Studnet类 package entity; public class Student { public String name; //姓名 public Integer age; //年龄 //无参构造函数 public Student() {} //含参构造函数 public Student(String name, Integer age) { this.name = name; this.age = age; } public String getName() { return name; } public void setName(String name) { this.name = name; } public Integer getAge() { return age; } public void setAge(Integer age) { this.age = age; } //打印学生信息 public void Show() { System.out.println("姓名："+this.getName()+" 年龄："+this.getAge()); } } Undergrated类 package entity; public class Undergraduate extends Student { public String degree; //学位 public Undergraduate(String name,Integer age,String degree) { super(name,age); this.degree = degree; } public String getDegree() { return degree; } public void setDegree(String degree) { this.degree = degree; } public void Show() { System.out.println( "姓名："+this.getName()+" 年龄："+this.getAge()+" 学位："+this.getDegree()); } } 测试类 import entity.Student; import entity.Undergraduate; public class main { public static void main(String[] args) { // TODO 自动生成的方法存根 Student student1=new Student("张三",25); student1.Show(); Undergraduate undergraduate1=new Undergraduate("李四", 20, "博士"); undergraduate1.Show(); } }