Java basic tutorialThe column introduces helpful cases of encapsulation and inheritance in Java

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1. Code and renderings

1. Encapsulation

Case: Requirements Description
Use encapsulation to implement the penguin class of the electronic pet system to correctly input the health value and intimacy
Ensure the validity of the health value (0 -100), otherwise take the default value of 60
to ensure the effectiveness of intimacy (0-100), otherwise take the default value of 60
The code is as follows (example):

package?work1;

public?class?Dog?{
????private?String?name;
????private?String?sex;
????private?int?love;

????public?String?getName()?{
????????return?name;
????}

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

????public?String?getSex()?{
????????return?sex;
????}

????public?void?setSex(int?sex)?{
????????if(sex==1){
????????????this.sex?=?"Q仔";
????????}else{
????????????this.sex?=?"Q妹";
????????}

????}

????public?int?getLove()?{
????????return?love;
????}

????public?void?setLove(int?love)?{
????????if(love>=0&&love<pre class="brush:php;toolbar:false">package?work1;

public?class?Penguin?{
????private?String?name;
????private?String?sex;
????private?int?health;

????public?String?getName()?{
????????return?name;
????}

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

????public?String?getSex()?{
????????return?sex;
????}

????public?void?setSex(int?sex)?{
????????if(sex==1){
????????????this.sex?=?"Q仔";
????????}else{
????????????this.sex?=?"Q妹";
????????}

????}

????public?int?getHealth()?{
????????return?health;
????}

????public?void?setHealth(int?health)?{
????????if(health>=0&&health<pre class="brush:php;toolbar:false">package?work1;

import?java.util.Scanner;

public?class?Test1?{
????public?static?void?main(String[]?args)?{
????????Scanner?sc?=?new?Scanner(System.in);
????????System.out.println("歡迎您來到寵物店!?\n?請輸入要領(lǐng)養(yǎng)寵物的名字：");
????????String?name?=?sc.next();
????????System.out.println("請選擇要領(lǐng)養(yǎng)的寵物類型：（1.狗狗??2.企鵝）");
????????int?i?=?sc.nextInt();
????????if(i==1){//狗狗
????????????Dog?dog?=?new?Dog();
????????????dog.setName(name);
????????????System.out.println("請選擇狗狗的性別：(1.Q仔??2.Q妹)");
????????????dog.setSex(sc.nextInt());
????????????System.out.println("請輸入狗狗的親密度（1~100之間）：");
????????????dog.setLove(sc.nextInt());

????????????System.out.println("寵物的自白：\n?我的名字叫"+name+",健康值是"+0+",和主人的"?+
????????????????????"親密度是"+dog.getLove()+",我的性別是"+dog.getSex());
????????}else?{//企鵝
????????????Penguin?p?=?new?Penguin();
????????????p.setName(name);
????????????System.out.println("請選擇企鵝的性別：(1.Q仔??2.Q妹)");
?????????????p.setSex(sc.nextInt());
????????????System.out.println("請輸入企鵝的健康值（1~100之間）：");
?????????????p.setHealth(sc.nextInt());
????????????System.out.println("寵物的自白：\n?我的名字叫"+name+",健康值是"+p.getHealth()+",和主人的"?+
????????????????????"親密度是"+0+",我的性別是"+p.getSex());
????????}

????}
}

2. Inheritance

Case: Use inheritance to optimize the electronic pet system, extract the parent class, create a subclass, and use super in the subclass to call the parent class constructor.
The code is as follows (example):

package?work3;

public?class?Dog?extends?Pet?{
????@Override
????public?void?show()?{
????????System.out.println("寵物的自白：\n?我的名字叫"+this.getName()+",健康值是"+0+",和主人的"?+
????????????????"親密度是"+this.getLove()+",我的性別是"+this.getSex());
????}

????private?int?love;

????public?Dog(String?name,?int?sex,?int?love)?{
????????super(name,?sex);
????????this.love?=?love;
????}

????public?int?getLove()?{
????????return?love;
????}

????public?void?setLove(int?love)?{
????????if(love>=0&&love<pre class="brush:php;toolbar:false">package?work3;

public?class?Penguin?extends?Pet?{

????@Override
????public?void?show()?{
????????System.out.println("寵物的自白：\n?我的名字叫"+this.getName()+",健康值是"+this.getHealth()+",和主人的"?+
????????????????"親密度是"+0+",我的性別是"+this.getSex());
????}
????private?int?health;

????public?Penguin(String?name,?int?sex,?int?health)?{
????????super(name,?sex);
????????this.health?=?health;
????}

????public?int?getHealth()?{
????????return?health;
????}

????public?void?setHealth(int?health)?{
????????if(health>=0&&health<pre class="brush:php;toolbar:false">package?work3;

public?class?Pet?{
????private?String?name;
????private?String?sex;

????public?void?show(){

????}

????public?Pet(String?name,?int?sex)?{
????????this.name?=?name;
????????if(sex==1){
????????????this.sex?=?"Q仔";
????????}else{
????????????this.sex?=?"Q妹";
????????}
????}

????public?String?getName()?{
????????return?name;
????}

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

????public?String?getSex()?{
????????return?sex;
????}

????public?void?setSex(int?sex)?{
????????if(sex==1){
????????????this.sex?=?"Q仔";
????????}else{
????????????this.sex?=?"Q妹";
????????}

????}
}

package?work3;

import?java.util.Scanner;

import?static?java.lang.System.out;

public?class?Test2?{
????public?static?void?main(String[]?args)?{
????????Scanner?sc?=?new?Scanner(System.in);
????????out.println("歡迎您來到寵物店!?\n?請輸入要領(lǐng)養(yǎng)寵物的名字：");
????????String?name?=?sc.next();
????????out.println("請選擇要領(lǐng)養(yǎng)的寵物類型：（1.狗狗??2.企鵝）");
????????int?i?=?sc.nextInt();
????????if?(i==1){//狗狗
????????????out.println("請選擇狗狗的性別：(1.Q仔??2.Q妹)");
????????????int?sex=sc.nextInt();
????????????out.println("請輸入狗狗的親密度（1~100之間）：");
????????????Dog?dog?=?new?Dog(name,?sex,?sc.nextInt());
????????????dog.show();
????????}else?{//企鵝
????????????out.println("請選擇企鵝的性別：(1.Q仔??2.Q妹)");
????????????int?sex=sc.nextInt();
????????????out.println("請輸入企鵝的健康值（1~100之間）：");
????????????Penguin?p?=?new?Penguin(name,?sex,?sc.nextInt());
????????????p.show();
????????}
????}
}

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