使用具有默认约束的 GridBagLayout。下面是一个小的演示代码:
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class TestVerticalAlignement {
    protected void initUI() {
        final JFrame frame = new JFrame();
        frame.setTitle("Test vertical alignement");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        JPanel panel = new JPanel();
        panel.setLayout(new GridBagLayout());
        GridBagConstraints gbc = new GridBagConstraints();
        JLabel label1 = new JLabel("label1");
        JLabel label2 = new JLabel("label2");
        panel.add(label1, gbc);
        panel.add(label2, gbc);
        frame.add(panel);
        frame.setSize(300, 300);
        frame.setVisible(true);
    }
    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new TestVerticalAlignement().initUI();
            }
        });
    }
}