创建型模式之简单工厂模式（绘制图形）

痛定思痛。 2022-08-09 18:55 325阅读 0赞

题目：

1．   使用简单工厂模式设计一个可以创建不同几何形状(Shape)的绘图工具类，如可创建圆形(Circle)、矩形(Rectangle)、和三角形(Triangle)对象，每个几何图形均具有绘制和擦除两个方法，要求在绘制不支持的几何图形时，抛出一个异常(UnsupportedShapeException)，或实现一个简单计算器，绘制类图并编程实现。

类图

![20151104152325069][]

package cn.factory1;
    
    public class Circle implements Shape {
    	public void init() {
    		System.out.println("创建圆形。。。");
    	}
    }

package cn.factory1;
    
    public class Rectangle implements Shape {
    	public void init() {
    		System.out.println("创建长方形。。。");
    	}
    }

package cn.factory1;
    
    public interface Shape {
    	public void init();
    }

package cn.factory1;
    
    public class ShapeFactory {
    	public static Shape initShape(String name) throws Exception {
    		if(name.equalsIgnoreCase("Circle")){
    			System.out.println("图形工厂生产圆形！");
    			return new Circle();
    		}
    		else if(name.equalsIgnoreCase("Triangle")) {
    			System.out.println("图形工厂生产三角形！");
    			return new Triangle();
    		}
    		else if(name.equalsIgnoreCase("Rectangle")) {
    			System.out.println("图形工厂生产长方形！");
    			return new Rectangle();
    		}
    		else {
    			throw new Exception("对不起，暂不能生产该种图形！");
    		}
    	}
    	public static void deleteShape(String name) throws Exception {
    		if(name.equalsIgnoreCase("Circle")){
    			System.out.println("已销毁圆形！");
    		}
    		else if(name.equalsIgnoreCase("Triangle")) {
    			System.out.println("已销毁三角形！");
    		}
    		else if(name.equalsIgnoreCase("Rectangle")) {
    			System.out.println("已销毁长方形！");
    		}
    		else {
    			throw new Exception("对不起，图形工厂中没有该种图形！");
    		}
    	}	
    }

package cn.factory1;
    
    public class SimpleFac {
    	public static void main(String[] args) {
    		try {
    			Shape shape;
    			shape = ShapeFactory.initShape("Circle");
    			shape.init();
    			//shape = ShapeFactory.initShape("Triangle");
    			//shape.init();
    			//shape = ShapeFactory.initShape("Rectangle");
    			//shape.init();
    			//shape = ShapeFactory.initShape("app");
    			//shape.init();
    		}
    		catch(Exception e) {
    			System.out.println(e.getMessage());
    		}
    	}
    }

package cn.factory1;
    
    public class Triangle implements Shape {
    	public void init() {
    		System.out.println("创建三角形。。。");
    	}
    }

运行效果图

![20151104152811072][]

注意：这个程序是在SimpleFac类中运行

[20151104152325069]: /images/20220731/474e44749a45404693d9983af02fbb6d.png
[20151104152811072]: /images/20220731/1f96b76a622c473b8e51723a2b86fc4a.png