nodemanager.java

代码是hibernate对树的操作

package com.bjsxt.hibernate;

import java.io.File;
import java.util.Iterator;
import java.util.Set;

import org.hibernate.Session;

public class NodeManager {

	private static NodeManager nodeManager;

	private NodeManager() {
	}
 
	public static synchronized NodeManager getInstance() {
		if (nodeManager == null) {
			nodeManager = new NodeManager();
		}

		return nodeManager;
	}

	// 创建树型结构
	public void createTree(String dir) {
		Session session = HibernateUtils.getSession();

		try {
			session.beginTransaction();

			File root = new File(dir);
			saveTree(root, session, null, 0);

			session.getTransaction().commit();
		} catch (RuntimeException e) {
			e.printStackTrace();
			session.getTransaction().rollback();
		} finally {
			HibernateUtils.closeSession(session);
		}
	}

	// 递归创建一棵树
	private void saveTree(File file, Session session, Node parent, int level) {

		if (file == null || !file.exists()) {
			return;
		}

		boolean isLeaf = file.isFile();

		Node node = new Node();
		node.setName(file.getName());
		node.setLevel(level);
		node.setParent(parent);
		node.setLeaf(isLeaf);
		session.save(node);

		File[] subs = file.listFiles();
		if (subs != null && subs.length > 0) {
			for (int i = 0; i < subs.length; i++) {
				saveTree(subs[i], session, node, level + 1);
			}
		}
	}

	public void printTree(int id) {
		Session session = HibernateUtils.getSession();

		try {
			session.beginTransaction();

			Node root = (Node) session.load(Node.class, id);
			printNode(root);

			session.getTransaction().commit();
		} catch (RuntimeException e) {
			e.printStackTrace();
			session.getTransaction().rollback();
		} finally {
			HibernateUtils.closeSession(session);
		}
	}

	private void printNode(Node node) {

		if (node == null) {
			return;
		}
		int level = node.getLevel();
		if (level > 0) {
			for (int i = 0; i < level; i++) {
				System.out.print("  |");
			}
			System.out.print("--");
		}

		System.out.println(node.getName()
				+ (node.isLeaf() ? "" : "[" + node.getChildren().size() + "]"));

		Set children = node.getChildren();
		for (Iterator iter = children.iterator(); iter.hasNext();) {
			Node child = (Node) iter.next();
			printNode(child);
		}
	}
}