java Runtime ShutDownHook说明

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java Runtime ShutDownHook说明

 

应用：程序正常执行完毕、异常退出、强制退出（system.exit()）时调用预定义的操作

 

 

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相关类

 

Runtime

public class Runtime {

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构造函数

    private Runtime() {}

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相关方法

    public static Runtime getRuntime() {
        return currentRuntime;
    }

    public void addShutdownHook(Thread hook) {
        SecurityManager sm = System.getSecurityManager();
        if (sm != null) {
            sm.checkPermission(new RuntimePermission("shutdownHooks"));
        }
        ApplicationShutdownHooks.add(hook);
    }

 

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示例：System.exit(int status)

 

public class Test {

    public static void main(String[] args){
        Runtime.getRuntime().addShutdownHook(new Thread(()->{
            System.out.println("shutdown hook："+System.currentTimeMillis());
        }));

        System.out.println(Thread.currentThread().getName()+"开始运行："+System.currentTimeMillis());
        System.exit(0);
        System.out.println(Thread.currentThread().getName()+"运行结束："+System.currentTimeMillis());

        try{
            Thread.sleep(1000);
        }catch (Exception e){
            e.printStackTrace();
        }
    }
}

 

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相关输出

 

main开始运行：1584606724420
shutdown hook：1584606724438

 

 

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示例：程序正常退出

 

public class Test {

    public static void main(String[] args){
        Runtime.getRuntime().addShutdownHook(new Thread(()->{
            System.out.println("shutdown hook："+System.currentTimeMillis());
        }));

        System.out.println(Thread.currentThread().getName()+"开始运行："+System.currentTimeMillis());
        System.out.println(10/20);
        System.out.println(Thread.currentThread().getName()+"运行结束："+System.currentTimeMillis());

        try{
            Thread.sleep(1000);
        }catch (Exception e){
            e.printStackTrace();
        }
    }
}

 

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相关输出

 

main开始运行：1584606937250
0
main运行结束：1584606937266
shutdown hook：1584606938266

 

 

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示例：程序异常退出

 

public class Test {

    public static void main(String[] args){
        Runtime.getRuntime().addShutdownHook(new Thread(()->{
            System.out.println("shutdown hook："+System.currentTimeMillis());
        }));

        System.out.println(Thread.currentThread().getName()+"开始运行："+System.currentTimeMillis());
        System.out.println(10/0);
        System.out.println(Thread.currentThread().getName()+"运行结束："+System.currentTimeMillis());

        try{
            Thread.sleep(1000);
        }catch (Exception e){
            e.printStackTrace();
        }
    }
}

 

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相关输出

 

main开始运行：1584607007657
shutdown hook：1584607007676
Exception in thread "main" java.lang.ArithmeticException: / by zero
	at lifecycle.Test.main(Test.java:11)