mysql-java关于dbutils的使用

 /*     * 查找评论     */    public List find(String blogID) {        try {            String sql = "select child.commentID,u.userName,child.commentContent,count(child.commentID) depth,child.commentParentID,child.commentTime from comment2 parent,comment2 child,user u where child.blogID = ? and child.blogID = parent.blogID and parent.left<=child.left and parent.right>=child.right and child.userID = u.userID group by child.commentID order by child.left";            Object params[] = { blogID };            List list = qr.query(sql, new BeanListHandler(                    Comment.class), params);             sql = "select u.userName from user u,comment c where c.commentID = ? and u.userID = c.userID";            for (int i = 0; i < list.size(); i++) {                if (list.get(i).getCommentParentID() != null) {                    Object params1[] = { list.get(i).getCommentParentID() };//                  String userName = qr.query(sql,new ScalarHandler(), params1);                    Comment commentParent = qr.query(sql, new BeanHandler(Comment.class), params1);                    System.out.println(sql+ commentParent.getUserName() );                      list.get(i).setCommentParent(commentParent);                }            }            return list;        } catch (SQLException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }        return null;    }

上面代码中，使用了dbutils这个工具，第一个sql语句能顺利查出结果，第二个sql语句什么都查不到，不管是用ScalarHandler还是beanHandler接收查到的数据都是空(userName和commentParent都为空)，sql语句我在mysql试过了没问题能查出东西，param1[]里的东西也能正确传进去，可是就是查不出来，希望高手帮帮忙，帮我找找问题。