用java设计一个计算器窗口

好的，以下是一个简单的计算器窗口的Java代码示例：

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

public class Calculator extends JFrame implements ActionListener {
    private JTextField displayField;
    private JButton[] digitButtons;
    private JButton addButton, subtractButton, multiplyButton, divideButton, equalsButton, clearButton;
    private String displayString = "";
    private double result = 0;
    private String operator = "";

    public Calculator() {
        setTitle("Calculator");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setResizable(false);

        JPanel contentPane = new JPanel();
        contentPane.setLayout(new BorderLayout());

        displayField = new JTextField();
        displayField.setHorizontalAlignment(JTextField.RIGHT);
        displayField.setEditable(false);
        contentPane.add(displayField, BorderLayout.NORTH);

        JPanel buttonPanel = new JPanel();
        buttonPanel.setLayout(new GridLayout(4, 4));

        digitButtons = new JButton[10];
        for (int i = 0; i < digitButtons.length; i++) {
            digitButtons[i] = new JButton("" + i);
            digitButtons[i].addActionListener(this);
        }

        addButton = new JButton("+");
        addButton.addActionListener(this);

        subtractButton = new JButton("-");
        subtractButton.addActionListener(this);

        multiplyButton = new JButton("*");
        multiplyButton.addActionListener(this);

        divideButton = new JButton("/");
        divideButton.addActionListener(this);

        equalsButton = new JButton("=");
        equalsButton.addActionListener(this);

        clearButton = new JButton("C");
        clearButton.addActionListener(this);

        buttonPanel.add(digitButtons[7]);
        buttonPanel.add(digitButtons[8]);
        buttonPanel.add(digitButtons[9]);
        buttonPanel.add(divideButton);
        buttonPanel.add(digitButtons[4]);
        buttonPanel.add(digitButtons[5]);
        buttonPanel.add(digitButtons[6]);
        buttonPanel.add(multiplyButton);
        buttonPanel.add(digitButtons[1]);
        buttonPanel.add(digitButtons[2]);
        buttonPanel.add(digitButtons[3]);
        buttonPanel.add(subtractButton);
        buttonPanel.add(digitButtons[0]);
        buttonPanel.add(clearButton);
        buttonPanel.add(equalsButton);
        buttonPanel.add(addButton);

        contentPane.add(buttonPanel, BorderLayout.CENTER);
        setContentPane(contentPane);
        pack();
        setVisible(true);
    }

    public void actionPerformed(ActionEvent e) {
        String command = e.getActionCommand();
        if (command.charAt(0) >= '0' && command.charAt(0) <= '9' || command.equals(".")) {
            displayString += command;
            displayField.setText(displayString);
        } else if (command.equals("+")) {
            compute();
            operator = "+";
        } else if (command.equals("-")) {
            compute();
            operator = "-";
        } else if (command.equals("*")) {
            compute();
            operator = "*";
        } else if (command.equals("/")) {
            compute();
            operator = "/";
        } else if (command.equals("=")) {
            compute();
            operator = "";
        } else if (command.equals("C")) {
            displayString = "";
            result = 0;
            operator = "";
            displayField.setText("");
        }
    }

    private void compute() {
        if (operator.equals("+")) {
            result += Double.parseDouble(displayString);
        } else if (operator.equals("-")) {
            result -= Double.parseDouble(displayString);
        } else if (operator.equals("*")) {
            result *= Double.parseDouble(displayString);
        } else if (operator.equals("/")) {
            result /= Double.parseDouble(displayString);
        } else {
            result = Double.parseDouble(displayString);
        }
        displayString = "";
        displayField.setText("" + result);
    }

    public static void main(String[] args) {
        Calculator calculator = new Calculator();
    }
}

这段代码创建了一个简单的计算器窗口，其中包含一个显示器文本框和一组数字和操作符按钮。用户可以通过按下这些按钮来输入数字和操作符，并通过按下“=”按钮来计算结果。计算器还包含一个“C”按钮，用于清除当前输入。