1 public class FlagThread extends Thread { 2 /** 3 * 退出标识 4 */ 5 public volatile boolean exit = false; 6 7 @Override 8 public void run() { 9 while (!exit) { 10 } 11 System.out.println("ThreadFlag线程退出"); 12 } 13 14 public static void main(String[] args) throws Exception { 15 FlagThread threadFlag = new FlagThread(); 16 threadFlag.start(); 17 // 主线程延迟3秒 18 sleep(3000); 19 // todo 终止线程thread 20 threadFlag.exit = true; 21 // main线程放弃cpu使用权 22 // 让threadFlag线程继续执行，直到threadFlag运行完 23 threadFlag.join(); 24 System.out.println("线程退出!"); 25 } 26 }
通过第5行的exit属性来表示线程是否应该退出；但这种方法有一个弊端，若线程阻塞时标识便不起作用了。
1 public class InterruptThread extends Thread { 2 /** 3 * 退出标识 4 */ 5 volatile boolean exit = false; 6 7 @Override 8 public void run() { 9 while (!exit) { 10 System.out.println(getName() + " is running"); 11 try { 12 Thread.currentThread().join(); 13 } catch (InterruptedException e) { 14 System.out.println("week up from block..."); 15 // 在异常处理代码中修改共享变量的状态 16 exit = true; 17 } 18 } 19 System.out.println(getName() + " is exiting..."); 20 } 21 22 public static void main(String[] args) throws InterruptedException { 23 InterruptThread interruptThread = new InterruptThread(); 24 System.out.println("Starting thread..."); 25 interruptThread.start(); 26 Thread.sleep(3000); 27 System.out.println("Interrupt thread...: " + interruptThread.getName()); 28 // 设置退出标识为true 29 interruptThread.exit = true; 30 interruptThread.interrupt(); 31 // 主线程休眠3秒以便观察线程interruptThread的中断情况 32 Thread.sleep(3000); 33 System.out.println("Stopping application..."); 34 } 35 }
若第30行注释，则在运行到第12行交出子线程InterruptThread的CPU使用权后，主线程执行完毕，此时便会阻塞子线程；导致29行的标识无用。
此中情况只需要主动的中断线程即可（第30行代码）。
public class InterruptThread extends Thread {
/**
* 退出标识
*/
volatile boolean exit = false;
@Override
public void run() {
while (!exit) {
System.out.println(getName() + " is running");
try {
Thread.currentThread().join();
} catch (InterruptedException e) {
System.out.println("week up from block...");
// 在异常处理代码中修改共享变量的状态
exit = true;
}
}
System.out.println(getName() + " is exiting...");
}
public static void main(String[] args) throws InterruptedException {
InterruptThread interruptThread = new InterruptThread();
System.out.println("Starting thread...");
interruptThread.start();
Thread.sleep(3000);
System.out.println("Interrupt thread...: " + interruptThread.getName());
// 设置退出标识为true
interruptThread.exit = true;
interruptThread.interrupt();
// 主线程休眠3秒以便观察线程interruptThread的中断情况
Thread.sleep(3000);
System.out.println("Stopping application...");
}
}
原文：https://www.cnblogs.com/bzfsdr/p/11565280.html