JTree怎么删除所有节点啊！

Question

root = new DefaultMutableTreeNode("Entities");
model = new DefaultTreeModel(root);
tree = new JTree(model);
(增加节点)
root.removeAllChildren();
model.reload();
tree.updateUI();这样为什么不行删不掉啊！

Answer 1

public void removeSelectionRows(int[] rows)

Answer 2

//删除掉了,除了root
//---初学者import java.awt.Window;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;import javax.swing.JDialog;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.tree.DefaultMutableTreeNode;/* Loon 2005-9-25
 */public class DialogTest {    /**
     * @param args
     */
    public static void main(String[] args) {
        new DialogTest();    }    private JDialog dlg = null;
    private JTree tree = null;
    private JScrollPane treeview = null;    DialogTest() {
        dlg = new JDialog();       
        gettree();
        
        dlg.getContentPane().add(treeview);
        init();        
    }    private JTree gettree(){
        /*创建root*/
        DefaultMutableTreeNode top =
            new DefaultMutableTreeNode("The Java Series");
        createNodes(top);
        tree = new JTree(top);
        treeview = new JScrollPane(tree);        top.removeAllChildren();
        tree.updateUI();
        return tree;
    }
    private void createNodes(DefaultMutableTreeNode top) {
        DefaultMutableTreeNode category = null;
        //DefaultMutableTreeNode book = null;
        
        category = new DefaultMutableTreeNode("Books for Java Programmers");
        top.add(category);
                //...add more books for programmers...        category = new DefaultMutableTreeNode("Books for Java Implementers");
        top.add(category);    }    void init() {
        dlg.setTitle("Dialog Test");
        dlg.setSize(200, 200);
        dlg.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.out.println("Now Closing...");
                Window w = e.getWindow();
                w.setVisible(false);
                w.dispose();
                System.exit(0);
                return;
            }        });
              
       
        dlg.setVisible(true);
    }
}

Answer 3

root.removeAllChildren();
tree.updateUI();这么两句在我这没用啊！！！！我试过了！public void removeSelectionRows(int[] rows)
该怎么用啊！！