java如何判断一个线程是否存活代码实例

通过继承 Thread 类创建线程并使用 isAlive() 方法来检测一个线程是否存活

package com.gaodaima;

public class ThreadAliveTest 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) {
		ThreadAliveTest tt = new ThreadAliveTest();
		tt.setName("Thread");
		System.out.println("执行前, tt.isAlive()=" + tt.isAlive());
		tt.start();
		System.out.println("执行后, tt.isAlive()=" + tt.isAlive());
		for (int i = 0; i < 10; i++) {
			tt.printMsg();
		}
		System.out.println("代码跑完了之后, tt.isAlive()=" + tt.isAlive());
	}
}

package com.gaodaima;

public class ThreadAliveTest 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) {

ThreadAliveTest tt = new ThreadAliveTest();

tt.setName("Thread");

System.out.println("执行前, tt.isAlive()=" + tt.isAlive());

tt.start();

System.out.println("执行后, tt.isAlive()=" + tt.isAlive());

for (int i = 0; i < 10; i++) {

tt.printMsg();

}

System.out.println("代码跑完了之后, tt.isAlive()=" + tt.isAlive());

}

执行结果：

执行前, tt.isAlive()=false
执行后, tt.isAlive()=true
name=main
name=main
name=main
name=main
name=main
name=main
name=main
name=main
name=main
name=main
代码跑完了之后, tt.isAlive()=true
name=Thread
name=Thread
name=Thread
name=Thread
name=Thread
name=Thread
name=Thread
name=Thread
name=Thread
name=Thread