设计模式之------工厂模式

工厂模式简介内容参考易百教程

1、创建接口
2、创建实现接口的具体类，实现接口并重写接口中的方法。（对于抽象类，可以不用实现接口中的所有方法，可以又他的子类实现。普通的实现类，必须实现接口中的所有方法。）
3、创建工厂类
4、创建演示类，通过工厂类获取对象

流程如下：演示类中初始化工厂类，通过工厂类创建对象，对象实现了接口中的方法。

1、创建Shape接口
Shape.java

public interface Shape {
    void draw();
}

2.创建实现接口的具体类
Rectangle.java

public class Rectangle implements Shape {
    @Override
    public void draw() {
        System.out.print(" Rectangle --- implements Shape");
    }
}

Square.java

public class Square implements Shape {

    @Override
    public void draw() {
        System.out.print("Square --- implements Shape");
    }
}

Circle.java

public class Circle implements Shape {

    @Override
    public void draw() {
        System.out.print(" Circle --- implements Shape");
    }
}

3、创建工厂类
ShapeFactory.java

public class ShapeFactory {

    public Shape getShape(String shapetype){

        if(shapetype == null){
            System.out.println("shape type is null");
            return null;
        }
        
        if(shapetype.equalsIgnoreCase("Rectangle")){
            System.out.println("Rectangle   ---  is shape type");
            return  new Rectangle();
        }else if (shapetype.equalsIgnoreCase("Square")){
            System.out.println("Square  ---------  is shape type");
            return new Square();
        }else if(shapetype.equalsIgnoreCase("Circle")){
            System.out.println("Circle  is --- shape type");
            return new Circle();
        }else {
            System.out.println("not found this method");
        }
        return  null;
    }
}

4、创建创建演示类，通过工厂类创建对象
FactoryPatternDemo.java

public class FactoryPatternDemo {
    
    public static void main(String[] args) {

        ShapeFactory shapeFactory = new ShapeFactory();

        Shape shape1 = shapeFactory.getShape("Rectangle");
        shape1.draw();

        System.out.println("1-------------------------------2");

        Shape shape2 = shapeFactory.getShape("Circle");
        shape2.draw();

        System.out.println("2-------------------------------2");

        Shape shape3 = shapeFactory.getShape("Square");
        shape3.draw();

    }
}

结果如下：

Rectangle   ---  is shape type
Rectangle --- implements Shape1-------------------------------2
Circle  is --- shape type
Circle --- implements Shape2-------------------------------2
Square  ---------  is shape type
Square --- implements Shape
Process finished with exit code 0

参考链接：Java工厂设计模式