创建一个Java可视化计算器的界面，并显示0到9的按钮与加减乘除按钮，只需要显示计算器的界面不需要使用，并显示输出结果

这是一个使用Java Swing库创建的简单可视化计算器界面，包含0到9的数字按钮和加减乘除等运算符号按钮。可以通过监听按钮事件，将用户输入的数字和运算符进行处理，最终输出计算结果。

import java.awt.EventQueue;
import java.awt.Font;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;

public class Calculator {
    
    private JFrame frame;
    private JTextField textField;
    private double num1, num2, result;
    private String operator;
    
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    Calculator window = new Calculator();
                    window.frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    public Calculator() {
        initialize();
    }

    private void initialize() {
        frame = new JFrame();
        frame.setBounds(100, 100, 300, 400);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().setLayout(null);
        
        textField = new JTextField();
        textField.setFont(new Font("Lucida Grande", Font.PLAIN, 20));
        textField.setBounds(20, 20, 260, 50);
        textField.setEditable(false);
        frame.getContentPane().add(textField);
        textField.setColumns(10);
        
        JPanel panel = new JPanel();
        panel.setBounds(20, 80, 260, 260);
        panel.setLayout(new GridLayout(4, 4, 5, 5));
        frame.getContentPane().add(panel);
        
        JButton btn7 = new JButton("7");
        btn7.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                textField.setText(textField.getText() + "7");
            }
        });
        panel.add(btn7);
        
        JButton btn8 = new JButton("8");
        btn8.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                textField.setText(textField.getText() + "8");
            }
        });
        panel.add(btn8);
        
        JButton btn9 = new JButton("9");
        btn9.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                textField.setText(textField.getText() + "9");
            }
        });
        panel.add(btn9);
        
        JButton btnPlus = new JButton("+");
        btnPlus.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                num1 = Double.parseDouble(textField.getText());
                operator = "+";
                textField.setText("");
            }
        });
        panel.add(btnPlus);
        
        JButton btn4 = new JButton("4");
        btn4.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                textField.setText(textField.getText() + "4");
            }
        });
        panel.add(btn4);
        
        JButton btn5 = new JButton("5");
        btn5.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                textField.setText(textField.getText() + "5");
            }
        });
        panel.add(btn5);
        
        JButton btn6 = new JButton("6");
        btn6.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                textField.setText(textField.getText() + "6");
            }
        });
        panel.add(btn6);
        
        JButton btnMinus = new JButton("-");
        btnMinus.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                num1 = Double.parseDouble(textField.getText());
                operator = "-";
                textField.setText("");
            }
        });
        panel.add(btnMinus);
        
        JButton btn1 = new JButton("1");
        btn1.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                textField.setText(textField.getText() + "1");
            }
        });
        panel.add(btn1);
        
        JButton btn2 = new JButton("2");
        btn2.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                textField.setText(textField.getText() + "2");
            }
        });
        panel.add(btn2);
        
        JButton btn3 = new JButton("3");
        btn3.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                textField.setText(textField.getText() + "3");
            }
        });
        panel.add(btn3);
        
        JButton btnMultiply = new JButton("*");
        btnMultiply.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                num1 = Double.parseDouble(textField.getText());
                operator = "*";
                textField.setText("");
            }
        });
        panel.add(btnMultiply);
        
        JButton btn0 = new JButton("0");
        btn0.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                textField.setText(textField.getText() + "0");
            }
        });
        panel.add(btn0);
        
        JButton btnDot = new JButton(".");
        btnDot.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                if (!textField.getText().contains(".")) {
                    textField.setText(textField.getText() + ".");
                }
            }
        });
        panel.add(btnDot);
        
        JButton btnEqual = new JButton("=");
        btnEqual.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                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));
            }
        });
        panel.add(btnEqual);
        
        JButton btnDivide = new JButton("/");
        btnDivide.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                num1 = Double.parseDouble(textField.getText());
                operator = "/";
                textField.setText("");
            }
        });
        panel.add(btnDivide);
    }

}