用Java或者在jsp页面中不知道这种下拉框怎么做？

Question

用Java或者在jsp页面中不知道这种下拉框怎么做？上面的是下拉框可以分为两列，下面的是可以新增或者清空，有谁知道？
图见下:
http://blog.163.com/yuguichong1984/

Answer 1

下面的代码是你第一个要求的简单实现，比较简陋，参考一下吧！/*
 * ComData.java
 */
 
public class ComData
{
String left;
String right;

public ComData(String left, String right)
{
this.left = left;
this.right = right;
}

public String toString()
{
return left+"|"+right;
}
}/*
 * MyCellReaderer.java
 */import javax.swing.*;
import java.awt.*;public class MyCellRenderer extends JPanel implements ListCellRenderer {
private JLabel left, right;    public MyCellRenderer() {
     this.setLayout(new GridLayout(1,2));
     left = new JLabel();
     right = new JLabel();
     this.add(left);
     this.add(right);
        setOpaque(true);
    }
    
    public void paintComponent(Graphics g)
    {
     super.paintComponent(g);
     g.drawRect(0,0, this.getWidth()/2, this.getHeight());
     g.drawRect(this.getWidth()/2, 0, this.getWidth()/2, this.getHeight());
    }
    
    public Component getListCellRendererComponent(
        JList list,
        Object value,
        int index,
        boolean isSelected,
        boolean cellHasFocus)
    {
     int pos = value.toString().indexOf("|");
        left.setText(value.toString().substring(0,pos));
        right.setText(value.toString().substring(pos+1));
        setBackground(isSelected ? Color.red : Color.white);
        setForeground(isSelected ? Color.white : Color.black);
        return this;
    }
}/* 
 * Test.java
 */
import javax.swing.*;
import java.awt.*;public class Test extends JFrame
{
private MyCellRenderer mc = new MyCellRenderer();
private JComboBox jcb = new JComboBox();
private DefaultComboBoxModel dcm = new DefaultComboBoxModel();

public Test()
{
dcm.addElement(new ComData("1","Data-1"));
dcm.addElement(new ComData("2","Data-2"));
dcm.addElement(new ComData("3","Data-3"));
dcm.addElement(new ComData("4","Data-4"));

jcb.setModel(dcm);

jcb.setRenderer(mc);

this.getContentPane().add(jcb, BorderLayout.NORTH);

pack();

this.setVisible(true);
}

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