父类作为方法的形参以及父类作为方法返回值

1、父类作为方法的形参

语句：修饰符 父类类型 方法名(){}

2、父类作为方法返回值

语句：修饰符 void/返回值类型 方法名(父类类型 形参名){}

代码例子：

动物类：

/*** @author Mr.Wang* 宠物类**/
public abstract class Animals {private int health;//健康值private int love;//亲密度private String name;//名字public int getHealth() {return health;}public void setHealth(int health) {if(health<0||health>100){//System.out.println("健康值应该在0至100之间，默认值为60。");this.health=60;return;}this.health = health;}public int getLove() {return love;}public void setLove(int love) {this.love = love;}public String getName() {return name;}public void setName(String name) {this.name = name;}public Animals() {}public Animals(int health, int love, String name) {if(health<0||health>100){System.out.println("健康值应该在0至100之间，默认值为60。");this.health=60;}else {this.health = health;}this.love = 60;this.name = name;}//宠物自白public void print() {System.out.println("宠物的自白：");System.out.println("我的名字叫"+this.getName()+"，健康值是"+this.getHealth()+",初始亲密度为"+this.getLove());}public void play() {};public void Bath() {System.out.println("主人正在给"+this.getName()+"洗澡");}
}

企鹅类：

/*** @author Mr.Wang* 企鹅类**/
public class Penguin extends Animals{private String sex;public Penguin() {}public Penguin(int health, int love, String name,String sex) {super(health, love, name);this.sex = sex;}public String getSex() {return sex;}public void setSex(String sex) {this.sex = sex;}public void print() {super.print();System.out.println("我是一只"+this.sex+this.getName());}public void play() {    System.out.println("主人在跟"+this.getName()+"玩水");}
}

狗狗类：

/*** @author Mr.Wang* 狗狗类**/
public class Dog extends Animals{private String type;public Dog() {}public Dog(int health, int love, String name,String type) {super(health, love, name);this.type = type;}public String getType() {return type;}public void setType(String type) {this.type = type;}public void print() {super.print();System.out.println("我是一只"+this.type);}public void play() {System.out.println("主人正在跟"+this.getName()+"玩飞盘");}
}

主人类：

public class Master {public Animals toPlay(int num) {if(num == 1) {return new Dog(90,90,"皮蛋","拉布拉多");}else {return new Penguin(90,90,"小胡","Q仔");}}public void toBath(Animals animals) {animals.Bath();}}

测试类：

public class Text03 {public static void main(String[] args) {Master master = new Master();Animals animals = master.toPlay(1);animals.play();master.toBath(animals);}
}

测试运行结果：