聊聊线程池的预热

序

本文主要研究一下线程池的预热

prestartCoreThread

java/util/concurrent/ThreadPoolExecutor.java

    /*** Starts a core thread, causing it to idly wait for work. This* overrides the default policy of starting core threads only when* new tasks are executed. This method will return {@code false}* if all core threads have already been started.** @return {@code true} if a thread was started*/public boolean prestartCoreThread() {return workerCountOf(ctl.get()) < corePoolSize &&addWorker(null, true);}

ThreadPoolExecutor定义了prestartCoreThread，用于启动一个核心线程

prestartAllCoreThreads

java/util/concurrent/ThreadPoolExecutor.java

    /*** Starts all core threads, causing them to idly wait for work. This* overrides the default policy of starting core threads only when* new tasks are executed.** @return the number of threads started*/public int prestartAllCoreThreads() {int n = 0;while (addWorker(null, true))++n;return n;}

prestartAllCoreThreads用于启动所有的核心线程

小结

ThreadPoolExecutor提供了prestartCoreThread方法，用于启动一个核心线程，提供了prestartAllCoreThreads方法用于启动所有的核心线程。