有一类实体是形状（Shape）包含矩形（Rectangle）、圆形（Circle）等，请使用工厂方法模式（FactoryMethod）实现该要求。 1.画出类结构图 2.采用java语言实现该工厂方法模式，并写测试程序main（）进行测试

这是类结构图：

+--------------+        +------------+
|     Shape    |        | ShapeFactory |
+--------------+        +------------+
| draw()       |<-------| createShape |
+--------------+        +------------+
                             /|\
                              |
           +------------+-----+------------+
           |                        |               
     +------------+         +------------+
     |  Rectangle |         |   Circle   |
     +------------+         +------------+

这是Java代码实现：

首先是Shape接口：

public interface Shape {
    void draw();
}

然后是Rectangle类：

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

接着是Circle类：

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

现在是ShapeFactory类：

public class ShapeFactory {
    public Shape createShape(String type) {
        if (type.equalsIgnoreCase("Rectangle")) {
            return new Rectangle();
        } else if (type.equalsIgnoreCase("Circle")) {
            return new Circle();
        } else {
            return null;
        }
    }
}

最后是测试程序main()：

public class FactoryMethodTest {
    public static void main(String[] args) {
        ShapeFactory factory = new ShapeFactory();

        Shape shape1 = factory.createShape("Rectangle");
        shape1.draw();

        Shape shape2 = factory.createShape("Circle");
        shape2.draw();
    }
}

输出结果：

Drawing rectangle
Drawing circle