写一个基于Java的四则运算

以下是一个简单的基于Java的四则运算实现：

import java.util.Scanner;

public class ArithmeticCalculator {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        double num1, num2, result;
        String operator;

        System.out.println("请输入第一个操作数：");
        num1 = scanner.nextDouble();

        System.out.println("请输入第二个操作数：");
        num2 = scanner.nextDouble();

        System.out.println("请输入运算符（+、-、*、/）：");
        operator = scanner.next();

        switch(operator) {
            case "+":
                result = num1 + num2;
                System.out.println(num1 + " + " + num2 + " = " + result);
                break;
            case "-":
                result = num1 - num2;
                System.out.println(num1 + " - " + num2 + " = " + result);
                break;
            case "*":
                result = num1 * num2;
                System.out.println(num1 + " * " + num2 + " = " + result);
                break;
            case "/":
                if(num2 == 0) {
                    System.out.println("除数不能为0！");
                } else {
                    result = num1 / num2;
                    System.out.println(num1 + " / " + num2 + " = " + result);
                }
                break;
            default:
                System.out.println("无效的运算符！");
        }
    }
}

此代码将提示用户输入两个操作数和运算符，然后根据运算符执行相应的计算并输出结果。注意，此代码未处理输入错误或异常情况。