通过java swing编写一个计算器

好的，下面是一个简单的 Java Swing 计算器实现，包括加减乘除四则运算：

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

public class Calculator extends JFrame implements ActionListener {

    private static final long serialVersionUID = 1L;
    private JTextField num1Field, num2Field, resultField;
    private JButton addButton, subButton, mulButton, divButton;

    public Calculator() {
        super("Calculator");
        setLayout(new GridLayout(4, 2));

        JLabel num1Label = new JLabel("Number 1:");
        num1Field = new JTextField(10);

        JLabel num2Label = new JLabel("Number 2:");
        num2Field = new JTextField(10);

        JLabel resultLabel = new JLabel("Result:");
        resultField = new JTextField(10);
        resultField.setEditable(false);

        addButton = new JButton("+");
        subButton = new JButton("-");
        mulButton = new JButton("*");
        divButton = new JButton("/");

        addButton.addActionListener(this);
        subButton.addActionListener(this);
        mulButton.addActionListener(this);
        divButton.addActionListener(this);

        add(num1Label);
        add(num1Field);
        add(num2Label);
        add(num2Field);
        add(resultLabel);
        add(resultField);
        add(addButton);
        add(subButton);
        add(mulButton);
        add(divButton);

        setSize(300, 150);
        setVisible(true);
    }

    public void actionPerformed(ActionEvent e) {
        double num1 = Double.parseDouble(num1Field.getText());
        double num2 = Double.parseDouble(num2Field.getText());
        double result = 0;

        if (e.getSource() == addButton) {
            result = num1 + num2;
        } else if (e.getSource() == subButton) {
            result = num1 - num2;
        } else if (e.getSource() == mulButton) {
            result = num1 * num2;
        } else if (e.getSource() == divButton) {
            result = num1 / num2;
        }

        resultField.setText(Double.toString(result));
    }

    public static void main(String[] args) {
        Calculator calc = new Calculator();
        calc.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

}

该计算器界面包含两个文本框和四个按钮，用户可以输入两个数字并选择加减乘除四个运算符。结果将显示在第三个文本框中。运算过程在 `actionPerformed` 方法中实现。