java实现计算器页面

以下是一个简单的Java计算器页面实现示例：

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

public class Calculator {
    JFrame frame;
    JTextField textField;

    double num1, num2, result;
    char operator;

    public Calculator() {
        frame = new JFrame("Calculator");
        frame.getContentPane().setLayout(new BorderLayout());

        textField = new JTextField();
        textField.setHorizontalAlignment(JTextField.RIGHT);
        textField.setEditable(false);
        frame.getContentPane().add(textField, BorderLayout.NORTH);

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

        addButton(buttonPanel, "7");
        addButton(buttonPanel, "8");
        addButton(buttonPanel, "9");
        addButton(buttonPanel, "/");
        addButton(buttonPanel, "4");
        addButton(buttonPanel, "5");
        addButton(buttonPanel, "6");
        addButton(buttonPanel, "*");
        addButton(buttonPanel, "1");
        addButton(buttonPanel, "2");
        addButton(buttonPanel, "3");
        addButton(buttonPanel, "-");
        addButton(buttonPanel, "0");
        addButton(buttonPanel, ".");
        addButton(buttonPanel, "=");
        addButton(buttonPanel, "+");

        frame.getContentPane().add(buttonPanel, BorderLayout.CENTER);

        frame.pack();
        frame.setVisible(true);
    }

    private void addButton(Container container, String text) {
        JButton button = new JButton(text);
        button.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                switch (text) {
                    case "/":
                    case "*":
                    case "-":
                    case "+":
                        operator = text.charAt(0);
                        num1 = Double.parseDouble(textField.getText());
                        textField.setText("");
                        break;
                    case "=":
                        num2 = Double.parseDouble(textField.getText());
                        switch (operator) {
                            case '/':
                                result = num1 / num2;
                                break;
                            case '*':
                                result = num1 * num2;
                                break;
                            case '-':
                                result = num1 - num2;
                                break;
                            case '+':
                                result = num1 + num2;
                                break;
                        }
                        textField.setText(Double.toString(result));
                        break;
                    default:
                        textField.setText(textField.getText() + text);
                        break;
                }
            }
        });
        container.add(button);
    }

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

该示例使用了Java Swing库构建了一个简单的计算器界面，并实现了基本的加、减、乘、除、等于等计算功能。