如何等待并通知工作？

问题描述

我需要知道wait（）和notify（）是如何工作的？我无法通过使用wait（）和notify（）来实现它的工作。相反，如果我使用while（）循环进行等待，它可以正常工作。怎么回事？为什么我不能简单地使用wait（）和notify（）？

I need to know how wait() and notify() works exactly? I couldn't achieve its working by using wait() and notify() as such. Instead if I use a while() loop for wait, it works properly. How is it so? Why can't I use just wait() and notify() simply?

推荐答案

你读过等待 - 功能？

have you read the documentation of the wait-notify functions ?

无论如何，为了实现等待通知机制的最佳方法，使用类似的东西（基于）：

anyway, for the best way to achieve a wait-notify mechanism, use something like this (based on this website) :

public class WaitNotifier {
    private final Object monitoredObject = new Object();
    private boolean wasSignalled = false;

    /**
     * waits till another thread has called doNotify (or if this thread was interrupted), or don't if was already
     * notified before
     */
    public void doWait() {
        synchronized (monitoredObject) {
            while (!wasSignalled) {
                try {
                    monitoredObject.wait();
                } catch (final InterruptedException e) {
                    break;
                }
            }
            wasSignalled = false;
        }
    }

    /**
     * notifies the waiting thread . will notify it even if it's not waiting yet
     */
    public void doNotify() {
        synchronized (monitoredObject) {
            wasSignalled = true;
            monitoredObject.notify();
        }
    }

}

做注意事项，该类的每个实例只应使用一次，因此如果需要多次使用它，可能需要更改它。

do note, that each instance of this class should be used only once, so you might want to change it if you need to use it multiple times.

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