package com.a007;

public class StuNo
{
   //静态私有成员变量
   private static StuNo instance=null;
   private String no;
   //私有构造方法
   private StuNo()
   {  
   }
   //静态公有工厂方法，返回唯一实例
   public static StuNo getInstance()
   {
      if(instance==null)
      {
         System.out.println("新学号");
          instance=new StuNo();
          instance.setStuNo("20194074");
      }
      else
      {
         System.out.println("学号重复，获得旧学号");
      }
      return instance;
   }
   
   private void setStuNo(String no)
   {
       this.no=no;
   }
   
   public String getStuNo()
   {
      return this.no;
   }
   
}