用gava做一个GUI计算器，能实现加减乘除，但是除法如果除数为0会窗口跳出异常

好的，那我们可以使用Java Swing库来实现这个GUI计算器。下面是一个简单的实现示例代码：

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

public class Calculator implements ActionListener {
    JFrame frame;
    JTextField textField;
    JButton[] numberButtons = new JButton[10];
    JButton[] functionButtons = new JButton[9];
    JButton addButton, subButton, mulButton, divButton;
    JButton decimalButton, equalsButton, deleteButton, clearButton;
    JPanel panel;

    double num1 = 0, num2 = 0, result = 0;
    char operator;

    Calculator() {
        frame = new JFrame("Calculator");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(420, 550);
        frame.setLayout(null);

        textField = new JTextField();
        textField.setBounds(50, 25, 300, 50);
        textField.setFont(new Font("Arial", Font.PLAIN, 32));
        textField.setEditable(false);

        addButton = new JButton("+");
        subButton = new JButton("-");
        mulButton = new JButton("*");
        divButton = new JButton("/");
        decimalButton = new JButton(".");
        equalsButton = new JButton("=");
        deleteButton = new JButton("Delete");
        clearButton = new JButton("Clear");

        functionButtons[0] = addButton;
        functionButtons[1] = subButton;
        functionButtons[2] = mulButton;
        functionButtons[3] = divButton;
        functionButtons[4] = decimalButton;
        functionButtons[5] = equalsButton;
        functionButtons[6] = deleteButton;
        functionButtons[7] = clearButton;

        for (int i = 0; i < 8; i++) {
            functionButtons[i].addActionListener(this);
            functionButtons[i].setFont(new Font("Arial", Font.PLAIN, 18));
        }

        for (int i = 0; i < 10; i++) {
            numberButtons[i] = new JButton(String.valueOf(i));
            numberButtons[i].addActionListener(this);
            numberButtons[i].setFont(new Font("Arial", Font.PLAIN, 18));
        }

        deleteButton.setBounds(50, 430, 145, 50);
        clearButton.setBounds(205, 430, 145, 50);

        panel = new JPanel();
        panel.setBounds(50, 100, 300, 300);
        panel.setLayout(new GridLayout(4, 4, 10, 10));
        panel.setBackground(Color.gray);

        panel.add(numberButtons[1]);
        panel.add(numberButtons[2]);
        panel.add(numberButtons[3]);
        panel.add(addButton);
        panel.add(numberButtons[4]);
        panel.add(numberButtons[5]);
        panel.add(numberButtons[6]);
        panel.add(subButton);
        panel.add(numberButtons[7]);
        panel.add(numberButtons[8]);
        panel.add(numberButtons[9]);
        panel.add(mulButton);
        panel.add(decimalButton);
        panel.add(numberButtons[0]);
        panel.add(equalsButton);
        panel.add(divButton);

        frame.add(panel);
        frame.add(deleteButton);
        frame.add(clearButton);
        frame.add(textField);
        frame.setVisible(true);
    }

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

    @Override
    public void actionPerformed(ActionEvent e) {
        for (int i = 0; i < 10; i++) {
            if (e.getSource() == numberButtons[i]) {
                textField.setText(textField.getText() + String.valueOf(i));
            }
        }

        if (e.getSource() == decimalButton) {
            textField.setText(textField.getText() + ".");
        }

        if (e.getSource() == addButton) {
            num1 = Double.parseDouble(textField.getText());
            operator = '+';
            textField.setText("");
        }

        if (e.getSource() == subButton) {
            num1 = Double.parseDouble(textField.getText());
            operator = '-';
            textField.setText("");
        }

        if (e.getSource() == mulButton) {
            num1 = Double.parseDouble(textField.getText());
            operator = '*';
            textField.setText("");
        }

        if (e.getSource() == divButton) {
            num1 = Double.parseDouble(textField.getText());
            operator = '/';
            textField.setText("");
        }

        if (e.getSource() == equalsButton) {
            num2 = Double.parseDouble(textField.getText());

            switch (operator) {
                case '+':
                    result = num1 + num2;
                    break;
                case '-':
                    result = num1 - num2;
                    break;
                case '*':
                    result = num1 * num2;
                    break;
                case '/':
                    if (num2 == 0) {
                        JOptionPane.showMessageDialog(frame, "除数不能为0！");
                        textField.setText("");
                        num1 = 0;
                        num2 = 0;
                        result = 0;
                    } else {
                        result = num1 / num2;
                    }
                    break;
            }

            textField.setText(String.valueOf(result));
            num1 = result;
        }

        if (e.getSource() == clearButton) {
            textField.setText("");
            num1 = 0;
            num2 = 0;
            result = 0;
        }

        if (e.getSource() == deleteButton) {
            String string = textField.getText();
            textField.setText("");
            for (int i = 0; i < string.length() - 1; i++) {
                textField.setText(textField.getText() + string.charAt(i));
            }
        }
    }
}

这段代码中，我们创建了一个 `Calculator` 类，实现了 `ActionListener` 接口。在 `Calculator` 类的构造函数中，我们创建了一个 `JFrame` 窗口，并添加了一些按钮和文本框，用于实现加减乘除计算器的功能。在 `actionPerformed()` 方法中，我们根据用户点击的按钮来执行相应的操作，包括数字按钮、小数点按钮、加减乘除按钮、等于号按钮、删除按钮和清除按钮。当除数为0时，我们使用 `JOptionPane` 类弹出一个错误消息框告诉用户除数不能为0。

你可以在本地编译和运行这段代码，测试一下这个GUI计算器的功能。