外观模式(Facade)

public class CPU {

    public void startup(){
        System.out.println("启动CPU");
    }
}

public class Memory {

    public void startup(){
        System.out.println("启动内存");
    }
}

public class Disk {

    public void startup(){
        System.out.println("启动硬盘");
    }
}

//facade
public class Computer {

    CPU cpu;
    Memory memory;
    Disk disk;

    public Computer(){
        cpu = new CPU();
        memory = new Memory();
        disk = new Disk();
    }

    public void start(){
        cpu.startup();
        memory.startup();
        disk.startup();
    }
}

public static void main(String[] args) {
        Computer computer = new Computer();
        //启动computer是个很复杂的过程,我们并不需要知道其启动各个子系统的加载过程
        //只需要调用computer为各个子系统提供统一的一个接口start()就可以启动computer了
        computer.start();
    }

package com.qbz.test;

class Frame {
    public void create() {
        System.out.println("组装骨架");
    }
}

class Engine {
    public void create() {
        System.out.println("组装引擎");
    }
}

class Wheel {
    public void create() {
        System.out.println("组装轮子");
    }
}

class Controller {
    private Frame frame;
    private Engine engine;
    private Wheel wheel;

    public Controller() {
        frame = new Frame();
        engine = new Engine();
        wheel = new Wheel();
    }

    public void build() {
        // 汽车组装过程
        frame.create();
        engine.create();
        wheel.create();
        System.out.println("汽车组装完成");
    }
}

public class Main {

    public static void main(String[] args) {
        Controller controller = new Controller();
        // 操作员按生产按钮开始组装汽车
        controller.build();
    }

}

组装骨架
组装引擎
组装轮子
汽车组装完成