一、多态定义方法并调用子类特有方法
java
public class Animal {
private String colour;
private int age;
public Animal(){
}
public Animal(int age,String colour){
this.age=age;
this.colour=colour;
}
public String getColour() {
return colour;
}
public void setColour(String colour) {
this.colour = colour;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public void eat(String something){
System.out.println("吃"+something);
}
}
public class Cat extends Animal {
public Cat(){
super();
}
public Cat(int age,String colour){
super(age,colour);
}
public void catchMouse(){
System.out.println("抓老鼠");
}
}
public class Dog extends Animal {
public Dog(){
super();
}
public Dog(int age,String colour){
super(age,colour);
}
public void lookHome(){
System.out.println("看家");
}
}
public class Person {
private String name;
private int age;
public Person() {
}
public Person(String name, int age) {
this.name = name;
this.age = age;
}
/**
* 获取
* @return name
*/
public String getName() {
return name;
}
/**
* 设置
* @param name
*/
public void setName(String name) {
this.name = name;
}
/**
* 获取
* @return age
*/
public int getAge() {
return age;
}
/**
* 设置
* @param age
*/
public void setAge(int age) {
this.age = age;
}
public void KeepPet(Animal animal,String something) {
if(animal instanceof Dog d) {
System.out.println(this.age + "岁的" + this.name + "养了一只" + animal.getAge() + "的" + animal.getColour() + "的狗抱着" + something + "猛吃。");
d.lookHome();
}
else if(animal instanceof Cat d) {
System.out.println(this.age + "岁的" + this.name + "养了一只" + animal.getAge() + "的" + animal.getColour() + "的猫抱着" + something + "猛吃。");
d.catchMouse();
}
}
}
public class Test {
public static void main(String[] args){
Animal dog=new Dog(2,"黑");
Person man=new Person("张三",30);
Person woman=new Person("张四",39);
Cat cat=new Cat(1,"白色");
man.KeepPet(dog,"鸡腿");
woman.KeepPet(cat,"猫粮");
}
}知识点：
对象名 instanceof 类名 d ：
返回 true 或 false，若为true 则将该对象赋值为d，d为对应类。可以通过d调用该类的特有方法。
二、编写带有抽象类的标准JavaBean类
java
package test;
public abstract class Animal {
private String name;
public Animal(){
}
public Animal(String name){
this.name=name;
}
public String getName() {
return name;
}
public void setAge(String name) {
this.name = name;
}
public abstract void eat();
}
package test;
public class Dog extends Animal{
@Override
public void eat(){
System.out.println("吃骨头");
}
}
package test;
public class Frog extends Animal{
@Override
public void eat(){
System.out.println("吃虫子");
}
public Frog(){
super();
}
public Frog(String name){
super(name);
}
}
package test;
public class Sheep extends Animal{
@Override
public void eat(){
System.out.println("吃草");
}
}
package test;
import com.test1.Teacher;
public class Test {
public static void main(String[] args){
Frog frog=new Frog("青蛙王子");
frog.eat(); //吃虫子
}
}三、带有接口和抽象类的标准JavaBean类
java
package test;
public abstract class Person {
private int age;
private String name;
public Person() {
}
public Person(String name,int age) {
this.age = age;
this.name = name;
}
public abstract void work();
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
package test;
public abstract class Coach extends Person{
public Coach(){
super();
}
public Coach(String name,int age){
super(name,age);
}
}
package test;
public abstract class Player extends Person{
public Player(){
super();
}
public Player(String name,int age){
super(name,age);
}
}
package test;
public class BasketBallCoach extends Coach{
public BasketBallCoach(){
super();
}
public BasketBallCoach(String name,int age){
super(name,age);
}
public void work(){
System.out.println("教打篮球");
}
}
package test;
public class BasketBallPlayer extends Player{
public BasketBallPlayer(){
super();
}
public BasketBallPlayer(String name,int age){
super(name,age);
}
@Override
public void work() {
System.out.println("打篮球");
}
}
package test;
public class TennisCoach extends Coach implements SpeakEnglish{
public TennisCoach(){
super();
}
public TennisCoach(String name,int age){
super(name,age);
}
public void work(){
System.out.println("教打乒乓球");
}
@Override
public void speakEnglish() {
System.out.println("教练学英语");
}
}
package test;
public class TennisPlayer extends Player implements SpeakEnglish{
public TennisPlayer(){
super();
}
public TennisPlayer(String name,int age){
super(name,age);
}
@Override
public void work() {
System.out.println("打乒乓球");
}
@Override
public void speakEnglish() {
System.out.println("队员学英语");
}
}
package test;
import com.test1.Teacher;
import java.sql.SQLOutput;
public class Test{
public static void main(String[] args){
BasketBallCoach coach1=new BasketBallCoach("张三教练",40);
TennisCoach coach2=new TennisCoach("李四教练",45);
BasketBallPlayer player1=new BasketBallPlayer("易建联",20);
TennisPlayer player2=new TennisPlayer("张继科",30);
player2.speakEnglish(); //教练学英语
coach2.speakEnglish(); //队员学英语
coach2.work(); //教打乒乓球
coach1.work(); //教打篮球
player1.work(); //打篮球
player2.work(); //打乒乓球
}
}