Facade模式的定义: 外观模式隐藏系统的复杂性，并向客户端提供了一个客户端可以访问系统的接口，它向现有的系统添加一个接口，来隐藏系统的复杂性。

我们将创建一个 Shape 接口和实现了 Shape 接口的实体类。下一步是定义一个外观类 ShapeMaker。ShapeMaker 类使用实体类来代表用户对这些类的调用

Shape:形状接口Circle:Shape实现类，圆Rectangle:Shape实现类，矩形Square:Shape实现类，正方形ShapeMaker:形状创造类复制代码

Shape接口代码

public interface Shape {    void draw();}复制代码

Circle类代码

public class Circle implements Shape {    @Override    public void draw() {        System.out.println("circle");    }}复制代码

Rectangle类代码

public class Rectangle implements Shape {    @Override    public void draw() {        System.out.println("rectangle");    }}复制代码

Square类代码

public class Square implements Shape {    @Override    public void draw() {        System.out.println("square");    }}复制代码

ShapeMaker类代码

public class ShapeMaker {    private Circle circle;    private Rectangle rectangle;    private Square square;    public ShapeMaker() {        this.circle = new Circle();        this.rectangle = new Rectangle();        this.square = new Square();    }    public void drawCircle() {        circle.draw();    }    public void drawRectangle() {        rectangle.draw();    }    public void drawSquare() {        square.draw();    }}复制代码

ShapeMaker使用

ShapeMaker maker = new ShapeMaker();        maker.drawCircle();        maker.drawRectangle();        maker.drawSquare();复制代码