java窗体简易计算器

好的，以下是一个简单的Java窗体计算器程序，支持加、减、乘、除四则运算：

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

public class Calculator extends JFrame implements ActionListener {
    private JTextField num1Field, num2Field, resultField;
    private JButton addButton, subButton, mulButton, divButton;

    public Calculator() {
        setTitle("简易计算器");
        setSize(300, 200);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLocationRelativeTo(null);

        // 创建面板
        JPanel panel = new JPanel(new GridLayout(4, 2));

        // 创建组件
        JLabel num1Label = new JLabel("第一个数：");
        num1Field = new JTextField(10);
        JLabel num2Label = new JLabel("第二个数：");
        num2Field = new JTextField(10);
        JLabel resultLabel = new JLabel("结果：");
        resultField = new JTextField(10);
        resultField.setEditable(false);
        addButton = new JButton("+");
        subButton = new JButton("-");
        mulButton = new JButton("*");
        divButton = new JButton("/");

        // 添加组件到面板
        panel.add(num1Label);
        panel.add(num1Field);
        panel.add(num2Label);
        panel.add(num2Field);
        panel.add(resultLabel);
        panel.add(resultField);
        panel.add(addButton);
        panel.add(subButton);
        panel.add(mulButton);
        panel.add(divButton);

        // 添加面板到窗体
        add(panel);

        // 添加事件监听器
        addButton.addActionListener(this);
        subButton.addActionListener(this);
        mulButton.addActionListener(this);
        divButton.addActionListener(this);

        setVisible(true);
    }

    @Override
    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) {
            if(num2 == 0) {
                JOptionPane.showMessageDialog(this, "除数不能为0！", "错误", JOptionPane.ERROR_MESSAGE);
                return;
            }
            result = num1 / num2;
        }

        resultField.setText(String.valueOf(result));
    }

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

你可以根据需要对代码进行调整和修改，比如添加更多的运算符、增加输入检查等。