JAVA多线程使用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();
}
}
}