public void  mysql2mongo(String src_db,String tar_db){

        MySqlConnector mySqlConnector = new MySqlConnector();

        mysql_conn = mySqlConnector.getConnection(src_db);
        PropertiesReader p = PropertiesReader.getInstance();
        MongoConnector mongoConnector = new MongoConnector();
        Mongo mongo = mongoConnector.getDb();
        DB mongodb = mongo.getDB(tar_db);

        try{
            for(String table_name : MySqlHelper.getTables(mysql_conn)){
                ResultSet records = MySqlHelper.selectAll(mysql_conn,table_name);
                transfer(records,table_name,mongodb);
            }
            log.info(String.format("copy %s tables",table_count));
        }catch (Exception e){
            log.error(e);
        }
        finally {
             IOUtils.close(mysql_conn);
             mongo.close();
        }
    }