用java语言帮我写一个简易计算器的代码

当然可以，下面是一个简单的Java控制台版计算器程序示例，它实现了加、减、乘、除的功能：

import java.util.Scanner;

public class SimpleCalculator {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        
        System.out.println("请输入第一个数字:");
        double num1 = scanner.nextDouble();
        System.out.println("请输入操作符(+, -, *, /):");
        char operator = scanner.next().charAt(0);
        System.out.println("请输入第二个数字:");
        double num2 = scanner.nextDouble();

        switch (operator) {
            case '+':
                double result = add(num1, num2);
                System.out.printf("%.2f + %.2f = %.2f\n", num1, num2, result);
                break;
            case '-':
                result = subtract(num1, num2);
                System.out.printf("%.2f - %.2f = %.2f\n", num1, num2, result);
                break;
            case '*':
                result = multiply(num1, num2);
                System.out.printf("%.2f * %.2f = %.2f\n", num1, num2, result);
                break;
            case '/':
                if (num2 != 0) {
                    result = divide(num1, num2);
                    System.out.printf("%.2f / %.2f = %.2f\n", num1, num2, result);
                } else {
                    System.out.println("错误：除数不能为零!");
                }
                break;
            default:
                System.out.println("错误：无效的操作符!");
                break;
        }

        scanner.close();
    }

    // 加法函数
    private static double add(double a, double b) {
        return a + b;
    }

    // 减法函数
    private static double subtract(double a, double b) {
        return a - b;
    }

    // 乘法函数
    private static double multiply(double a, double b) {
        return a * b;
    }

    // 除法函数
    private static double divide(double a, double b) {
        return a / b;
    }
}