To get started with connecting to MongoDB, include the dependency for Spring Boot MongoDB starter in the pom.xml:

    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-data-mongodb</artifactId>
    </dependency>

Let's create a new Entity class Person to store to MongoDB. The following snippet shows a Person class with an ID and a name:

    public class Person {
      @Id
      private String id;
      private String name;
      public Person() {// Make JPA Happy
      }
    public Person(String name) {
      super();
      this.name = name;
     }
   }

We would want to store the Person entities to MongoDB. We would need to create a new repository. The following snippet shows a MongoDB repository:

    public interface PersonMongoDbRepository 
    extends MongoRepository<Person, String> {
      List<Person> findByName(String name);
      Long countByName(String name);
    }

Important things to note are as follows:

• PersonMongoDbRepository extends MongoRepository: MongoRepository is a MongoDB-specific Repository interface
• MongoRepository<Person, String>: We would want to store Person entities that have a key of type String
• List<Person> findByName(String name): A simple method to find a person by name