, int expireTime) {
Jedis redis = null;
try {
redis = getJedis();
while (true) {
if (tryGetDistributedLock(redis, lockKey, requestId, expireTime)) {
return true;
}
}
} finally {
if (redis != null) {
redis.close();
}
}
}
/**
* 尝试获取分布式锁
*
* @param lockKey 锁
* @param requestId 请求标识
* @param expireTime 超期时间
* @return 是否获取成功
*/
private static boolean tryGetDistributedLock(Jedis redis, String lockKey, String requestId, int expireTime) {
String result = redis.set(lockKey, requestId, SET_IF_NOT_EXIST, SET_WITH_EXPIRE_TIME, expireTime);
if (LOCK_SUCCESS.equals(result)) {
return true;
}
return false;
}
/**
* 释放分布式锁
*
* @param lockKey 锁
* @param requestId 请求标识
* @return 是否释放成功
*/
public static boolean releaseDistributedLock(String lockKey, String requestId) {
Jedis redis = null;
try {
redis = getJedis();
String script = "if redis.call('get', KEYS[1]) == ARGV[1] then return redis.call('del', KEYS[1]) else return 0 end";
Object result = redis.eval(script, Collections.singletonList(lockKey), Collections.singletonList(requestId));
if (RELEASE_SUCCESS.equals(result)) {
return true;
}
return false;
} finally {
if (redis != null) {
redis.close();
}
}
}
}