2021-04-20

面想对象的分析(OOA,Object-Orientrd Analysis)

面向对象的设计(OOD, Object-Oriented Design)

面向对象的编程(OOP, OBJECT-Oriented Programming)

面向对象:

两大要素:类和对象

四大特征:封装、继承、多态、抽象

方法的重载:

1 方法的名字必须要求相同

2 参数不同

2.1参数的个数but1行 5行 12行 17行

2.2参数的类型不同 12行和17行函数

2.3参数的顺序不同 12行23行

    参数的类型的顺序相同,但参数的名字不同,不能构成重载。推断出,判断不同函数根据函数的  返回权限 返回值 函数的名字(参数的类型)
   public Phone(){

    }
    //构造方法 包含全部的参数,全参构造方法
    public Phone(double kuandu ,double gaodu ,int zhongliang ,String yanse){
        width = kuandu ;
        height = gaodu ;
        weight = zhongliang ;
        color = yanse ;
    }
//构造函数 构造器 构造方法
    public Phone(double kuandu,double gaodu ,int zhongliang){
        weight = zhongliang ;
        width = kuandu ;
        height = gaodu ;
    }
 public Phone(double kuandu,int gaodu ){
        weight = zhongliang ;
        width = kuandu ;
        height = gaodu ;
    }

 public Phone(double gaodu ,double kuandu,int zhongliang){
        weight = zhongliang ;
        width = kuandu ;
        height = gaodu ;
    }
 public Phone(int gaodu ,double kuandu,int zhongliang){
        weight = zhongliang ;
        width = kuandu ;
        height = gaodu ;
    }
//和23行不呢个构成重载
 public Phone(int gaodu ,int kuandu,int zhongliang){
        weight = zhongliang ;
        width = kuandu ;
        height = gaodu ;
    }

toString()

所有的类都继承Object(对象),因此:所有的类中都有toString()方法为了方便查看,一般都会复写

 public String toString() {
        return "{" + width + "" + color + " " + weight + "}" ;

    }

基本数据类型(byte, short, int ,long float double )使用 ==比较

引用数据类型(数组String) 自定义类,需要使用equals方法比较

 public String toString() {
        return "{" + width + "" + color + " " + weight + "}" ;

    }

基本数据类型(byte, short, int ,long float double )使用 ==比较

引用数据类型(数组String) 自定义类,需要使用equals方法比较

package edu.xcdq;

public class Main {

    public static void main(String[] args) {
        Phone xiaomi11 = new Phone() ;
        xiaomi11.weight = 255;
        xiaomi11.height = 135 ;
        xiaomi11.width = 55 ;
        xiaomi11.color = "color" ;
         Phone iphone = new Phone(56,136,256,"土豪金");
        System.out.println(iphone);
    }
}


 
package edu.xcdq;

/**
 * @qvthor liuwenzheng
 * @date 2021/4/20 14:48
 */
public class Phone {
    public double width ;
    public double height ;
    public int weight ;
    public String color ;
    /*
        构造方法:1一定没有返回值 2 方法的名字必须和类名完全一致
     */
    //无参构造方法,不管写不写,系统都会生成
    public Phone(){

    }
    //构造方法 包含全部的参数,全参构造方法
    public Phone(double kuandu ,double gaodu ,int zhongliang ,String yanse){
        width = kuandu ;
        height = gaodu ;
        weight = zhongliang ;
        color = yanse ;
    }
    public Phone(double kuandu,double gaodu ,int zhongliang){
        weight = zhongliang ;
        width = kuandu ;
        height = gaodu ;
    }
    public Phone(double kuandu,int gaodu ,int zhongliang){
        weight = zhongliang ;
        width = kuandu ;
        height = gaodu ;
    }
    public Phone(int gaodu ,double kuandu,int zhongliang){
        weight = zhongliang ;
        width = kuandu ;
        height = gaodu ;
    }
    public Phone(int gaodu ,int kuandu,int zhongliang){
        weight = zhongliang ;
        width = kuandu ;
        height = gaodu ;
    }

    public void startUp(){
        System.out.println("手机即将开机");
    }
    public void suopin(){
        System.out.println("手机即将锁屏");
    }


    //方法的复写
    public String toString() {
        return "{" + width + "" + color + " " + weight + "}" ;

    }






}

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