java设计模式——结构型模式(上)

结构型模式：

1. 适配器模式

2. 桥接模式

3. 装饰模式

4. 组合模式

5. 外观模式

6. 享元模式

7. 代理模式

适配器模式

例：普通电源是220V，手机充电需要5V，需要一个适配器将电源电压转换。

• 将220V对象交给电压转换器

• 将电压转换器交给手机的充电方法

IVoltage5V

package com.company.demo06adapter;

public interface IVoltage5V {
    public int output5V();
}

Voltage220V

package com.company.demo06adapter;

public class Voltage220V {
    public int output() {
        System.out.println("输出220V电压");
        return 220;
    }
}

VoltageAdapter

package com.company.demo06adapter;

public class VoltageAdapter implements IVoltage5V {
    private Voltage220V v;

    public VoltageAdapter(Voltage220V v) {
        this.v = v;
    }

    @Override
    public int output5V() {
        if (v == null) {
            System.out.println("未接插口无法充电");
            return 0;
        } else {
            int output = v.output();
            System.out.println("电源适配");
            System.out.println("适配完成，输出电压为：" + output);
            return output / 44;
        }
    }
}

Phone

package com.company.demo06adapter;

public class Phone {
    void getcharge(IVoltage5V i){
        if (i.output5V()==5){
            System.out.println("成功充电");
        }else {
            System.out.println("电压错误无法充电");
        }
    }
}

Test

package com.company.demo06adapter;

public class Test {
    public static void main(String[] args) {
        Phone p = new Phone();
        p.getcharge(new VoltageAdapter(new Voltage220V()));
    }
}

桥接模式

例：市面上共有三种手机：大屏，中屏，小屏手机，同时有三家手机品牌：xiaomi，oppo，vivo。

Brand

package com.company.demo07bridge;

public interface Brand {
    void type();
}

Oppo

package com.company.demo07bridge;

public class Oppo implements Brand {
    @Override
    public void type() {
        System.out.println("欢迎使用oppo手机");
    }
}

Vivo

package com.company.demo07bridge;

public class Vivo implements Brand {
    @Override
    public void type() {
        System.out.println("欢迎使用vivo手机");
    }
}

Xiaomi

package com.company.demo07bridge;

public class Xiaomi implements Brand {
    @Override
    public void type() {
        System.out.println("欢迎使用xiaomi手机");
    }
}

Cellphone

package com.company.demo07bridge;

public abstract class Cellphone {

    //组合品牌
    private Brand brand;

    //构造器
    public Cellphone(Brand brand) {
        this.brand = brand;
    }

   protected void type(){
        this.brand.type();
    }
}

SmallScreen

package com.company.demo07bridge;


public class SmallScreen extends Cellphone{
    public SmallScreen(Brand brand) {
        super(brand);
    }
    public void type(){
        super.type();
        System.out.println("小屏幕手机");
    }
}

MiddleScreen

package com.company.demo07bridge;

public class MiddleScreen extends Cellphone{
    public MiddleScreen(Brand brand) {
        super(brand);
    }
    public void type(){
        super.type();
        System.out.println("中屏幕手机");
    }
}

BigScreen

package com.company.demo07bridge;


public class BigScreen extends Cellphone {
    public BigScreen(Brand brand) {
        super(brand);
    }

    public void type() {
        super.type();
        System.out.println("大屏幕手机");
    }
}

Test

package com.company.demo07bridge;

public class Test {
    public static void main(String[] args) {
        Cellphone oppo1=new BigScreen(new Oppo());
        oppo1.type();

        Cellphone xiaomi1=new SmallScreen(new Xiaomi());
        xiaomi1.type();
    }
}

装饰模式

一个类可以有很多不同的类进行修饰

例：煎饼，可以加鸡蛋，火腿肠，培根，蔬菜，加不同的东西，会有不同的价格

• 创建一个顾客对象

• 顾客对象购买了相应的产品

HandPancake

package com.company.demo10decorator;

public interface HandPancake {
    /**
     * 提供手抓饼
     */
    String offerHandPancake();
    /**计算手抓饼的价格
     * @return
     */
    Integer calcCost();
}

Decorator

package com.company.demo10decorator.dec;

import com.company.demo10decorator.HandPancake;

/**
 * Created by noteless on 2018/9/6.
 * Description:装饰器类实现了手抓饼接口,具有了手抓饼的类型
 */
public abstract class Decorator implements HandPancake {
    private HandPancake handPancake;
    protected Decorator(HandPancake handPancake){
        this.handPancake = handPancake;
    }
    /**提供手抓饼
     * @return
     */
    @Override
    public String offerHandPancake() {
        return handPancake.offerHandPancake();
    }

    /**提供手抓饼的价格
     * @return
     */
    @Override
    public Integer calcCost() {
        return handPancake.calcCost();
    }
}

Bacon

package com.company.demo10decorator.dec;

import com.company.demo10decorator.HandPancake;

public class Bacon extends Decorator {
    public Bacon(HandPancake handPancake){
        super(handPancake);
    }

    @Override
    public String offerHandPancake() {
        return super.offerHandPancake()+" 加培根";
    }
    @Override
    public Integer calcCost() {
        return super.calcCost()+4;
    }
}

Egg

package com.company.demo10decorator.dec;

import com.company.demo10decorator.HandPancake;

public class Egg extends Decorator {
    public Egg(HandPancake handPancake){
        super(handPancake);
    }
    @Override
    public String offerHandPancake() {
        return super.offerHandPancake()+"加鸡蛋";
    }
    @Override
    public Integer calcCost() {
        return super.calcCost()+2;
    }
}

Sausage

package com.company.demo10decorator.dec;

import com.company.demo10decorator.HandPancake;

public class Sausage extends Decorator {
    public Sausage(HandPancake handPancake){
        super(handPancake);
    }
    @Override
    public String offerHandPancake() {
        return super.offerHandPancake()+" 加香肠";
    }
    @Override
    public Integer calcCost() {
        return super.calcCost()+3;
    }
}

Vegetable

package com.company.demo10decorator.dec;

import com.company.demo10decorator.HandPancake;

public class Vegetable extends Decorator {
    public Vegetable(HandPancake handPancake) {
        super(handPancake);
    }

    @Override
    public String offerHandPancake() {
        return super.offerHandPancake() + " 加青菜";
    }

    @Override
    public Integer calcCost() {
        return super.calcCost() + 1;
    }
}

NotelessHandPancake

package com.company.demo10decorator;

public class NotelessHandPancake implements HandPancake {
    /**
     * 提供noteless 家的手抓饼一份
     */
    @Override
    public String offerHandPancake() {
        return " noteless 家的手抓饼";
    }
    /**计算 noteless 家 一份手抓饼的价格
     * @return
     */
    @Override
    public Integer calcCost() {
        return 3;
    }
}

Customer

package com.company.demo10decorator;

public class Customer {
    private String name;

    Customer(String name) {
        this.name = name;
    }

    public void buy(HandPancake handPancake) {
        System.out.println(name + "购买了 : " + handPancake.offerHandPancake() +
                " 一份, 花了 : " + handPancake.calcCost() + "块钱~");
        System.out.println();
    }
}

Test

package com.company.demo10decorator;


import com.company.demo10decorator.dec.Bacon;
import com.company.demo10decorator.dec.Egg;
import com.company.demo10decorator.dec.Sausage;
import com.company.demo10decorator.dec.Vegetable;

/**
 * 手抓饼3块
 * Sausage 烤肠 3块
 * Bacon 培根 4块
 * Egg 鸡蛋2块
 * Vegetable 青菜 1块
 */

public class Test {
    public static void main(String[] strings) {


//有一个顾客wenwen,他想吃手抓饼了,他加了一根烤肠 又加了培根
        Customer customerC = new Customer("wenwen");
        customerC.buy(new Bacon(new Sausage(new NotelessHandPancake())));

    }
}

组合模式

例：创建文件类，可以是文件夹，图片，文本，视频

File

package com.company.demo09composite;

public abstract class File {
    String name;

    public File(String name){
        this.name=name;
    }
    public String getName() {
        return name;
    }

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

    public abstract void display();
}

Folder

package com.company.demo09composite;

import java.util.ArrayList;
import java.util.List;

public class  Folder extends File {

    private List<File> files;

    public Folder(String name) {
        super(name);
        files=new ArrayList<>();
    }

    @Override
    public void display() {
        for(File file : files){
            file.display();
        }
    }
    public void add(File file){
        files.add(file);
    }

    public void remove(File file){
        files.remove(file);
    }
}

Image

package com.company.demo09composite;

class Image extends File{

    public Image(String name) {
        super(name);
    }

    public void display() {
        System.out.println("这是图像文件，文件名：" + super.getName());
    }
}

Text

package com.company.demo09composite;

public class Text extends File{

    public Text(String name) {
        super(name);
    }

    public void display() {
        System.out.println("这是文本文件，文件名：" + super.getName());
    }
}

Video

package com.company.demo09composite;

public class Video extends File {

    public Video(String name) {
        super(name);
    }

    public void display() {
        System.out.println("这是影像文件，文件名：" + super.getName());
    }
}

Test

package com.company.demo09composite;

public class Test {
    public static void main(String[] args) {
        Folder f = new Folder("课程");
        Folder f1 = new Folder("一");
        Folder f2 = new Folder("二");
        Folder f3 = new Folder("三");

        f.add(f1);
        f.add(f2);
        f.add(f3);
        
        Text txt1 = new Text("text1.txt");
        Text txt2 = new Text("text2.txt");
        Text txt3 = new Text("text3.txt");

        Image jpg1 = new Image("image1.jpg");
        Image jpg2 = new Image("image2.jpg");
        Image jpg3 = new Image("image3.jpg");

        Video mp41 = new Video("video1.mp4");
        Video mp42 = new Video("video2.mp4");
        Video mp43 = new Video("video3.mp4");

        f1.add(txt1);
        f1.add(jpg1);
        f1.add(mp41);

        f2.add(txt2);
        f2.add(jpg2);
        f2.add(mp42);
        
        f3.add(txt3);
        f3.add(jpg3);
        f3.add(mp43);
    }
}