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  • ShutdownHook作用

    源地址:http://kim-miao.iteye.com/blog/1662550

    void java.lang.Runtime.addShutdownHook(Thread hook)

    该方法用来在jvm中增加一个关闭的钩子。当程序正常退出,系统调用 System.exit方法或虚拟机被关闭时才会执行添加的shutdownHook线程。其中shutdownHook是一个已初始化但并不有启动的线程,当jvm关闭的时候,会执行系统中已经设置的所有通过方法addShutdownHook添加的钩子,当系统执行完这些钩子后,jvm才会关闭。所以可通过这些钩子在jvm关闭的时候进行内存清理、资源回收等工作。  

    public class TestRuntimeShutdownHook {  
        public static void main(String[] args) {  
      
            Thread shutdownHookOne = new Thread() {  
                public void run() {  
                    System.out.println("shutdownHook one...");  
                }  
            };  
            Runtime.getRuntime().addShutdownHook(shutdownHookOne);  
      
            Runnable threadOne = new Runnable() {  
                public void run() {  
                    try {  
                        Thread.sleep(1000);  
                    } catch (InterruptedException e) {  
                        e.printStackTrace();  
                    }  
                    System.out.println("thread one doing something...");  
                }  
            };  
      
            Runnable threadTwo = new Thread() {  
                public void run() {  
                    try {  
                        Thread.sleep(2000);  
                    } catch (InterruptedException e) {  
                        e.printStackTrace();  
                    }  
                    System.out.println("thread two doing something...");  
                }  
            };  
      
            threadOne.run();  
            threadTwo.run();  
        }  
    }  
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  • 原文地址:https://www.cnblogs.com/akaneblog/p/6965386.html
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