JAVA使用synchronized与wait,notify实现排它，同步通信

JAVA使用多线程实现上传图片，当上传结束后，再通过另外一个线程告知下载图片结束，这时候就需要用到synchronized以及wait，notify实现排它，同步通信，上传图片时，不允许下载，因为此时图片正在上传。

package com.study;

public class Demo {

  public static void main(String[] args) {
    Demo demo = new Demo();
    final OutPutClass putPutClass = demo.new OutPutClass();
    Thread thread = new Thread(new Runnable() {

      @Override
      public void run() {
        while(true){
          putPutClass.ins();
        }
      }
    });
    thread.start();

    Thread thread2 = new Thread(new Runnable() {

      @Override
      public void run() {
        while(true){
          putPutClass.des();
        }
      }
    });
    thread2.start();
  }

  class OutPutClass{
    private boolean isSync = true;
    public synchronized void ins(){
      try {
        while(!isSync){
          this.wait();
        }
        Thread.sleep(1000L);
      } catch (InterruptedException e) {
        e.printStackTrace();
      }
      System.out.println("正在上传中....");
      isSync = false;
      this.notify();
    }
    public synchronized void des(){
      while(isSync){
        try {
          this.wait();
          Thread.sleep(1000L);
        } catch (InterruptedException e) {
          e.printStackTrace();
        }
      }
      System.out.println("下载结束....");
      isSync = true;
      this.notify();
    }
  }
}