【不就是Java设计模式吗】代码详解编程中最基础、最重要的设计原则——开闭原则(OCP)

public class One {
    public static void main(String[] args) {
        GraphicEditor graphicEditor = new GraphicEditor();
        graphicEditor.drawShape(new Rectangle());
        graphicEditor.drawShape(new Circle());
        graphicEditor.drawShape(new Triangle());
    }
}
//这是一个用于绘图的类 [使用方]
class GraphicEditor {
    //接收Shape对象，然后根据type，来绘制不同的图形
    public void drawShape(Shape s) {
        if (s.m_type == 1)
            drawRectangle();
        else if (s.m_type == 2)
            drawCircle();
        else if (s.m_type == 3)
            drawTriangle();
    }
    //绘制矩形
    public void drawRectangle() {
        System.out.println(" 绘制矩形 ");
    }
    //绘制圆形
    public void drawCircle() {
        System.out.println(" 绘制圆形 ");
    }
    //绘制三角形
    public void drawTriangle() {
        System.out.println(" 绘制三角形 ");
    }
}
//Shape类，基类
class Shape {
    int m_type;
}
class Rectangle extends Shape {
    public Rectangle() {
        super.m_type = 1;
    }
}
class Circle extends Shape {
    public Circle() {
        super.m_type = 2;
    }
}
//新增画三角形
class Triangle extends Shape {
    public Triangle() {
        super.m_type = 3;
    }
}

public class Two {
    public static void main(String[] args) {
        GraphicEditor1 graphicEditor1 = new GraphicEditor1();
        graphicEditor1.drawShape(new Rectangle1());
        graphicEditor1.drawShape(new Circle1());
        graphicEditor1.drawShape(new Triangle1());
        graphicEditor1.drawShape(new Others());
    }
}
//这是一个用于绘图的类 [使用方]
class GraphicEditor1 {
    public void drawShape(Shape1 shape1){
        shape1.draw();
    }
}
abstract class Shape1 {
    public abstract void draw();
}
class Rectangle1 extends Shape1 {
    public void draw() {
        System.out.println("绘制矩形");
    }
}
class Circle1 extends Shape1 {
    public void draw() {
        System.out.println("绘制圆形");
    }
}
//新增画三角形
class Triangle1 extends Shape1 {
    public void draw() {
        System.out.println("绘制三角形");
    }
}
class Others extends Shape1{
    public void draw() {
        System.out.println("绘制其它图形");
    }
}