中断等待用户输入的线程，然后退出应用程序

本文介绍了中断等待用户输入的线程，然后退出应用程序的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我有两个线程运行， userInputThread 等待用户从命令行输入， interrupterThread 试图中断 userInputThread 启动后1秒。显然你不能打断被 System.in 阻塞的线程。另一个答案建议在中断线程之前用 System.in.close（）关闭 System.in 。但是当我运行下面的代码， userInputThread 永远不会中断，应用程序只是挂起而不关闭。

I have two threads running, userInputThread waits for user input from the command line and interrupterThread tries to interrupt userInputThread 1 sec after starting. Obviously you cannot interrupt a thread that is blocked by the System.in. Another answer suggests to close System.in with System.in.close() before interrupting a thread. But when I run the following code, the userInputThread never gets interrupted and the app just hangs without closing.

class InputInterruptionExample { private Thread userInputThread; private Thread interrupterThread; InputInterruptionExample() { this.userInputThread = new Thread(new UserInputThread()); this.interrupterThread = new Thread(new InterrupterThread()); } void startThreads() { this.userInputThread.start(); this.interrupterThread.start(); } private class UserInputThread implements Runnable { public void run() { try { System.out.println("enter your name: "); String userInput = (new BufferedReader(new InputStreamReader(System.in))).readLine(); } catch (IOException e) { System.out.println("Oops..somethign went wrong."); System.exit(1); } } } private class InterrupterThread implements Runnable { public void run() { try { sleep(1000); System.out.println("about to interrupt UserInputThread"); System.in.close(); userInputThread.interrupt(); userInputThread.join(); System.out.println("Successfully interrupted"); } catch (InterruptedException e) { } catch (IOException ex) { System.out.println("Oops..somethign went wrong."); System.exit(1); } } } public static void main(String[] args) { InputInterruptionExample exampleApp = new InputInterruptionExample(); exampleApp.startThreads(); } }

已经有一个类似的问题，但没有任何确定的答案。

There's already a similar question, but there aren't any definite answers.

推荐答案

这解决了这个问题：

class InputInterruptionExample { private UserInputThread userInputRunnable; private Thread userInputThread; private Thread interrupterThread; InputInterruptionExample() { this.userInputRunnable = new UserInputThread(); this.userInputThread = new Thread(userInputRunnable); this.interrupterThread = new Thread(new InterrupterThread()); } void startThreads() { this.userInputThread.start(); this.interrupterThread.start(); } private class UserInputThread implements Runnable { private InputStreamReader isr; private BufferedReader br; UserInputThread() { InputStreamReader isr = new InputStreamReader(System.in); BufferedReader br = new BufferedReader(isr); } public void run() { try { System.out.println("enter your name: "); try{ String userInput = br.readLine(); } catch(NullPointerException e) {} } catch (IOException e) { System.out.println("Oops..somethign went wrong."); System.exit(1); } } public void closeBufferdReader() { try { System.in.close(); } catch (IOException e) { System.out.println("Oops..somethign went wrong in closeBufferdReader() method"); System.exit(1); } } } private class InterrupterThread implements Runnable { public void run() { try { sleep(1000); userInputRunnable.closeBufferdReader(); userInputThread.interrupt(); userInputThread.join(); System.out.println("Successfully interrupted"); } catch (InterruptedException e) {} } } public static void main(String[] args) { InputInterruptionExample exampleApp = new InputInterruptionExample(); exampleApp.startThreads(); } }

更新：当BufferedReader以这种方式拆分时工作：

Update: This only works when BufferedReader is split up this way:

InputStreamReader isr = new InputStreamReader(System.in); BufferedReader br = new BufferedReader(isr); String userInput = br.readLine();

由于某种原因，当readLine（）结构写为oneliner ：

For some reason the interruption does not seem to work when the readLine() structure is written as a oneliner:

this.userInput = (new BufferedReader(new InputStreamReader(System.in))).readLine();

因此，虽然可以中断BufferedReader结构中的线程，以读取用户的输入。

So while it is possible to interrupt the thread in the split-up BufferedReader structure, it is now impossible to read user's input.

如果有人可以显示一种方式来获取用户输入，以及当用户没有及时提供任何输入时中断UserInputThread （当中断器正在休眠时），请执行。

If someone could show a way to be able to get user input as well as interrupt the UserInputThread when the user doesn't provide any input in time (while interrupter is sleeping), please do.