java Runtime ShutDownHook说明

分手后的思念是犯贱 2023-07-17 02:53 5阅读 0赞

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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 {
    
    ********
    构造函数
    
        private Runtime() {}
    
    ********
    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)