Stop the thread after a particular time

问题

I want to stop my thread after particular time. Here with i added my sample code. Any one of the thread takes more than 6 seconds means i want to stop the particular thread. Rest of the thread should not be affected. Do i need to use the Timer or some better way can we achieve? Suppose if i used Timer means do i need to create new timer for each thread and do i need to cancel the timer suppose if the job finished before 6secs?

    class MyRunnableThread implements Runnable{

    public static int myCount = 0;
    private String fname = null;
    public MyRunnableThread(String fname){
         this.fname = fname;
    }
    public void run() {

            try{
                //read the content based on text and peforms the operation
                //File.read(this.fname)
                System.out.println("Run method stuff"+ this.fname);
            } catch (Exception iex) {
                System.out.println("Exception in thread: "+iex.getMessage());
            }
    }

}

public class RunMyThread {

    public static void main(String a[]){
        System.out.println("Starting Main Thread...");

        String[] fname = {"file1.txt","file2.txt","file3.txt","file4.txt","file5.txt"};
         for(int i=0;i<5;i++){
            try{
                MyRunnableThread mrt = new MyRunnableThread(fname[i]);
                Thread t = new Thread(mrt);
                System.out.println("Main Thread start "+i);
                t.start();

                //stop the thread support run method takes more than 6seconds
                System.out.println("Main Thread end "+ i );
            } catch (Exception iex){
                System.out.println("Exception in main thread: "+iex.getMessage());
            }
        }
        System.out.println("End of Main Thread...");
    }
}

回答1:

User a Timer and a flag to tell the thread to stop:

public class MyRunnableThread implements Runnable {

    boolean run = true;

    String fname;

    public MyRunnableThread(String fname) {
        this.fname = fname;
    }

    public void setRun(boolean toSet) {
        run = false;
    }

    public void run() {
        while (run) {
            doStuff();
        }
    }

    private void doStuff() {
//       File.read(fname);
    }
}

How to use it:

import java.util.Timer;
import java.util.TimerTask;

public class Tester {

    public static void main(String args[]) {

        String[] fname = { "file1.txt", "file2.txt", "file3.txt", "file4.txt", "file5.txt" };
        for (int i = 0; i < 5; i++) {
            try {

                MyRunnableThread mrt = new MyRunnableThread(fname[i]);
                Thread t = new Thread(mrt);
                t.start();

                final Timer timer = new Timer();
                timer.scheduleAtFixedRate(new TimerTask() {
                    int i = 6; // Time in seconds

                    public void run() {
                        System.out.println(i--);
                        if (i < 0) {
                            timer.cancel();
                            mrt.setRun(false);
                        }
                    }
                }, 0, 1000);

            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
}

Change i to whatever time in seconds you want

回答2:

One thought would be you have an ArrayList containing all your threads.

Then you make each thread have an extra field (Timestamp started)

Then you have a timer looping through the Arraylist and stopping the threads where started > 6 seconds ago

回答3:

Well.. there're a lot of ways to do it, I'll explain you one of those.

You can create a custom class that extends Thread and then implement the method run() and CancelCurrentThread(), your run will start the Thread and CancelCurrentThread() will stop it ignoring the exceptions.

Then your code should look like :

mCustomThread thread = new mCustomThread(parametres_if_you_need);
thread.start(); //Start the Thread
thread.join(6000);  //Adding 6 seconds
//You can detect if the 6 seconds have passed or not for example using a timer, then if it joins on this if condition you can call
thread.CancelCurrentThread();

来源：https://stackoverflow.com/questions/36151503/stop-the-thread-after-a-particular-time