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Java如何讓線程主動(dòng)讓出 CPU

更新時(shí)間：2026年05月12日 08:37:16 作者：ybwycx

本文主要介紹了Java如何讓線程主動(dòng)讓出 CPU,文中通過(guò)示例代碼介紹的非常詳細(xì),對(duì)大家的學(xué)習(xí)或者工作具有一定的參考學(xué)習(xí)價(jià)值,需要的朋友們下面隨著小編來(lái)一起學(xué)習(xí)學(xué)習(xí)吧

Thread.sleep

sleep 方法可以讓線程主動(dòng)讓出 CPU，但是并不會(huì)釋放鎖。

    /**
     * Causes the currently executing thread to sleep (temporarily cease
     * execution) for the specified number of milliseconds, subject to
     * the precision and accuracy of system timers and schedulers. The thread
     * does not lose ownership of any monitors.
     */
    public static native void sleep(long millis) throws InterruptedException;

Thread.yield

yield 也可以讓線程主動(dòng)讓出 CPU，然后和其他線程一起競(jìng)爭(zhēng) CPU，但是調(diào)度器也可以忽略 yield。哪些情況會(huì)用到 yield 呢？
1. 一般在 debug 和 test 中使用。
2. CPU 密集型應(yīng)用主動(dòng)讓出 CPU 以避免過(guò)度占用 CPU，影響其他任務(wù)。

    /**
     * A hint to the scheduler that the current thread is willing to yield
     * its current use of a processor. The scheduler is free to ignore this
     * hint.
     *
     * <p> Yield is a heuristic attempt to improve relative progression
     * between threads that would otherwise over-utilise a CPU. Its use
     * should be combined with detailed profiling and benchmarking to
     * ensure that it actually has the desired effect.
     *
     * <p> It is rarely appropriate to use this method. It may be useful
     * for debugging or testing purposes, where it may help to reproduce
     * bugs due to race conditions. It may also be useful when designing
     * concurrency control constructs such as the ones in the
     * {@link java.util.concurrent.locks} package.
     */
    public static native void yield();

Thread.currentThread().suspend()

該方法已過(guò)時(shí)。為啥呢？suspend 掛起線程，并不會(huì)釋放鎖，又不像 sleep 那樣一段時(shí)間后自動(dòng)恢復(fù)，所以容易引起死鎖。相對(duì)應(yīng)的 resume 方法用于喚醒一個(gè) suspend 的線程。

    /**
     * Suspends this thread.
     * <p>
     * First, the <code>checkAccess</code> method of this thread is called
     * with no arguments. This may result in throwing a
     * <code>SecurityException </code>(in the current thread).
     * <p>
     * If the thread is alive, it is suspended and makes no further
     * progress unless and until it is resumed.
     *
     * @exception  SecurityException  if the current thread cannot modify
     *               this thread.
     * @see #checkAccess
     * @deprecated   This method has been deprecated, as it is
     *   inherently deadlock-prone.  If the target thread holds a lock on the
     *   monitor protecting a critical system resource when it is suspended, no
     *   thread can access this resource until the target thread is resumed. If
     *   the thread that would resume the target thread attempts to lock this
     *   monitor prior to calling <code>resume</code>, deadlock results.  Such
     *   deadlocks typically manifest themselves as "frozen" processes.
     *   For more information, see
     *   <a href="{@docRoot}/../technotes/guides/concurrency/threadPrimitiveDeprecation.html" rel="external nofollow" >Why
     *   are Thread.stop, Thread.suspend and Thread.resume Deprecated?</a>.
     */
    @Deprecated
    public final void suspend() {
        checkAccess();
        suspend0();
    }

    @Deprecated
    public final void resume() {
        checkAccess();
        resume0();
    }