java tree自动展开树

package com.EditJTree;

import java.awt.Dimension;
import java.awt.Rectangle;
import java.util.Enumeration;

import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.tree.TreeNode;
import javax.swing.tree.TreePath;

  //java tree自动展开树
public class JTreeTest extends JFrame {  

    //增加带滚动条容器  
    JScrollPane jScrollPane1 = new JScrollPane();  

    //创建树对象  
    JTree treeObj = new JTree();  

    public JTreeTest () {  
        try {  
            jbInit();  
        } catch (Exception exception) {  
            exception.printStackTrace();  
        }  
    }

    private void jbInit() throws Exception {  
        getContentPane().setLayout(null);  
        setSize(new Dimension(434, 347));  
        setTitle("JTree Test");  
        jScrollPane1.setBounds(new Rectangle(9, 9, 429, 317));  
        this.getContentPane().add(jScrollPane1);  
        expandTree(treeObj);  
        jScrollPane1.getViewport().add(treeObj);  
        setVisible(true);
    }  

    /**完全展开一个JTree      
     * @param tree JTree 
    */  
    public static void expandTree(JTree tree) {  
        TreeNode root = (TreeNode) tree.getModel().getRoot();  
        expandAll(tree, new TreePath(root), true);  
    }  

    /**      
    * 完全展开或关闭一个树,用于递规执行      
     * @param tree JTree      
    * @param parent 父节点      
     * @param expand 为true则表示展开树,否则为关闭整棵树      
     */  
    private static void expandAll(JTree tree, TreePath parent, boolean expand) {  

        //Traverse children  
        TreeNode node = (TreeNode) parent.  
                        getLastPathComponent();  
        if (node.getChildCount() >= 0) {  
            for (Enumeration e = node.children(); e.hasMoreElements(); ) {  
                TreeNode n = (TreeNode) e.nextElement();  
                TreePath path = parent.pathByAddingChild(n);  
                expandAll(tree, path, expand);  
            }  
        }   

        if (expand) {  
            tree.expandPath(parent);  
        } else {  
            tree.collapsePath(parent);  
        }  
    }  
    public static void main(String[] args) {
    JTreeTest dJTreeTest = new JTreeTest();
    }
}