线程强制执行 join

◆join合并线程,待此线程执行完成后，再执行其他线程,其他线程阻塞

◆可以想象成插队

package state;

public class TestJoin implements Runnable{

    @Override
    public void run() {
        for (int i = 0; i < 500; i++) {
            System.out.println("线程VIP来了"+i);
        }
    }

    public static void main(String[] args) throws InterruptedException {
        //启动线程
        TestJoin testJoin = new TestJoin();
        Thread thread = new Thread(testJoin);
        thread.start();

        //主线程
        for (int i = 0; i < 100; i++) {
            if(i == 20){
                thread.join();//插队，main线程阻塞
            }
            System.out.println("main"+i);
        }
    }
    }