【Java】工厂模式

最新推荐文章于 2025-06-16 14:27:41 发布

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#工厂模式

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模式思想

约定一个接口
定义实现接口的实体类
定义用来获取实体类的工厂类
调用工厂类

代码实现

约定接口

package factory;

public interface Shape {

    void draw();
}

实现接口的实体类

Circle.java

package factory;

public class Circle implements Shape {

    public void draw() {
        System.out.println("Inside Circle::draw() method.");
    }
}

Rectangle.java

package factory;

public class Rectangle implements Shape {

    public void draw() {
        System.out.println("Inside Rectangle::draw() method.");
    }
}

Square.java

package factory;

public class Square implements Shape {

    public void draw() {
        System.out.println("Inside Square::draw() method.");
    }
}

定义工厂类

package factory;

public class ShapeFactory {

    public Shape getShape(String shapeType) {
        if (shapeType == null) {
            return null;
        }

        if (shapeType.equalsIgnoreCase("CIRCLE")) {
            return new Circle();
        } else if (shapeType.equalsIgnoreCase("RECTANGLE")) {
            return new Rectangle();
        } else if (shapeType.equalsIgnoreCase("SQUARE")) {
            return new Square();
        }

        return null;
    }
}

调用工厂类

import factory.Shape;
import factory.ShapeFactory;

public class FactoryDemo {

    public static void main(String[] args) {
        ShapeFactory shapeFactory = new ShapeFactory();

        Shape shapeCircle = shapeFactory.getShape("Circle");
        shapeCircle.draw();

        Shape shapeRectangle = shapeFactory.getShape("Rectangle");
        shapeRectangle.draw();

        Shape shapeSquare = shapeFactory.getShape("Square");
        shapeSquare.draw();
    }
}