Java 实例 - 查看线程是否存活

以下实例演示了如何通过继承 Thread 类并使用 isAlive() 方法来检测一个线程是否存活：

public class TwoThreadAlive extends Thread {
   public void run() {
      for (int i = 0; i < 10; i++) {
         printMsg();
      }
   }

   public void printMsg() {
      Thread t = Thread.currentThread();
      String name = t.getName();
      System.out.println("name=" + name);
   }

   public static void main(String[] args) {
      TwoThreadAlive tt = new TwoThreadAlive();
      tt.setName("Thread");
      System.out.println("before start(), tt.isAlive()=" + tt.isAlive());
      tt.start();
      System.out.println("just after start(), tt.isAlive()=" + tt.isAlive());
      for (int i = 0; i < 10; i++) {
         tt.printMsg();
      }
      System.out.println("The end of main(), tt.isAlive()=" + tt.isAlive());
   }
}

以上代码运行输出结果为：

before start(), tt.isAlive()=false
just after start(), tt.isAlive()=true
name=main
name=Thread
name=main
name=main
name=main
name=main
name=main
name=main
name=main
name=main
name=main
name=Thread
name=Thread
name=Thread
name=Thread
name=Thread
The end of main(), tt.isAlive()=true
name=Thread
name=Thread
name=Thread
name=Thread