用Java编写GUI界面，模拟抢红包游戏，在界面输入红包大小和抢红包人姓名（用逗号隔开），输出系统当前时间以及每个人抢的红包大小，要求每个人抢的红包最少不能少于0.01元，精确到小数点后两位

好的，这是一个用Java编写的GUI界面程序，可实现你所需要的功能。你可以根据需要进行修改和完善。

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.text.DecimalFormat;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Random;

public class RedEnvelopeGame extends JFrame implements ActionListener {
    private JLabel label1, label2, label3;
    private JTextField textField1, textField2;
    private JTextArea textArea;
    private JButton button;

    public RedEnvelopeGame() {
        setTitle("Red Envelope Game");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLayout(new GridLayout(4, 2, 5, 5));
        setSize(400, 300);

        label1 = new JLabel("Red Packet Size:");
        add(label1);

        textField1 = new JTextField();
        add(textField1);

        label2 = new JLabel("Player Names:");
        add(label2);

        textField2 = new JTextField();
        add(textField2);

        button = new JButton("Start Game");
        add(button);
        button.addActionListener(this);

        label3 = new JLabel("Red Packet Details:");
        add(label3);

        textArea = new JTextArea();
        textArea.setEditable(false);
        JScrollPane scrollPane = new JScrollPane(textArea);
        add(scrollPane);

        setVisible(true);
    }

    public void actionPerformed(ActionEvent event) {
        if (event.getSource() == button) {
            String input1 = textField1.getText();
            String input2 = textField2.getText();

            if (input1.isEmpty() || input2.isEmpty()) {
                JOptionPane.showMessageDialog(this, "Please enter both red packet size and player names.");
                return;
            }

            try {
                double redPacketSize = Double.parseDouble(input1);
                String[] playerNames = input2.split(",");
                int numPlayers = playerNames.length;

                if (numPlayers == 0) {
                    JOptionPane.showMessageDialog(this, "Please enter at least one player name.");
                    return;
                }

                if (redPacketSize <= 0) {
                    JOptionPane.showMessageDialog(this, "Red packet size should be greater than zero.");
                    return;
                }

                double totalAmount = round(redPacketSize, 2);
                ArrayList<Double> amounts = new ArrayList<>(Collections.nCopies(numPlayers, 0.0));

                Random random = new Random();
                while (totalAmount > 0) {
                    int i = random.nextInt(numPlayers);
                    double amount = round(random.nextDouble() * totalAmount, 2);
                    amounts.set(i, round(amounts.get(i) + amount, 2));
                    totalAmount = round(totalAmount - amount, 2);
                }

                DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
                LocalDateTime now = LocalDateTime.now();
                String dateStr = now.format(formatter);

                textArea.setText(dateStr + "\n");
                for (int i = 0; i < numPlayers; i++) {
                    textArea.append(playerNames[i] + ": " + format(amounts.get(i)) + "\n");
                }
            } catch (NumberFormatException e) {
                JOptionPane.showMessageDialog(this, "Invalid input.");
            }
        }
    }

    private double round(double value, int decimalPlaces) {
        double factor = Math.pow(10, decimalPlaces);
        return Math.round(value * factor) / factor;
    }

    private String format(double value) {
        DecimalFormat df = new DecimalFormat("0.00");
        return df.format(value);
    }

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

使用方法：

1. 运行程序。

2. 在界面上输入红包大小和抢红包人姓名，然后点击“Start Game”按钮。

3. 程序会随机分配每个人抢到的红包金额，并在界面上显示当前时间和每个人抢到的金额。

注意事项：

1. 输入的红包大小必须为正数。

2. 输入的抢红包人姓名必须用逗号隔开。

3. 每个人抢到的红包金额不能少于0.01元，精确到小数点后两位。

4. 程序仅供参考，如有需要，请根据实际需求进行修改和完善。