When configuring MongoDB authentication, the configuration needs to happen either through the URI or through individual properties. Specifying spring.data.mongodb.uri ignores spring.data.mongodb.username and spring.data.mongodb.password properties as we assume the ConnectionString encapsulates all details.

In cases where endpoint config is provided with through an URL but authentication should be provided through properties (e.g. Vault, external property sources), it is not possible to do so.

In other areas, such as JDBC, some drivers can accept authentication as part of the JDBC URL and username/password properties are considered additionally.

Ideally, when both, URI and authentication, are configured, spring.data.mongodb.username overrides what is specified through the connection string.

Related tickets:

• Introduce spring.data.mongodb.protocol to allow the MongoDB protocol to be customized when not using spring.data.mongodb.uri #43851
• Add usability of username password for mongodb+srv #37100
• MongoDB URI property doesn't interact well with Spring Cloud Vault #17215