用Java设计一个简单计算器，具体要求如下：能够实现加减乘除四则运算及开方，乘方运算。运算结果能正常显示，可以清零。可以查看历史记录。使用页面

好的，我可以为您提供一个简单的Java计算器设计代码，使用Java Swing库来创建GUI界面。以下是主要代码：

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

public class Calculator extends JFrame implements ActionListener {
    private JTextField display = new JTextField(20);
    private double num1, num2, result;
    private String operator;
    private String[] history = new String[10];
    private int index = 0;

    public Calculator() {
        super("简单计算器");

        JPanel panel1 = new JPanel(new GridLayout(4, 4, 5, 5));
        String[] labels = {"7", "8", "9", "+", "4", "5", "6", "-", "1", "2", "3", "*", "0", ".", "=", "/", "√", "x²", "C", "历史记录"};
        for (String label : labels) {
            JButton button = new JButton(label);
            button.setFocusable(false);
            button.addActionListener(this);
            panel1.add(button);
        }

        JPanel panel2 = new JPanel(new BorderLayout());
        panel2.add(display, BorderLayout.NORTH);
        panel2.add(panel1, BorderLayout.CENTER);

        JPanel panel3 = new JPanel(new GridLayout(10, 1));
        for (int i = 0; i < 10; i++) {
            JLabel label = new JLabel();
            panel3.add(label);
        }

        JSplitPane splitPane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, panel2, panel3);
        splitPane.setDividerLocation(250);

        setContentPane(splitPane);
        pack();
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLocationRelativeTo(null);
    }

    public void actionPerformed(ActionEvent e) {
        String command = e.getActionCommand();
        if (command.equals("C")) {
            display.setText("");
        } else if (command.equals("=")) {
            num2 = Double.parseDouble(display.getText());
            if (operator.equals("+")) {
                result = num1 + num2;
            } else if (operator.equals("-")) {
                result = num1 - num2;
            } else if (operator.equals("*")) {
                result = num1 * num2;
            } else if (operator.equals("/")) {
                result = num1 / num2;
            } else if (operator.equals("√")) {
                result = Math.sqrt(num1);
            } else if (operator.equals("x²")) {
                result = Math.pow(num1, 2);
            }
            display.setText(String.valueOf(result));
            String historyItem = num1 + " " + operator + " " + num2 + " = " + result;
            history[index % 10] = historyItem;
            index++;
        } else if (command.equals("历史记录")) {
            for (int i = 0; i < 10; i++) {
                JLabel label = (JLabel) ((JPanel) getContentPane().getComponent(1)).getComponent(i);
                if (history[(index - i - 1) % 10] != null) {
                    label.setText(history[(index - i - 1) % 10]);
                } else {
                    label.setText("");
                }
            }
        } else {
            if (operator == null) {
                num1 = Double.parseDouble(display.getText());
            } else {
                num2 = Double.parseDouble(display.getText());
            }
            operator = command;
            display.setText("");
        }
    }

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

这个计算器可以实现加减乘除四则运算，开方，乘方以及清零功能。它还记录了最近10次计算历史记录，可以在界面上查看。