Java中注册进程退出时的清理函数-优快云博客

本文深入探讨了Java中addShutdownHook机制的局限性，并通过实例展示了如何在jvm关闭时执行清理工作。然而，在特定情况下如使用SIGKILL信号终止虚拟机时，无法保证清理函数的执行。

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java里利用addShutdownHook可以添加一个线程,在jvm关闭时调用,执行一些清理工作

public static void main(String[] args) throws InterruptedException {
		Thread shutdownHook = new Thread(new Runnable() {
			@Override
			public void run() {
				System.out.println("jvm going down!do something here!");
			}

		});
		Runtime.getRuntime().addShutdownHook(shutdownHook);

		while (true) {
			TimeUnit.SECONDS.sleep(1);
		}

	}

但是这个线程不能保证总是工作.
[quote]In rare circumstances the virtual machine may abort, that is, stop running without shutting down cleanly. This occurs when the virtual machine is terminated externally, for example with the SIGKILL signal on Unix or the TerminateProcess call on Microsoft Windows. The virtual machine may also abort if a native method goes awry by, for example, corrupting internal data structures or attempting to access nonexistent memory. If the virtual machine aborts then no guarantee can be made about whether or not any shutdown hooks will be run. [/quote]
所以kill -9的时候,就不能保证这个清理函数的执行了