里氏代换原则

package com.jmj.principles.dmeo2.after;/*** 四边形接口*/
public interface Quadrilateral {double getLength();double getWidth();}

package com.jmj.principles.dmeo2.after;/*** 长方形类*/
public class Rectangle implements Quadrilateral{private double length;private double width;public double getWidth() {return width;}public void setWidth(double width) {this.width = width;}public double getLength() {return length;}public void setLength(double length) {this.length = length;}
}

package com.jmj.principles.dmeo2.after;public class RectangleDemo {public static void main(String[] args) {Rectangle rectangle = new Rectangle();rectangle.setLength(20);rectangle.setWidth(10);resize(rectangle);printLengthAndWidth(rectangle);}//扩宽方法public static void  resize(Rectangle rectangle){//宽如果比长小，进行扩宽的操作while (rectangle.getWidth()<=rectangle.getLength()){rectangle.setWidth(rectangle.getWidth()+1);}}public static void printLengthAndWidth(Rectangle rectangle){System.out.println(rectangle.getLength());System.out.println(rectangle.getWidth());}}

package com.jmj.principles.dmeo2.after;import com.jmj.principles.dmeo2.before.Rectangle;/*** 正方形*/
public class Square implements Quadrilateral {private double side;public double getSide() {return side;}public void setSide(double side) {this.side = side;}@Overridepublic double getLength() {return side;}@Overridepublic double getWidth() {return side;}
}