Thread的join()方法

关于Thread实例的join代表的含义,先直接看代码和运行结果

public class Main {

public static void main(String[] args) {

DemoRunnable demo1 = new DemoRunnable(null);

Thread t1 = new Thread(demo1,"thread-demo-1");

DemoRunnable demo2 = new DemoRunnable(t1);
Thread t2 = new Thread(demo2,"thread-demo-2");
Thread t3 = new Thread(demo2,"thread-demo-3");
t1.start();
t2.start();
t3.start();

}

static class DemoRunnable implements Runnable{
private Thread t;
public DemoRunnable(Thread t){
this.t= t;
}
@Override
public void run() {
if(t != null){
try {
t.join();
} catch (InterruptedException e) {
e.printStackTrace();
}
}

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

}
}

运行结果:

thread-demo-1 0

thread-demo-1 1

thread-demo-1 2

thread-demo-1 3

thread-demo-1 4

thread-demo-1 5

thread-demo-1 6

thread-demo-1 7

thread-demo-1 8

thread-demo-1 9

thread-demo-3 0

thread-demo-2 0

thread-demo-2 1

thread-demo-3 1

thread-demo-3 2

thread-demo-2 2

thread-demo-3 3

thread-demo-2 3

thread-demo-3 4

thread-demo-2 4

thread-demo-3 5

thread-demo-2 5

thread-demo-3 6

thread-demo-2 6

thread-demo-3 7

thread-demo-2 7

thread-demo-3 8

thread-demo-2 8

thread-demo-3 9

thread-demo-2 9

由此可以分析知:join的意思是,告诉其他的线程,我正在执行,执行完毕后你在执行.join()方法提高了当前线程的优先级,一直抢占着CpU