public Connection connectToDB() throws CustomerizedException{
		if(this.DriverName != null && 
				this.URL != null && this.UserName != null &&
				this.PassWord != null && this.conn == null){			
			try {
				Class.forName(this.DriverName);
				this.conn = DriverManager.getConnection(this.URL,this.UserName,this.PassWord);
			} catch (SQLException e) {
				log.error("Connect to DB meet trouble,err: "+e.getLocalizedMessage());
				e.printStackTrace();
			} catch (ClassNotFoundException e) {
				log.error("Adding driver meet trouble,err: "+e.getLocalizedMessage());
			}
		}else{
			throw new CustomerizedException("Can't connect to the DB!");
		}
		log.info("Connecting to DB successfully!");
		return conn;
	}