用Java swing写一个可以运行计算器

以下是一个简单的Java Swing计算器示例：

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

public class Calculator extends JFrame implements ActionListener {

    private JTextField textField;
    private JButton button0, button1, button2, button3, button4, button5, button6, button7, button8, button9;
    private JButton buttonAdd, buttonSubtract, buttonMultiply, buttonDivide, buttonEqual, buttonClear;

    private double num1 = 0, num2 = 0;
    private char operation = ' ';

    public Calculator() {
        setTitle("Calculator");
        setSize(300, 400);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        textField = new JTextField();
        textField.setEditable(false);
        textField.setPreferredSize(new Dimension(280, 50));
        textField.setHorizontalAlignment(JTextField.RIGHT);

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

        button7 = new JButton("7");
        button8 = new JButton("8");
        button9 = new JButton("9");
        buttonAdd = new JButton("+");

        button4 = new JButton("4");
        button5 = new JButton("5");
        button6 = new JButton("6");
        buttonSubtract = new JButton("-");

        button1 = new JButton("1");
        button2 = new JButton("2");
        button3 = new JButton("3");
        buttonMultiply = new JButton("*");

        button0 = new JButton("0");
        buttonClear = new JButton("C");
        buttonEqual = new JButton("=");
        buttonDivide = new JButton("/");

        button7.addActionListener(this);
        button8.addActionListener(this);
        button9.addActionListener(this);
        buttonAdd.addActionListener(this);

        button4.addActionListener(this);
        button5.addActionListener(this);
        button6.addActionListener(this);
        buttonSubtract.addActionListener(this);

        button1.addActionListener(this);
        button2.addActionListener(this);
        button3.addActionListener(this);
        buttonMultiply.addActionListener(this);

        button0.addActionListener(this);
        buttonClear.addActionListener(this);
        buttonEqual.addActionListener(this);
        buttonDivide.addActionListener(this);

        buttonPanel.add(button7);
        buttonPanel.add(button8);
        buttonPanel.add(button9);
        buttonPanel.add(buttonAdd);

        buttonPanel.add(button4);
        buttonPanel.add(button5);
        buttonPanel.add(button6);
        buttonPanel.add(buttonSubtract);

        buttonPanel.add(button1);
        buttonPanel.add(button2);
        buttonPanel.add(button3);
        buttonPanel.add(buttonMultiply);

        buttonPanel.add(button0);
        buttonPanel.add(buttonClear);
        buttonPanel.add(buttonEqual);
        buttonPanel.add(buttonDivide);

        add(textField, BorderLayout.NORTH);
        add(buttonPanel, BorderLayout.CENTER);
        setVisible(true);
    }

    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == button0) {
            textField.setText(textField.getText() + "0");
        } else if (e.getSource() == button1) {
            textField.setText(textField.getText() + "1");
        } else if (e.getSource() == button2) {
            textField.setText(textField.getText() + "2");
        } else if (e.getSource() == button3) {
            textField.setText(textField.getText() + "3");
        } else if (e.getSource() == button4) {
            textField.setText(textField.getText() + "4");
        } else if (e.getSource() == button5) {
            textField.setText(textField.getText() + "5");
        } else if (e.getSource() == button6) {
            textField.setText(textField.getText() + "6");
        } else if (e.getSource() == button7) {
            textField.setText(textField.getText() + "7");
        } else if (e.getSource() == button8) {
            textField.setText(textField.getText() + "8");
        } else if (e.getSource() == button9) {
            textField.setText(textField.getText() + "9");
        } else if (e.getSource() == buttonClear) {
            textField.setText("");
            num1 = 0;
            num2 = 0;
            operation = ' ';
        } else if (e.getSource() == buttonAdd) {
            num1 = Double.parseDouble(textField.getText());
            operation = '+';
            textField.setText("");
        } else if (e.getSource() == buttonSubtract) {
            num1 = Double.parseDouble(textField.getText());
            operation = '-';
            textField.setText("");
        } else if (e.getSource() == buttonMultiply) {
            num1 = Double.parseDouble(textField.getText());
            operation = '*';
            textField.setText("");
        } else if (e.getSource() == buttonDivide) {
            num1 = Double.parseDouble(textField.getText());
            operation = '/';
            textField.setText("");
        } else if (e.getSource() == buttonEqual) {
            num2 = Double.parseDouble(textField.getText());
            if (operation == '+') {
                textField.setText(String.valueOf(num1 + num2));
            } else if (operation == '-') {
                textField.setText(String.valueOf(num1 - num2));
            } else if (operation == '*') {
                textField.setText(String.valueOf(num1 * num2));
            } else if (operation == '/') {
                textField.setText(String.valueOf(num1 / num2));
            }
            num1 = 0;
            num2 = 0;
            operation = ' ';
        }
    }

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

这个示例程序创建了一个简单的计算器，可以进行加、减、乘、除四则运算。用户可以通过单击按钮输入数字，通过单击运算符按钮执行相应的运算，最终结果将显示在文本框中。