vant代码实现下拉框分别选择年月日

import java.awt.BorderLayout; import java.awt.EventQueue; import java.awt.FlowLayout; import javax.swing.JComboBox; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel;

public class DropdownExample extends JFrame {

private JPanel contentPane;

public static void main(String[] args) {
    EventQueue.invokeLater(() -> {
        try {
            DropdownExample frame = new DropdownExample();
            frame.setVisible(true);
        } catch (Exception e) {
            e.printStackTrace();
        }
    });
}

public DropdownExample() {
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setBounds(100, 100, 300, 150);
    contentPane = new JPanel();
    contentPane.setLayout(new BorderLayout(0, 0));
    setContentPane(contentPane);

    JPanel panel = new JPanel();
    contentPane.add(panel, BorderLayout.CENTER);
    panel.setLayout(new FlowLayout(FlowLayout.CENTER, 5, 5));

    JComboBox<Integer> yearComboBox = new JComboBox<>();
    for (int i = 1900; i <= 2100; i++) {
        yearComboBox.addItem(i);
    }
    panel.add(new JLabel("Year:"));
    panel.add(yearComboBox);

    JComboBox<String> monthComboBox = new JComboBox<>();
    for (int i = 1; i <= 12; i++) {
        monthComboBox.addItem(String.format("%02d", i));
    }
    panel.add(new JLabel("Month:"));
    panel.add(monthComboBox);

    JComboBox<String> dayComboBox = new JComboBox<>();
    for (int i = 1; i <= 31; i++) {
        dayComboBox.addItem(String.format("%02d", i));
    }
    panel.add(new JLabel("Day:"));
    panel.add(dayComboBox);
}