线程：Java主线程等待子线程结束

使用Thread.join()方法：

public class App {

    public static void main(String[] args) {
        testMain();
    }
    
    public static void testMain(){
        //实例化一个子线程
        Thread th = new Thread(new Runnable() {
            
            @Override
            public void run() {
                for(int i=0; i<50; i++){
                    try {
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    System.out.println("我是子线程......"+i);
                }
            }
        });
        
        //子线程开启
        th.start();
        
        //主线程
        for(int i=0; i<10; i++){
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println("主线程："+i);
        }
            
        try {
            //Thread.join
            th.join();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        
        System.out.println("主线程结尾处.....");
    }

}

运行结果：