请问为什么，使用DBCP连接池得不到记录，而用DBPool却可以

使用DBCP连接池得不到记录，而用DBPool却可以

package dbpooltest;

import java.sql.*;

import snaq.db.ConnectionPoolManager;     

import org.apache.commons.dbcp.BasicDataSource;     

/**

 * 

 * @author lzk

 * 2008-8-25 下午01:49:50

 * @随机查询的实现

 */

public class SelectS {

	private static Connection con = null;

	private static PreparedStatement pstmt = null;

	private static ResultSet rs = null;

	

	

	public static Connection getDBPoolcon(){   //DBPool连接池

		ConnectionPoolManager cpm = null;

		Connection con = null;

		long timeout = 2000;  

		try{

			cpm = ConnectionPoolManager.getInstance("dbpool.properties");

		}catch (Exception e){

			System.out.println("Error Connection.getconnection(): "+e.getMessage());

		}

		

		try{

			con = cpm.getConnection("localpool", timeout);

		}catch (SQLException sqle){

			System.out.println(sqle.getMessage());

		}

		

		return con;

	}

	

	public static Connection getDBCPcon(){   //dbcp连接池

		Connection con  = null;

		String driver = "com.microsoft.sqlserver.jdbc.SQLServerDriver";

		String URL = "jdbc:sqlserver://192.168.168.104:1433;DatabaseName=LTest";

		BasicDataSource bds = new BasicDataSource();

		

		try{

			bds.setDriverClassName(driver);

			bds.setUrl(URL);

			bds.setUsername("sa");

			bds.setPassword("ba123");

			bds.setMaxActive( 50 );    //设置最大活动连接

			bds.setMaxIdle( 10 );      //最大空闲连接

			bds.setMaxWait( 10000 );   //最大等待时间

		}catch(Exception e){

			System.out.println("Error setConnection: "+e.getMessage());

		}

		

		try{

			con = bds.getConnection();

		}catch(Exception e){

			System.out.println("Error getConnection:"+e.getMessage());

		}

		return con;

	}



	

	public static void main(String args[]) throws Exception{	

		PreparedStatement pstmt = null;	



		SelectS ss = new SelectS();

		Connection DBPoolconn = ss.getDBPoolcon();

		Connection dbcpconn = ss.getDBCPcon();

		//System.out.println(dbcpconn);

		

		for(int i=0; i<10; i++){     

			String selectSQL = "SELECT * FROM tablea_1 where num =?";

			pstmt = dbcpconn.prepareStatement(selectSQL);

			//pstmt = DBPoolconn.prepareStatement(selectSQL);

			pstmt.setInt(1, i);

			rs = pstmt.executeQuery();

			

			while(rs.next()){

				System.out.print(rs.getString(1)+" ");

				System.out.println(rs.getString(2));

			}

		}	

	}

}

程序可以正常运行，但就是不知道为什么得不到记录，用DBPool就可以得到记录；
但使用System.out.println(dbcpconn);打印的结果是：
jdbc:sqlserver://192.168.168.104:1433;responseBuffering=full;encrypt=false;databaseName=LTest;selectMethod=direct;trustServerCertificate=false;lastUpdateCount=true;, UserName=sa, Microsoft SQL Server 2005 JDBC Driver