用Java写一个计算器界面

在Java中编写一个简单的命令行计算器界面，我们可以使用控制台输入输出来模拟。首先，创建一个Calculator类，包含加、减、乘、除等基本运算方法。下面是一个简化的示例：

import java.util.Scanner;

class Calculator {
    public int add(int num1, int num2) {
        return num1 + num2;
    }

    public int subtract(int num1, int num2) {
        return num1 - num2;
    }

    public int multiply(int num1, int num2) {
        return num1 * num2;
    }

    public double divide(int num1, int num2) throws ArithmeticException {
        if (num2 != 0) {
            return (double) num1 / num2;
        } else {
            throw new ArithmeticException("Cannot divide by zero");
        }
    }
}

public class CalculatorInterface {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        Calculator calculator = new Calculator();
        System.out.println("Simple Calculator:");
        while (true) {
            System.out.print("Enter an operation (+, -, *, /), or 'quit' to exit: ");
            String op = scanner.nextLine();
            if (op.equalsIgnoreCase("quit")) {
                break;
            }
            System.out.print("Enter two numbers: ");
            int num1 = scanner.nextInt();
            int num2 = scanner.nextInt();
            
            try {
                switch (op) {
                    case "+":
                        System.out.println(num1 + " + " + num2 + " = " + calculator.add(num1, num2));
                        break;
                    case "-":
                        System.out.println(num1 + " - " + num2 + " = " + calculator.subtract(num1, num2));
                        break;
                    case "*":
                        System.out.println(num1 + " * " + num2 + " = " + calculator.multiply(num1, num2));
                        break;
                    case "/":
                        System.out.println(num1 + " / " + num2 + " = " + calculator.divide(num1, num2));
                        break;
                    default:
                        System.out.println("Invalid operation");
                }
            } catch (ArithmeticException e) {
                System.out.println(e.getMessage());
            }
        }
        scanner.close();
    }
}

在这个例子中，用户通过控制台输入操作符和数字，程序会调用Calculator类的方法进行计算。