如何在调用解锁之前发生异常时解锁ReentrantLock对象

Question

在下面，如果异常发生在syncMethod2（）那么我如何解锁锁定对象？

public class ReEntrantLock {
ReentrantLock lock = new ReentrantLock();

void syncMethod1() {
  lock.lock();
  syncMethod2(); // throw new NullPointerException();
  lock.unlock();
}

}

Answer 1

public class ReEntrantLock {
    ReentrantLock lock = new ReentrantLock();

    void syncMethod1() {
        lock.lock();
        try {
            syncMethod2();
        } finally {
            lock.unlock();
        }
    }

}

它就在documentation ...

中

Answer 2

您使用try - finally：

lock.lock();
try {
    syncMethod2(); // throw new NullPointerException();
} finally {
    lock.unlock();
}

该模式也在the ReentrantLock JavaDoc中描述。