java多态范例

package com.learnjava.gj.oop;

/**

• USER : JACK
• DATE : 2021/11/20 19:36
• DESC : Person类是父类

*/
public class Person {
//成员变量 挂接到实例上 讲实例属性进行封装，通过特定方法进行访问
private String name;
private int age;

//构造方法
public Person(String name,int age){
    this.name = name;
    this.age = age;
}

//getter and setter

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public int getAge() {
    return age;
}

public void setAge(int age) {
    this.age = age;
}



//成员方法
public void showInfo(){
    System.out.println(this.name + " is "+this.age+" years old!");
}

}

Student

package com.learnjava.gj.oop;

/**

• USER : JACK

• DATE : 2021/11/20 19:40

• DESC :学生子类 继承Person类部分方法和属性
  */
  public class Student extends Person{
  //独有属性
  private String school;

  //构造方法
  public Student(String name,int age,String school){
  super(name,age);
  this.school = school;
  }
  @Override
  //重写父类showInfo()方法
  public void showInfo(){
  System.out.println(this.getName() + " is "+this.getAge()+" years old!,学校是："+this.school);
  }
  }

MainTest

package com.learnjava.gj.oop;

/**

• USER : JACK
• DATE : 2021/11/20 19:47
• DESC :
  */
  public class MainTest {
  public static void showInfoP(Person p){
  if(p instanceof Student){
  p = (Student) p;
  p.showInfo();
  }else{
  p.showInfo();
  }
  }
  public static void main(String[] args) {
  Student p = new Student("jack",12,"北高");
  Person p1 = new Person("bob",23);
  showInfoP(p1);
  showInfoP(p);
  }

}