＜Java 6.7章复习＞

目录

第一章 开宗明义

第二章 面向对象的基础认知

第三章 面向对象特性及封装

第四章 面向对象特性之继承和多态

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第一章 开宗明义

1. 讲解面向对象编程的概念
2. 讲解面向对象三大特征
3. 开发"天气预报"项目

 

第二章 面向对象的基础认知

2-1 介绍类与对象

 

 

 

 

 JAVA创建类的语法:

public class Dog {

    //类的内容

}

 

 创建类的实例对象:

类名 对象名 = new 类名();

 

 

2-2 IDEA创建类与对象 

public class Dog {

​  public static void main(String[] args){

        Dog duoduo - new Dog();

         Dog lucky - new Dog();

}



}

 

 2-3 成员变量

 

 

public class Dog { //创建类

​  
String name;

  int age;//定义整型变量

float weight;//定义浮点型变量
public static void main(String[] args){ //主方法

        Dog duoduo = new Dog(); //转换对象

         Dog lucky = new Dog();

  duoduo.name = "多多";

  duoduo.age = 6;

duoduo.weight = 13.5f;

 Dog lucky = "Lucky";

lucky.age = 3;

lucky.weight = 10.2f;

System.out.println(duoduo.name + "今天" + duoduo.age + "岁了");//输出信息

System.out.println(lucky.name + "体重" + duoduo.age + "千克");//输出信息

}
}

 

 

  2-4 方法的作用

public class MethodSample01 {

  public String isOddNumber(int num) {

  if(num % 2 --- 0)  {

       return "偶数";

} else {

     return "奇数";

}

} 

  public static void main (String[ ] args) {

 /}

int a = 10;

MethodSample01 macthodSample01 = new MethodSampleo1( );

 String r1 = methodSample01.isOddNumber(a);

System.out.println(a + "是" + r1);

int b =5;

System.out.println( b +"是" + r2);

}

}

 

public class MethodSample01 {

  public String isOddNumber(int num) {
System.out.println("原始数字为:" + num);

  if(num % 2 --- 0)  {

       return "偶数";

} else {

     return "奇数";

}

} 

  public static void main (String[ ] args) {

 /}

int a = 10;

MethodSample01 macthodSample01 = new MethodSampleo1( );

 String r1 = methodSample01.isOddNumber(a);

System.out.println(a + "是" + r1);

int b =5;

System.out.println( b +"是" + r2);

}

}

 

第三章 面向对象特性及封装

3-1 packge- 包

 

 创建package-包

 

 

 

 

 

 

 

 

package com.imooc.object.project.sample2;

//import关键字用于导入其他包的类

import   com.imooc.object.project.sample1.PackageSample01;

 public class PackageSample02 {

  public static void main(Strin [ ] args) {

//要使用其他包下的类必须先import导入

   PackageleSample01 packageSample01 = new  PackageleSample01();

}

}

 

 3-2访问修饰符

public class PackageSample01 {

//public代表其他任何类都能访问的成员变量

 public String name;

//private void sayHello() {

   System.out.println("Hello world");

}

  //不写访问修饰符代表是默认修饰符,表示只能被包中其他类访问

 void sayGoodbye () {

  System.out.println("Good bye!");

}

public static void main (String [ ] args) {

   PackageSample01 packageSample01 = new PackageSample01() ;

  packeageSampleo1.satHello();

}

3-3 面向对象特性之封装

 

 

public class Algorithm {



public void sort(int a,int b,int c, int d, int e) {

//冒泡排序算法

  int[ ] arr = {a,b,c,d,e};

 for (int i = 0;i< arr.length - 1-i;i++) {

  for(int j = 0;j arr[j+i]) {

     int temp = arr[j] ;

    arr[j] = arr[j+1]

arr[j+1] = temp;

}  }  }

for(int i = 0 ; i

 

 

 

public class Sorter {

   public static void main (String [ ] args) {

   Algorithm algorithm = new Algorithm();

algorithm.sort (a:77,b:91,c:37,d:66,e:102);

​}

}

 3-4 对成员变量进行读写封装

public class MobileNumber  {

  1 related promble

     public String owner; //所有者

 1 related promble

      public String areaCode = "86";//国家区号

public long mobileNumber;//手机号

//getter方法,getter方法用于读取成员变量的内容

//getter书写格式,public成员变量类型, get成员变量名( ),PS:首字母大写

public String getOwner( ) {

   //this 关键字代表当前对象的...

return this.owner;

}

//setter方法,setter方法用于设置成员变量的内容

//setter书写格式,Public void set成员变量名(新的数据参数)

public void setOwner(String owner) {

  this.owner = owner;

}

}

​

 

public class MobileNumberTestor {

  public static void main(String [ ] args) {

     MobileNumber mobileNumber = new MobileNumber();

  //mobileNumber.owner = "老齐";

   //mobileNumber.areaCode = "84";

}

}

 

 

 

第四章 面向对象特性之继承和多态

4-1 面向对象特性之继承

public class Mark1 {

   protected String title;

protected String color;

protected String movie;

public void description() {

 System.out.println("型号:" + title);

 System.out.println("颜色:" + color);

 System.out.println("首次出现的电影:" + movie);

}

private void fire() {

    System.out.println("利用手臂燃料泵射出火焰")

public static void main(String[ ] args) {

   Mark1 mark1 = new Mark1();

    mark1.color = "银灰色";

mark1.movie = "钢铁侠1";

mark1.description();

mark1.fire;

}

}

​

 

/jextends关键字用于类的继承
//extends关键字后面是"父类"extends关键字前是"子类"
e//子类会继承父类的(default)/protected/public修饰的成员变量与方法
   public class Hulk extends Markl {
     public static void main(string[] args){
       Hulk hulk=new Hulk(); 
       hulk.title="反浩克装甲";
        hulk.color="红色";
        hulk.movie="复仇者联盟3";
        hulk.description();

}}

 

 //extends关键字用于类的继承 
 //extends关键字后面是"父类"extends关键字前是"子类" 
//子类会继承父类的(default)/protected/public修饰的成员变量与方法
   public class Hulk extends Markl { 
   private void repair(){ 
System.out.println("弹射备件替换战损组件");

public static void main(string[] args){
Hulk hulk=new Hulk();
hulk.title="反浩克装甲"; I 
hulk.color="红色";
hulk.movie="复仇者联盟3";
 hulk.description((); 

// hulk.fire(); 

hulk.repair();

}
} 

 

 

public class Mark85 extends Markl{
private void createShield(){
System.out.println("利用纳米技术生成防御护盾");}
public static void main(String[] args){
Mark85 mark85=newMark85(); 
mark85.title="马克85型";
 mark85.color="红色";
mark85.movie-"复仇者联盟4"; 
mark85.description();
 mark85.createShield();

 4-2 面向对象特性之多态

 

 

public class Chinese implements Language{
@Override
public void voice() {
System.out.println("你好,有什么可以帮到您的?");
}
}

public class English implements Languagel
@Override
public void voice() {
System.out.println("Hi,may I help you?");
}
}

 

 public class French implements Language{ verride{
public void voice() {
System.out.println("Comment puis-je me rendre à l'h pital ?");
}
}

public class CustomerService {
public static void main(String[] args){
Language language=new English();
 language.voice();
}}

 

public class CustomerService {
public Language contact (int areaCode){
   if(areaCode==86){
  return new Chinese();
}else if(areaCode33){
  return new French();
}else{
  return new English();

public static void main(String[] args){
Language language=new English();
 language.voice();
Language languagel=new Chinese();
languagel.voice();  
CustomerServicecs=new CustomerService; 
Language language2=cs.contact(areaCode:86); 
language2.voice();
)

 

import com.imooc.objectproject.sample5.system.CustomerService; importcom.imooc.objectprojectsample5.system.Language;
public class Customer {
public static void main(string[] args){
CustomerService customerService=new CustomerService(()
Language lanauaae =customerService.contact(areaCode:33);
language.voice();
}
}

4-4 Arraylist列表类的使用

 

import java.util.ArrayList;
 import java.util.list;
public class ArrayListSample{
public static void main(String[] args){
List bookList=new ArrayList();
}
}

import java.util.ArrayList;
 import java.util.list;
public class ArrayListSample{
public static void main(String[] args){
List bookList=new ArrayList(); 
bookList.add("红楼梦"); 
bookList.add("西游记"); 
bookList.add("水浒传"); 
bookList.add("三国志");
System.outprintln(bookList);
}}

 

import java.util.ArrayList;
 import java.util.list;
public class ArrayListSample{
public static void main(String[] args){
List bookList=new ArrayList(); 
bookList.add("红楼梦"); 
bookList.add("西游记"); 
bookList.add("水浒传"); 
bookList.add("三国志");
System.outprintln(bookList);

bookList.add(index:0,element:"镜花缘");

System.out.println(bookList);
}
}

 

public static void main(String[] args){
//泛型
List bookList=newArraList();
 bookList.add("红楼梦");
 bookList.add("西游记"); 
bookList.add("水浒传");
 bookList.add("三国志");
bookList.add(index:0，element"镜花缘");
System.out.println(bookList); 
String bookName = bookList.get(2);
System.out.println(bookName);
}

 

int size = bookList.size( );

System.out.println(size);

 

 

bookList.remove(index:2);

System.out.println(bookList)

 

 

bookList.remove(index:bookList.size() - 1);

System.out.println(bookList)