public class Rectangle{ int length; int width; public void getArea(){ System.out.println(length * width); } public void getper(){ System.out.println((length + width)*2); } public void showAll(){ System.out.println(length * width); System.out.println("长是" + length); System.out.println("宽是" + width); System.out.println("面积是"); getArea(); System.out.println("周长是"); getPer(); } } import java.util.Scanner; public class Demon3.{ public staitc void main(String[] args){ Rectangle mhl = new Rectangle(); //连接 Scanner p=new Scanner(System.in) //控制台输入 System.out.print("请输入长"); mhl.length = input.nextInt(); System.out.print("请输入宽:"); mhl.with=input.nextInt(); mhl.showAll(); } }