用java语言写一个能在eclipse环境中运行的代码，代码内容为写一个窗口，实现计算器的加减乘除功能

在Java中，我们可以创建一个简单的图形用户界面（GUI）计算器来实现基本的加减乘除功能。这里我会提供一个基础的Swing框架示例，它可以在Eclipse环境下运行：

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class SimpleCalculator extends JFrame {
    private JTextField display;
    private JButton[] buttons = new JButton[4]; // 数字0-9
    private JButton operatorButtons = new JButton[]{"+", "-", "*", "/"}; // 运算符按钮
    private String currentDisplay = "0";

    public SimpleCalculator() {
        setTitle("简单计算器");
        setSize(300, 350);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JPanel panel = new JPanel();
        panel.setLayout(new GridLayout(5, 6)); // 5行6列布局

        for (int i = 0; i < 10; i++) { // 数字按钮
            buttons[i] = new JButton(String.valueOf(i));
            buttons[i].addActionListener(e -> doOperation());
            panel.add(buttons[i]);
        }

        for (String op : operatorButtons) { // 运算符按钮
            JButton button = new JButton(op);
            button.addActionListener(e -> {
                if (!currentDisplay.isEmpty()) {
                    double num1 = Double.parseDouble(currentDisplay);
                    currentDisplay = "";
                    performOperation(num1, op);
                }
            });
            panel.add(button);
        }

        display = new JTextField(15);
        display.setEditable(false);
        display.setHorizontalAlignment(JTextField.CENTER);
        panel.add(display);

        add(panel);
        setVisible(true);
    }

    private void doOperation() {
        String newNumber = display.getText() + buttons[(int) event.getSource().getActionCommand()].getText();
        currentDisplay += newNumber;
        display.setText(currentDisplay);
    }

    private void performOperation(double num1, String operator) {
        try {
            double result = 0;
            switch (operator) {
                case "+":
                    result = num1 + Double.parseDouble(currentDisplay);
                    break;
                case "-":
                    result = num1 - Double.parseDouble(currentDisplay);
                    break;
                case "*":
                    result = num1 * Double.parseDouble(currentDisplay);
                    break;
                case "/":
                    result = num1 / Double.parseDouble(currentDisplay);
                    break;
                default:
                    JOptionPane.showMessageDialog(this, "无效的运算符");
                    return;
            }
            currentDisplay = String.format("%.2f", result);
        } catch (NumberFormatException e) {
            JOptionPane.showMessageDialog(this, "请输入数字");
            currentDisplay = "0";
        }
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(() -> new SimpleCalculator());
    }
}