jdbc实现事务

//conn需要自己获取，这里我用的时springjdbcTemplate
        Connection conn = null;
        PreparedStatement pstm = null;
        try
        {
            conn = jdbc.getDataSource().getConnection();
        } catch (SQLException e1)
        {
            log.error(e1.getMessage());
            return "服务器错误！";
        }
        FatherModule firstErrorFatherModule = null;
        String sql = null;
        try
        {
            for(FatherModule fatherModule :  fatherModules)
            {
                firstErrorFatherModule = fatherModule; 
                sql = "update sfk_father_module t set t.sort = ? where t.id = ?;";
                pstm = conn.prepareStatement(sql);
               
                pstm.setInt(1, fatherModule.getSort());//注意从1开始
                pstm.setLong(2, fatherModule.getId());
                pstm.executeUpdate();//注意这里为空
                
            }
            conn.commit();
        } catch (SQLException e)
        {
            log.error(e.getMessage());
            try
            {
                conn.rollback();
            } catch (SQLException e1)
            {
               log.error("后台错误");
            }
            return "sortId = "+firstErrorFatherModule.getSort();
        }
        finally
        {
            if(pstm!=null)
            {
                try
                {
                    pstm.close();
                } catch (SQLException e)
                {
                    log.error(e.getMessage());
                }
            }
            
            if(conn!=null)
            {
                try
                {
                    conn.close();
                } catch (SQLException e)
                {
                    log.error(e.getMessage());
                }
            }
        }
        
        return null;