java BoxLayout面板的对齐方式

这是一个示例，它将使添加到用作容器的面板的所有JPanel保持左对齐。

   JPanel a = new JPanel();   JPanel b = new JPanel();   JPanel c = new JPanel();   a.setBackground( Color.RED );   b.setBackground( Color.GREEN  );   c.setBackground( Color.BLUE );   a.setMaximumSize( new Dimension(  10, 10) );   b.setMaximumSize( new Dimension(  50, 10) );   a.setAlignmentX( Component.LEFT_ALIGNMENT );//0.0   b.setAlignmentX( Component.LEFT_ALIGNMENT );//0.0   c.setAlignmentX( Component.LEFT_ALIGNMENT );//0.0   JPanel panel = new JPanel();   panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));   panel.add(a);   panel.add(b);   panel.add(c);   int result = JOptionPane.showConfirmDialog(null, panel, "Please enter values.", JOptionPane.OK_CANCEL_OPTION);