Redisson分布式锁解锁异常

问题现象

程序中的redission执行unlock()报错如下：

java.lang.IllegalMonitorStateException: attempt to unlock lock, not locked by current thread by node id:

从报错信息可知：尝试解锁，而不是由当前线程按节点 ID 锁定

问题复现

//获取锁对象
RLock lock = redissonClient.getLock(key);

try{
   //获取锁
   boolean tryLock = lock.tryLock(5, TimeUnit.SECONDS);
   if (!tryLock) {
   //抛出业务异常
   }
}catch(){
    //捕获异常
}finally{
    //解锁
    lock.unlock();
}

排查过程

如上代码，线程无论是否有获取锁，都是需要去执行解锁方法，当线程没有获得锁，执行unlock()就会报java.lang.IllegalMonitorStateException: attempt to unlock lock, not locked by current thread by node id:错误

解决方案

1、在解锁时增加判断

//判断要解锁的key是否已被锁定;判断要解锁的key是否被当前线程持有
if (lock.isLocked() && lock.isHeldByCurrentThread()) {
    lock.unlock();
}

2、优化代码

在执行unlock()确保线程已经获得锁

//获取锁对象
RLock lock = redissonClient.getLock(key);
boolean tryLock;
try {
    tryLock = lock.tryLock(5, TimeUnit.SECONDS);
} catch (InterruptedException e) {
    throw new Exception("获取分布式锁失败，请稍后再试");
}

if (!tryLock) {
    throw new Exception("请稍后再试");
}

try{
   //抛出业务异常
}catch(){
    //捕获异常
}finally{
    //解锁
    lock.unlock();
}