设计模式系列：外观模式

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概念

外观模式用于简化系统中一个或者多个复杂的类。外观模式相当直接，容易理解。它提供了一个统一的接口，用来访问子系统中的一群接口。外观定义了一个
高层接口，让子同更容易使用。

实现

图片

  • 类图：

图片

MyOneDay:

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package com.littlehui.design.facade;

/**
 * Created by littlehui on 2018/1/16.
 * 我的一天
 */
public class MyOneDay {

    private Morning morning;

    private Road road;

    private Back back;

    private Office office;

    private Rest rest;

    public MyOneDay(Morning morning, Office office, Back back, Road road, Rest rest) {
        this.morning = morning;
        this.office = office;
        this.back = back;
        this.road = road;
        this.rest = rest;
    }

    /**
     * 在家起床
     */
    public void morning() {
        morning.morningStepA();
        morning.morningStepB();
        morning.moringStepC();
    }

    /**
     * 去公司
     */
    public void goToOffice() {
        road.onLoadA();
        road.onLoadB();
        road.onLoadC();
        road.onLoadE();
    }

    /**
     * 工作，coding
     */
    public void work() {
        office.officeA();
        office.officeB();
        office.officeC();
    }

    public void backToHome() {
        back.backStepA();
        back.backStepB();
        back.backStepC();
        back.backStepD();
    }

    public void rest() {
        rest.restA();
        rest.restB();
        rest.restC();
        rest.restD();
    }

    public void myWholeDay() {
        morning();
        goToOffice();
        work();
        backToHome();
        rest();
    }
}

Morning:

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package com.littlehui.design.facade;

/**
 * Created by littlehui on 2018/1/16.
 */
public class Morning {

    public void morningStepA() {
        System.out.println("起床刷牙洗脸");
    }

    public void morningStepB() {
        System.out.println("吃早饭");
    }

    public void moringStepC() {
        System.out.println("带上背包出门");
    }
}

Office:

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package com.littlehui.design.facade;

/**
 * Created by littlehui on 2018/1/16.
 */
public class Office {

    public void officeA() {
        System.out.println("放下背包");
    }

    public void officeB() {
        System.out.println("去除电脑开机");
    }

    public void officeC() {
        System.out.println("打开IDEA 愉快地codeing");
    }
}

Client:

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package com.littlehui.design.facade;

/**
 * Created by littlehui on 2018/1/16.
 */
public class Client {
    public static void main(String[] args) {
        MyOneDay myOneDay = new MyOneDay(new Morning(), new Office(), new Back(), new Road(), new Rest());
        myOneDay.myWholeDay();
    }
}

以上其他类略：
详情github链接： 设计模式

场景

总结

外观模式体现了设计模式中 最少知识原则。不让太多的类耦合在一起。