Java结束线程的三种方法及该如何选择

public class ThreadSafe extends Thread {
 public volatile boolean exit = false;
 public void run() {
  while (!exit){
   //do work
  }
 }

 public static void main(String[] args) throws Exception { 
  ThreadFlag thread = new ThreadFlag(); 
  thread.start(); 
  sleep(5000); // 主线程延迟5秒 
  thread.exit = true; // 终止线程thread 
  thread.join(); 
  System.out.println("线程退出!"); 
 }
}

public class ThreadInterrupt extends Thread { 
 public void run() { 
  try { 
   sleep(50000); // 延迟50秒 
  } 
  catch (InterruptedException e) { 
   System.out.println(e.getMessage()); 
  } 
 } 
 public static void main(String[] args) throws Exception { 
  Thread thread = new ThreadInterrupt(); 
  thread.start(); 
  System.out.println("在50秒之内按任意键中断线程!"); 
  System.in.read(); 
  thread.interrupt(); 
  thread.join(); 
  System.out.println("线程已经退出!"); 
 } 
}

public class ThreadSafe extends Thread {
 public void run() {
  while (!isInterrupted()) { //非阻塞过程中通过判断中断标志来退出
   try {
    Thread.sleep(5*1000); //阻塞过程捕获中断异常来退出
   } catch (InterruptedException e) {
    e.printStackTrace();
    break; //捕获到异常之后，执行 break 跳出循环
   }
  }
 }
}

public class Main {
 public static void main(String[] args) throws InterruptedException {
  MyThread myThread = new MyThread();
  myThread.start();
  Thread.sleep(3000); // 间隔3秒后
  myThread.stop();  // 结束线程
  System.out.println("结束了");
 }
}