线程的join方法

Java线程之join方法详解

最新推荐文章于 2025-06-22 12:23:47 发布

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本文通过示例代码详细解析了Java中线程的join方法的使用方式及其效果，展示了如何利用join方法来控制线程间的执行顺序。

package fighting;

public class ThreadJoin {

	/**
	 * join方法：
	 * 当A线程执行到了B线程的join方法时，A就会等待，等B线程都执行完，A才会执行。
	 * 
	 *  join方法可以用来临时加入线程执行。
	 * 
	 */
	public static void main(String[] args) throws InterruptedException {
		JoinDemo jd = new JoinDemo();
		Thread t1 = new Thread(jd);
		Thread t2 = new Thread(jd);

		t1.start();
//①		t1.join();//主线程往下执行的过程中，t1要申请加入的运行的线程，也就是申请cpu执行权，这时主线程就会处于冻结状态了。t1就开始执行了，t1就循环70次，t1结束后主线程才会执行。
		          //一个线程在运行过程中，临时加入一个线程，等这个线程执行完，原线程再继续执行。
		t2.start();
//②		t1.join();//这句话放在这里，当主线程执行到这里，就会释放执行权，而这时t1、t2都是运行状态，这时t1、t2就会交替执行，等t1执行完了，不管t2是否执行完，主线程就会继续执行。
		for(int x=0;x<15;x++){
			System.out.println("main..."+x);
		}
		System.out.println("over");
	}

}
class JoinDemo implements Runnable{

	public void run() {
		for(int x=0;x<10;x++){
			System.out.println(Thread.currentThread().getName()+"..."+x);
		}
		
	}
	
}

没有join方法的执行结果：3个线程交替执行

main...0
Thread-1...0
Thread-0...0
main...1
Thread-1...1
Thread-0...1
main...2
Thread-1...2
Thread-0...2
main...3
Thread-1...3
Thread-0...3
main...4
Thread-1...4
Thread-0...4
main...5
Thread-1...5
Thread-0...5
main...6
Thread-1...6
Thread-0...6
main...7
Thread-1...7
Thread-0...7
main...8
Thread-1...8
Thread-0...8
main...9
Thread-1...9
Thread-0...9
main...10
main...11
main...12
main...13
main...14
over
①的执行结果：t1执行完了，主线程继续执行。

Thread-0...0
Thread-0...1
Thread-0...2
Thread-0...3
Thread-0...4
Thread-0...5
Thread-0...6
Thread-0...7
Thread-0...8
Thread-0...9
main...0
Thread-1...0
main...1
Thread-1...1
main...2
Thread-1...2
main...3
Thread-1...3
main...4
Thread-1...4
main...5
Thread-1...5
main...6
Thread-1...6
main...7
Thread-1...7
main...8
Thread-1...8
main...9
Thread-1...9
main...10
main...11
main...12
main...13
main...14
over
②的执行结果：t1，t2交替执行，等t1执行完了，主线程继续执行。

Thread-0...0
Thread-0...1
Thread-0...2
Thread-1...0
Thread-0...3
Thread-1...1
Thread-0...4
Thread-1...2
Thread-0...5
Thread-1...3
Thread-0...6
Thread-1...4
Thread-0...7
Thread-1...5
Thread-0...8
Thread-0...9
Thread-1...6
Thread-1...7
Thread-1...8
Thread-1...9
main...0
main...1
main...2
main...3
main...4
main...5
main...6
main...7
main...8
main...9
main...10
main...11
main...12
main...13
main...14
over