class Person { private String name; private int age; public Person(){ System.out.println("无参构造"); } public void setName(String name,int age){ this.name=name; this.age=age; } public void show(){ System.out.println("姓名="+name+"年龄"+age); } } class Student extends Person { private String department; public Student() { } public void setDepartment(String dep){ department=dep; System.out.println("我是"+department+"的学生"); } } public class Work { public static void main(String[] args){ Student stu=new Student(); stu.setNameAge("张小三",21); stu.show(); stu.setDepartment("计算机系"); ; } }