daotest.java

生成动态树

package com.dao;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;

public class DaoTest {
	Connection con = null;

	public Connection getConnection() {
		Connection conn = null;
		String url = "jdbc:mysql://localhost/test?useUnicode=true&characterEncoding=utf8";
		String user = "root";
		String password = "root";
		try {
			if (conn == null) {
				Class.forName("com.mysql.jdbc.Driver").newInstance();
				conn = DriverManager.getConnection(url, user, password);
			}
		} catch (Exception e) {
			System.out.println("无法连接到指定数据库");
			return null;
		} finally {
			url = null;
			user = null;
			password = null;
		}
		return conn;
	}

	public ArrayList<Nodes> getNodeInfo() {
		String sql = "select nodeId ,parentId ,hrefAddress ,nodeName from tree_table order by id ";
		PreparedStatement pre = null;
		Connection conn = null;
		conn = getConnection();
		ResultSet rs = null;
		ArrayList<Nodes> list = new ArrayList<Nodes>();
		try {
			pre = conn.prepareStatement(sql);
			rs =pre.executeQuery();
			while (rs.next()){
				Nodes node = new Nodes();
				node.setHrefAddress(rs.getString("hrefAddress"));
				node.setNodeId(rs.getString("nodeId"));
				node.setParentId(rs.getString("parentId"));
				node.setNodeName(rs.getString("nodeName"));
				list.add(node);
			}
			rs.close();
			pre.close();
			conn.close();
		} catch (SQLException e) {
			e.printStackTrace();
		}finally{
			 pre = null;
			 conn = null;
			 rs = null;
		}
        return list;
	}

}