To connect to the ReactiveMongo database, Spring Boot provides a starter project--Spring Boot Reactive MongoDB Starter. Let's add this to our the pom.xml file:

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

The spring-boot-starter-data-mongodb-reactive starter brings in the spring-data-mongodb, mongodb-driver-async, and mongodb-driver-reactivestreams dependencies. The following snippet shows the important dependencies in the spring-boot-starter-data-mongodb-reactive starter:

    <dependency>
      <groupId>org.springframework.data</groupId>
      <artifactId>spring-data-mongodb</artifactId>
      <exclusions>
       <exclusion>
         <groupId>org.mongodb</groupId>
         <artifactId>mongo-java-driver</artifactId>
       </exclusion>
      <exclusion>
        <groupId>org.slf4j</groupId>
        <artifactId>jcl-over-slf4j</artifactId>
      </exclusion>
     </exclusions>
    </dependency>
    <dependency>
     <groupId>org.mongodb</groupId>
     <artifactId>mongodb-driver</artifactId>
    </dependency>
    <dependency>
     <groupId>org.mongodb</groupId>
     <artifactId>mongodb-driver-async</artifactId>
    </dependency>
    <dependency>
     <groupId>org.mongodb</groupId>
     <artifactId>mongodb-driver-reactivestreams</artifactId>
    </dependency>
    <dependency>
     <groupId>io.projectreactor</groupId>
     <artifactId>reactor-core</artifactId>
    </dependency>

The EnableReactiveMongoRepositories annotation enables ReactiveMongo features. The following snippet shows it being added to the SpringReactiveExampleApplication class:

    @SpringBootApplication
    @EnableReactiveMongoRepositories
    public class SpringReactiveExampleApplication {