java开启多个线程，执行完成后再执行主线程

╰半橙微兮° 2022-09-02 12:59 144阅读 0赞

***代码例子：***

public static void main(String[] args) throws Exception{ 
            int count = 10;
            List<Thread> workers = new ArrayList<>();
            for(int i = 0; i < count; i++) { 
                final int s = i;
                Thread worker = new Thread(new Runnable() { 
                    @Override
                    public void run() { 
                        try { 
                            Thread.sleep(500);
                            System.out.println("执行子线程" + s);
                        }catch (Exception e){ 
    
                        }
                    }
                });
                worker.start();
                workers.add(worker);
            }
            for(int i = 0; i < count; i++) { 
                workers.get(i).join();
            }
            System.out.println("执行主线程");
        }

***结果：***

执行子线程7
    执行子线程6
    执行子线程3
    执行子线程2
    执行子线程9
    执行子线程8
    执行子线程5
    执行子线程4
    执行子线程1
    执行子线程0
    执行主线程

***查看jdk中join源码，你会发现，官方翻译是等待线程死亡，也就是线程执行结束***

/** * Waits for this thread to die. * * <p> An invocation of this method behaves in exactly the same * way as the invocation * * <blockquote> * {@linkplain #join(long) join}{@code (0)} * </blockquote> * * @throws InterruptedException * if any thread has interrupted the current thread. The * <i>interrupted status</i> of the current thread is * cleared when this exception is thrown. */
        public final void join() throws InterruptedException { 
            join(0);
        }