能在这个的基础上实现添加守护线程实现自动续期的功能吗
时间: 2024-03-06 16:49:05 浏览: 83
是的,可以在上面的基础上添加守护线程实现自动续期的功能。在分布式环境下,锁的占用时间可能会比较长,如果锁过期后被其他线程获取,会导致当前线程的操作失败,所以需要自动续期来保证锁的有效性。
以下是添加守护线程实现自动续期的示例代码:
```java
import redis.clients.jedis.Jedis;
import redis.clients.jedis.params.SetParams;
public class DistributedLock {
private Jedis jedis;
private String lockKey;
private String lockValue;
private int expireTime;
private Thread renewThread;
private volatile boolean renewFlag;
public DistributedLock(Jedis jedis, String lockKey, String lockValue, int expireTime) {
this.jedis = jedis;
this.lockKey = lockKey;
this.lockValue = lockValue;
this.expireTime = expireTime;
}
public boolean tryLock(int retryTimes, int retryInterval, int timeout) {
int timeElapsed = 0;
while (timeElapsed < timeout) {
SetParams params = new SetParams();
params.nx();
params.ex(expireTime);
String result = jedis.set(lockKey, lockValue, params);
if ("OK".equals(result)) {
startRenewThread(); // 启动续期线程
return true;
}
timeElapsed += retryInterval;
try {
Thread.sleep(retryInterval);
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
}
}
return false;
}
public void unlock() {
stopRenewThread(); // 停止续期线程
String value = jedis.get(lockKey);
if (lockValue.equals(value)) {
jedis.del(lockKey);
}
}
private void startRenewThread() {
renewFlag = true;
renewThread = new Thread(() -> {
while (renewFlag) {
jedis.expire(lockKey, expireTime);
try {
Thread.sleep(expireTime / 2);
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
}
}
});
renewThread.setDaemon(true);
renewThread.start();
}
private void stopRenewThread() {
renewFlag = false;
if (renewThread != null) {
renewThread.interrupt();
}
}
}
```
在上面的代码中,我们添加了一个守护线程renewThread,用于定时续期锁的过期时间。在tryLock方法中,如果成功获取到锁,则启动守护线程;在unlock方法中,停止守护线程。
守护线程的具体实现是,在renewFlag为true的情况下,每隔expireTime/2的时间,调用jedis.expire方法,将锁的过期时间延长expireTime秒,确保锁的有效性。注意,在启动守护线程时,需要将它设置为守护线程,这样当主线程退出时,它会自动退出,避免出现线程泄露的问题。
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