public static IRLibIndex getFromDB(MySqlClass mysql, String fileName, String path) {
    DateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    List<IRLibFile> iRLibFileList = new ArrayList<IRLibFile>();
    try {
      mysql.conn.setAutoCommit(false);
    } catch (SQLException e1) {
      e1.printStackTrace();
    }

    String sql2 =
        "select  "
            + " filename       ,"
            + "path,"
            + "date_format(createtime,'%Y-%m-%d %H:%i:%S'),"
            + "date_format(modifytime,'%Y-%m-%d %H:%i:%S'),"
            + "filesize, "
            + "recordCount "
            + " from "
            + IRLibFile.iRLibTable
            + ";";
    System.out.println("query:" + sql2);
    String res2 = mysql.select(sql2);
    System.out.println("get from mysql:\n" + res2);
    if (res2 == null || res2 == "") {
      System.err.println("ERROR:empty query by : " + sql2);
      return null;
    } else {
      String[] line = res2.split("\n");
      for (int i = 0; i < line.length; i++) {
        String[] index = line[i].split(",");
        IRLibFile irLibFile = new IRLibFile();
        irLibFile.fileName = index[0];
        irLibFile.path = index[1];
        try {
          irLibFile.setCreateTime(sdf.parse(index[2]));
          irLibFile.setModifyTime(sdf.parse(index[3]));
        } catch (ParseException e) {
          e.printStackTrace();
        }
        irLibFile.fileSize = Integer.parseInt(index[4]);
        irLibFile.recordCount = Integer.parseInt(index[5]);
        iRLibFileList.add(irLibFile);
      }
    }
    try {
      mysql.conn.commit();
    } catch (SQLException e) {
      e.printStackTrace();
    }
    return new IRLibIndex(iRLibFileList);
  }
 public int saveToDB(MySqlClass mysql) {
   for (IRLibFile ir : this.iRLibFileList) {
     ir.saveToDB(mysql);
   }
   return this.iRLibFileList.size();
 }