Java超详细讲解类的继承

//实例1：类的继承，创建个人类Person，在以个人类为父类创建子类学生类Student类。
//filename:A_1.java
import java.io.*;
class Person{
    private String name;
    private int age;
    public Person(){
        System.out.println("调用Person类的构造方法");
    }
    public void setNameAge(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(){
        System.out.println("调用Student类的构造方法");
    }
    public void setDepartment(String department){
        this.department=department;
        System.out.println("我是"+department+"的学生");
    }
}
public class A_1{
    public static void main(String[] args){
        Student stu=new Student();
        stu.setNameAge("张三",18);
        stu.show();
        stu.setDepartment("计算机专业");
      }
    }
/**
调用Person类的构造方法
调用Student类的构造方法
姓名：张三年龄18
我是计算机专业的学生
*/

//实例2：super()调用父类中特定的构造方法
//filename:A_1.java
import java.io.*;
class Person{
    private String name;
    private int age;
    public Person(){
        System.out.println("调用Person类的无参构造方法");
    }
    public Person(String name,int age){
        System.out.println("调用Person类的有参构造方法");
        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(){
        System.out.println("调用Student类的无参构造方法");
    }
    public Student(String name,int age,String department){
        super(name,age);
        this.department=department;
        System.out.println("我是"+department+"的学生");
        System.out.println("调用Student类的有参构造方法");
    }
}
public class A_1{
    public static void main(String[] args){
        Student stu1=new Student();
        Student stu2=new Student("张三",18,"计算机专业");
        stu1.show();
        stu2.show();
    }
}
/**
调用Person类的无参构造方法
调用Student类的无参构造方法
调用Person类的有参构造方法
我是计算机专业的学生
调用Student类的有参构造方法
姓名：null年龄0
姓名：张三年龄18
*/