MongoDB can connect to Spring Boot in two ways:

• the MongoRepository interface
• the MongoTemplate class.

MongoRepository extends the CrudRepository interface that contains methods to perform basic CRUD operations.

For writing custom queries and aggregations, and for a finer control over query filters, we can use the MongoTemplate class. MongoTemplate class implements interfaces that support operations like

• aggregation
• find
• update
• upsert
• index
• remove

and more.