请用java GUI编写一个运算器应用程序。要求实现运算器中常用的功能（＋，－，＊，、）。

好的，我可以为您提供一个简单的Java GUI运算器代码实现。请注意，这只是一个基本的示例，您可以根据自己的需求进行修改和改进。

import java.awt.Color;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;

public class Calculator extends JFrame implements ActionListener {
    private static final long serialVersionUID = 1L;
    
    private JLabel label1, label2, label3;
    private JTextField text1, text2, text3;
    private JButton buttonAdd, buttonSub, buttonMul, buttonDiv;
    
    public Calculator() {
        super("Calculator");
        setSize(400, 300);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLocationRelativeTo(null);
        setResizable(false);
        initComponents();
        setVisible(true);
    }
    
    private void initComponents() {
        JPanel panel = new JPanel();
        panel.setLayout(null);
        panel.setBackground(Color.WHITE);
        
        label1 = new JLabel("Number 1:");
        label1.setBounds(50, 50, 100, 30);
        panel.add(label1);
        
        text1 = new JTextField();
        text1.setBounds(160, 50, 150, 30);
        panel.add(text1);
        
        label2 = new JLabel("Number 2:");
        label2.setBounds(50, 100, 100, 30);
        panel.add(label2);
        
        text2 = new JTextField();
        text2.setBounds(160, 100, 150, 30);
        panel.add(text2);
        
        buttonAdd = new JButton("+");
        buttonAdd.setBounds(50, 150, 50, 50);
        buttonAdd.setFont(new Font("Arial", Font.BOLD, 20));
        buttonAdd.addActionListener(this);
        panel.add(buttonAdd);
        
        buttonSub = new JButton("-");
        buttonSub.setBounds(120, 150, 50, 50);
        buttonSub.setFont(new Font("Arial", Font.BOLD, 20));
        buttonSub.addActionListener(this);
        panel.add(buttonSub);
        
        buttonMul = new JButton("*");
        buttonMul.setBounds(190, 150, 50, 50);
        buttonMul.setFont(new Font("Arial", Font.BOLD, 20));
        buttonMul.addActionListener(this);
        panel.add(buttonMul);
        
        buttonDiv = new JButton("/");
        buttonDiv.setBounds(260, 150, 50, 50);
        buttonDiv.setFont(new Font("Arial", Font.BOLD, 20));
        buttonDiv.addActionListener(this);
        panel.add(buttonDiv);
        
        label3 = new JLabel("Result:");
        label3.setBounds(50, 220, 100, 30);
        panel.add(label3);
        
        text3 = new JTextField();
        text3.setBounds(160, 220, 150, 30);
        text3.setEditable(false);
        panel.add(text3);
        
        add(panel);
    }
    
    @Override
    public void actionPerformed(ActionEvent e) {
        double num1 = Double.parseDouble(text1.getText());
        double num2 = Double.parseDouble(text2.getText());
        
        if(e.getSource() == buttonAdd) {
            double result = num1 + num2;
            text3.setText(Double.toString(result));
        }
        else if(e.getSource() == buttonSub) {
            double result = num1 - num2;
            text3.setText(Double.toString(result));
        }
        else if(e.getSource() == buttonMul) {
            double result = num1 * num2;
            text3.setText(Double.toString(result));
        }
        else if(e.getSource() == buttonDiv) {
            double result = num1 / num2;
            text3.setText(Double.toString(result));
        }
    }
    
    public static void main(String[] args) {
        new Calculator();
    }
}

这个程序创建了一个简单的GUI界面，包含两个文本框和四个按钮（加、减、乘、除），当用户点击按钮时，程序将读取文本框中的数字，执行相应的运算，并将结果显示在另一个文本框中。