请求大佬支援!!!报错java.io.NotSerializableException

package com.bjsxt.singleton;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;

public class Client2 implements Serializable{
    private static final long serialVersionUID = 1L;   

    public static void main(String[] args) throws Exception {
        SingletonDemo6 s1 = SingletonDemo6.getInstance();
        SingletonDemo6 s2 = SingletonDemo6.getInstance();
        System.out.println(s1);
        System.out.println(s2);



        //通过反序列化的方式构造多个对象
        FileOutputStream fos = new FileOutputStream("d:/a.txt");
        ObjectOutputStream oos = new ObjectOutputStream(fos);
        oos.writeObject(s1);//序列化
        oos.close();
        fos.close();

        ObjectInputStream ois = new ObjectInputStream(new FileInputStream("d:/a.txt"));
        SingletonDemo6 s3 = (SingletonDemo6) ois.readObject();
        System.out.println(s3);
        ois.close();
    }
}

在你要存储的pojo类(SingletonDemo6)上加implements Serializable，不是在这个类上

实现类要实现Serializable接口