Java中有互斥锁吗? [英] Is there a Mutex in Java?

问题描述

java 中是否有互斥对象或创建一个对象的方法?我问是因为用 1 个许可初始化的信号量对象对我没有帮助.想想这个案例:

Is there a Mutex object in java or a way to create one? I am asking because a Semaphore object initialized with 1 permit does not help me. Think of this case:

try {
   semaphore.acquire();
   //do stuff
   semaphore.release();
} catch (Exception e) {
   semaphore.release();
}

如果第一次acquire发生异常，catch块中的释放会增加许可，信号量就不再是二元信号量了.

if an exception happens at the first acquire, the release in the catch block will increase the permits, and the semaphore is no longer a binary semaphore.

正确的方法是?

try {
   semaphore.acquire();
   //do stuff
} catch (Exception e) {
   //exception stuff
} finally {
   semaphore.release();
}

上面的代码会确保信号量是二进制的吗?

Will the above code ensure that the semaphore will be binary?

推荐答案

查看此页面:http://www.oracle.com/technetwork/articles/javase/index-140767.html

它的模式略有不同，这就是(我认为)您正在寻找的:

It has a slightly different pattern which is (I think) what you are looking for:

try {
  mutex.acquire();
  try {
    // do something
  } finally {
    mutex.release();
  }
} catch(InterruptedException ie) {
  // ...
}

在这种用法中，您只在成功acquire()

In this usage, you're only calling release() after a successful acquire()

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