Java学习---计算器（简易）

小练习：写一个计算器，要求实现加减乘除功能，并且能循环接受新的数据。

以下是我的代码：

import java.util.Scanner;

public class Demo1 {
    public static void main(String[] args) {
        Demo1 demo1 = new Demo1();
        for (int i = 0; i < 1000; i++) {
            System.out.println("您需要做什么计算？加法、减法、乘法、除法。");
            System.out.println("完成请输入退出");
            Scanner scanner = new Scanner(System.in);
            String need = scanner.nextLine();
            if(need.equals("加法")){
                double x = scanner.nextDouble();
                double y = scanner.nextDouble();
                demo1.add(x, y);
            }else if (need.equals("减法")) {
                double x = scanner.nextDouble();
                double y = scanner.nextDouble();
                demo1.sub(x, y);
            }else if (need.equals("乘法")) {
                double x = scanner.nextDouble();
                double y = scanner.nextDouble();
                demo1.multi(x, y);
            }else if (need.equals("减法")) {
                double x = scanner.nextDouble();
                double y = scanner.nextDouble();
                demo1.div(x, y);
            } else if (need.equals("退出")) {
                break;
            }
        }
    }
    public void add(double a, double b){
        double sum = 0;
        sum = a + b;
        System.out.println(a + "+" + b + "=" + sum);
    }
    public void sub(double a, double b){
        double sum = 0;
        sum = a - b;
        System.out.println(a + "-" + b + "=" + sum);
    }
    public void multi(double a, double b){
        double sum = 0;
        sum = a * b;
        System.out.println(a + "*" + b + "=" + sum);
    }
    public void div(double a, double b){
        double sum = 0;
        sum = a / b;
        System.out.println(a + "/" + b + "=" + sum);
    }
}

还请各位大神亮出你们的代码，我的代码好像太啰嗦了。