public static Connection createConn(){
		Connection conn = null; 
		try {
			Class.forName((String)props.get("driver"));
			//ip地址 + 数据库名称
			conn = DriverManager.getConnection((String)props.get("url"), (String)props.get("username"), (String)props.get("password"));
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return conn;
	}