设计模式实现：工厂方法与抽象工厂的应用实例

原创你的名字 2024-12-12 13:33 7阅读 0赞

工厂方法（Factory Method）和抽象工厂（Abstract Factory）是面向对象编程中两种常用的工厂模式。

**工厂方法（Factory Method）实例：**

1. **简单工厂模式：**
   ```java
   // 工厂接口
   public interface ShapeFactory {
       Shape createShape(String shapeType);
   }

// 简单工厂实现
   class SimpleShapeFactory implements ShapeFactory {
       @Override
       public Shape createShape(String shapeType) {
           if (shapeType.equalsIgnoreCase("Circle")) {
               return new Circle();
           } else if (shapeType.equalsIgnoreCase("Rectangle")) {
               return new Rectangle();
           }
           return null; //非法形状类型
       }
   }

// 使用工厂创建形状实例
   public class ShapeDemo {
       public static void main(String[] args) {
           ShapeFactory shapeFactory = new SimpleShapeFactory();

Shape circle = shapeFactory.createShape("Circle");
           if (circle != null) {
               System.out.println("Created Circle: " + circle);
           }

Shape rectangle = shapeFactory.createShape("Rectangle");
           if (rectangle != null) {
               System.out.println("Created Rectangle: " + rectangle);
           }
       }
   ```
2. **工厂方法的实现，可能在一个具体的类中：**
```java
// 具体工厂类
class CircleFactory extends ShapeFactory {
    @Override
    public Shape createShape(String shapeType) {
        if (shapeType.equalsIgnoreCase("Circle")) {
            return new Circle();
        }
        return null; //非法形状类型
    }
}

// 使用工厂创建具体形状实例
public class ShapeDemo {
    public static void main(String[] args) {
        ShapeFactory shapeFactory = new CircleFactory();

Shape circle = shapeFactory.createShape("Circle");
        if (circle != null) {
            System.out.println("Created Circle: " + circle);
        }

// 如果需要创建矩形，可以使用相同工厂
        Shape rectangle = shapeFactory.createShape("Rectangle");
        if (rectangle != null) {
            System.out.println("Created Rectangle: " + rectangle);
        }
    }
}
```

**抽象工厂（Abstract Factory）实例：**

1. **多个具体工厂类的集合：**
```java
// 抽象工厂接口
public interface ShapeFactoryInterface {
    Shape createShape(String shapeType);
}

// 抽象工厂实现
abstract class AbstractShapeFactory implements ShapeFactoryInterface {
    @Override
    public Shape createShape(String shapeType) {
        // 实现不同形状的具体创建逻辑
        if (shapeType.equalsIgnoreCase("Circle")) {
            return new Circle();
        } else if (shapeType.equalsIgnoreCase("Rectangle")) {
            return new Rectangle();
        }
        return null; //非法形状类型
    }
}
```
2. **使用抽象工厂创建具体形状实例：**
```java
// 使用抽象工厂创建具体形状实例
public class ShapeDemo {
    public static void main(String[] args) {
        ShapeFactoryInterface shapeFactory = new AbstractShapeFactory();

Shape circle = shapeFactory.createShape("Circle");
        if (circle != null) {
            System.out.println("Created Circle: " + circle);
        }

// 创建矩形形状，逻辑同上
        Shape rectangle = shapeFactory.createShape("Rectangle");
        if (rectangle != null) {
            System.out.println("Created Rectangle: " + rectangle);
        }
    }
}
```
这样就实现了工厂方法和抽象工厂的设计模式。