as MarkusWMahlberg 正确注意到，有必要记下连接字符串中的数据库名称。

As MarkusWMahlberg correctly noted, it is necessary to note the database name in the connection string.

例如：

String mongoClientURI = "mongodb://" + DB_SRV_USR + ":" + DB_SRV_PWD + "@" + DB_URL + ":" + DB_PORT + "/" + dbName;