NBA之工厂模式

Design Pattern:

Factory pattern is one of the most used design patterns in Java. This type of design pattern comes under creational pattern as this pattern provides one of the best ways to create an object. 模式：工厂模式创建对象最多了

故事场景：

public interface Shape {
   void draw();
}
public class Rectangle implements Shape {

   @Override
   public void draw() {
      System.out.println("Inside Rectangle::draw() method.");
   }
}
public class Square implements Shape {

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

工厂

public class ShapeFactory {

   //使用 getShape 方法获取形状类型的对象
   public Shape getShape(String shapeType){
      if(shapeType == null){
         return null;
      }
      if(shapeType.equalsIgnoreCase("RECTANGLE")){
         return new Rectangle();
      } else if(shapeType.equalsIgnoreCase("SQUARE")){
         return new Square();
      }
      return null;
   }
}

实验的开始

   public class FactoryPatternDemo {

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

         //获取 Rectangle 的对象，并调用它的 draw 方法
         Shape shape2 = shapeFactory.getShape("RECTANGLE");

         //调用 Rectangle 的 draw 方法
         shape2.draw();

         //获取 Square 的对象，并调用它的 draw 方法
         Shape shape3 = shapeFactory.getShape("SQUARE");

         //调用 Square 的 draw 方法
         shape3.draw();
      }
   }

结果

Inside Rectangle::draw() method.
Inside Square::draw() method.