猿创征文｜《Java》【速学】类与继承

一、理解继承的作用并学会使用继承

这边的Dog与下面的Penguin有什么问题呢？如何优化呢
    - name:String
    - health:int
    - love:int
    - strain:String
    ----------------
    + print():void 
    + getName():String
    + getHealth():int
    + getLove():int
    + getStrain():String
    + Dog()
}

package o915;

public class Pernguin {
    - name:String
    - health:int
    - love:int
    - sex:String
    ----------------
    + print():void
    + getName():String
    + getHealth():int
    + getLove():int
    + getSex():String
    +Pernguin()
}

 由此得出：

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 * By SHaoYuDeng.( Tao Mo Si ).Full ownership and all rights reserved.
 * (File. Role):
 * System name: ka
 * 1.The source file [Pernguin.java] belongs to the underlying file.
 * 2.You can only limit the scope of this project [JavaSrc].
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 * Copyright (c) 2022. 9
 * By SHaoYuDeng.( Tao Mo Si ).Full ownership and all rights reserved.
 * @version: 1.0
 * -------------------------------------------------------------------------------
 *
 */
 
package o915;
 
public class Penguin {
    private String name;
    private int height;
    private int wid;
    private String sex;
 
    public Penguin() {
    }
 
    public String getName() {
        return name;
    }
 
    public Penguin setName(String name) {
        this.name = name;
        return this;
    }
 
    public int getHeight() {
        return height;
    }
 
    public Penguin setHeight(int height) {
        this.height = height;
        return this;
    }
 
    public int getWid() {
        return wid;
    }
 
    public Penguin setWid(int wid) {
        this.wid = wid;
        return this;
    }
 
    public String getSex() {
        return sex;
    }
 
    public Penguin setSex(String sex) {
        this.sex = sex;
        return this;
    }
 
    public void print(){
        System.out.println("信息输出："+this.getName()+" "+this.getHeight()+" "+this.getWid());
    }
 
    public Penguin(String name, int height, int wid, String sex) {
 
        super();
        this.name = name;
        this.height = height;
        this.wid = wid;
        this.sex = sex;
 
    }
}
 
 
 
package o915;
 
public class Dog {
    private String name;
    private int height;
    public  int wid;
    // strain
    private String strain;
 
    public Dog(){
    }
 
    public String getName() {
        return name;
    }
 
    public void setName(String name) {
        this.name = name;
    }
 
    public int getHeight() {
        return height;
    }
 
    public void setHeight(int height) {
        this.height = height;
    }
 
    public int getWid() {
        return wid;
    }
 
    public void setWid(int wid) {
        this.wid = wid;
    }
 
    public String getStrain() {
        return strain;
    }
 
    public void setStrain(String strain) {
        this.strain = strain;
    }
 
    public void print(){
        System.out.println("信息输出："+this.getName()+" "+this.getHeight()+" "+this.getWid());
    }
 
    public Dog(String name, int height, String strain){
        this.name = name;
        this.height= height;
        this.strain = strain;
 
 
    }
 
}

 我们可以将重复的代码抽取道【父类】中并使用【继承】来优化设计

可以将dog和penguin里的类提取道Ani里

实列：

Ain文件

package o915.ol;
 
public class Ani {
    // 将demo01包中Dog类和Penguin类中相同的代码提取到这个Animal类中
    private String name;
    private int health;
    private int love;
 
    public Ani() {
    }
 
    public Ani(String name, int health, int love) {
        this.name = name;
        this.health = health;
        this.love = love;
    }
 
    public String getName() {
        return name;
    }
 
    public void setName(String name) {
        this.name = name;
    }
 
    public int getHealth() {
        return health;
    }
 
    public void setHealth(int health) {
        this.health = health;
    }
 
    public int getLove() {
        return love;
    }
 
    public void setLove(int love) {
        this.love = love;
    }
 
    public void print() {
        System.out.println("宠物信息-->昵称：" + this.getName() + "，健康值："
                + this.getHealth() + "，亲密度：" + this.getLove());
    }
 
}
 

Penguin文件

 
 
package o915.ol;
 
public class Penguin extends Ani {
    //定义企鹅类中特有的属性
    private String sex;
 
    public Penguin() {
        super();//表示使用Animal类中的无参构造方法
    }
 
    public Penguin(String name, int health, int love, String sex) {
        super(name, health, love);
        this.sex = sex;
    }
 
    public String getSex() {
        return sex;
    }
 
    public void setSex(String sex) {
        this.sex = sex;
    }
 
    //定义Penguin类中特有的方法
    public void swimming(){
        System.out.println("企鹅会仰泳.......");
    }
 
 
 
}

Dog文件

 
 
package o915.ol;
 
public class Dog extends Ani {
    //在这个Dog类中只定义Dog类中特有的属性和方法，原来和Penguin类中相同的代码在Animal类中,通过继承获取，使用extends关键字来获取
 
    private String strain;
 
    public Dog() {
        super();//表示使用Animal类中的无参构造方法
    }
 
    public Dog(String name, int health, int love, String strain) {
        super(name, health, love);//表示使用Animal类中的有参构造方法
        this.strain = strain;
    }
 
    public String getStrain() {
        return strain;
    }
 
    public void setStrain(String strain) {
        this.strain = strain;
    }
 
    //定义Dog类中特有的方法
    public void eat(){
        System.out.println("狗吃骨头......");
    }
 
    public void printInfo(){
        super.print();
        System.out.println("品种："+this.getStrain());
    }
 
}
 

Test文件

 
 
package o915.ol;
 
public class Test {
 
    public static void main(String[] args) {
        //创建Dog类对象
        Dog dog1 = new Dog();
        dog1.setName("二哈");
        dog1.setHealth(100);
        dog1.setLove(100);
        dog1.setStrain("喵咪");
        //print()方法是Animal类中的
        dog1.print();
        //eat()方法是Dog类中的
        dog1.eat();
        dog1.printInfo();
 
        Penguin p1 = new Penguin("企鹅", 99, 88, "公");
        //print()方法是Animal类中的
        p1.print();
        //swimming()是Penguin类中的
        p1.swimming();
 
 
    }
 
}
 

信息台输出：

宠物信息-->昵称：二哈，健康值：100，亲密度：100
狗吃骨头......
宠物信息-->昵称：二哈，健康值：100，亲密度：100
品种：喵咪
宠物信息-->昵称：企鹅，健康值：99，亲密度：88
企鹅会仰泳.......

可以看到继承关系的复杂与好处，设顶的子类可以继承设置好的父类，从而获得信息的汇总与分发