java实体Bean 父子类转换

开发中遇到一个问题，父类转子类问题

public class StudentCityArea  extends Student{

    private static final long serialVersionUID = -4004994377623377635L;
    private String province;
    private String city;
    private String area;
    private String remark;
}

直接使用强转出问题

      Student student=new Student();
      StudentCityArea StudentCityAread123=(StudentCityArea)student;

     Exception in thread "main" java.lang.ClassCastException

解决办法，利用json 转化生成子类，解决问题

 Student student=new Student();
 String studentStr= JSONObject.toJSONString(student);
StudentCityArea studentCityArea
=JSONObject.parseObject(studentStr,StudentCityArea.class);