DbUtil查找数据，查找出来的结果最后一列是null？

package com.webchart.dao;

import java.sql.SQLException;
import java.util.List;

import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.sql.DataSource;

import org.apache.commons.dbutils.DbUtils;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanListHandler;

import com.webchart.util.IConstants;
import com.webchart.vo.UserVO;

public class UserInfoDao {


static{ DbUtils.loadDriver(IConstants.DRIVER); }



  public DataSource getDataSou() throws NamingException, SQLException{
final Context context=new InitialContext();

DataSource ds=(DataSource)context.lookup("java:comp/env/mysql");
return ds;
// ds.getConnection();
}


// 插入用户
public int insertUser(final UserVO uv) throws NamingException,
SQLException {
//DbUtils.loadDriver(IConstants.DRIVER);
final Context context = new InitialContext();

final DataSource ds = getDataSou();
final QueryRunner qr = new QueryRunner(ds);
final String sql = "insert into userinfo values(?,?,?,'"+uv.getPimg()+"')";
String x=uv.getPimg();
final String[] param = { (String) uv.getUname(), (String) uv.getUpwd(),
(String) uv.getTname()};
return qr.update(sql, param);
}

// 查找全部用户
public List<UserVO> selectAll() throws NamingException, SQLException {
//DbUtils.loadDriver(IConstants.DRIVER);
final String sql = "select * from userinfo";
final Context context = new InitialContext();
final DataSource ds = getDataSou();
final QueryRunner qr = new QueryRunner(ds);
final List<UserVO> list = (List) qr.query(sql, new BeanListHandler<UserVO>(UserVO.class));
return list;
}

}
全部查找时出来的结果，最后一列的数据为null