Connect a Spring Boot application to a Cassandra database - step by step

To connect a Spring Boot application to a Cassandra database, follow these steps:

1. Add Dependencies

In your pom.xml (for Maven) or build.gradle (for Gradle), add the necessary dependencies for Spring Boot and Cassandra.

For Maven:

<dependencies>
    <!-- Spring Boot Starter Data Cassandra -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-cassandra</artifactId>
    </dependency>

    <!-- Other dependencies you may need -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
</dependencies>

For Gradle:

dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-data-cassandra'
    implementation 'org.springframework.boot:spring-boot-starter-web'
}

2. Configure application.properties or application.yml

Using application.properties:

spring.data.cassandra.keyspace-name=my_keyspace
spring.data.cassandra.contact-points=127.0.0.1
spring.data.cassandra.port=9042
spring.data.cassandra.local-datacenter=datacenter1
spring.data.cassandra.schema-action=create_if_not_exists

Or using application.yml:

spring:
  data:
    cassandra:
      keyspace-name: my_keyspace
      contact-points: 127.0.0.1
      port: 9042
      local-datacenter: datacenter1
      schema-action: create_if_not_exists

• keyspace-name: The Cassandra keyspace to connect to.
• contact-points: The IP address of the Cassandra cluster nodes (you can add multiple nodes for high availability).
• port: The port on which Cassandra is running (default: 9042).
• local-datacenter: The data center name configured in your Cassandra setup.
• schema-action: Defines how the schema is handled (create_if_not_exists, none, etc.).

3. Create a Cassandra Entity

Define an entity class that maps to a Cassandra table. Use annotations from org.springframework.data.cassandra.core.mapping.

import org.springframework.data.cassandra.core.mapping.Table;
import org.springframework.data.cassandra.core.mapping.PrimaryKey;
import org.springframework.data.cassandra.core.mapping.Column;

@Table
public class User {

    @PrimaryKey
    private String id;

    @Column
    private String name;

    @Column
    private int age;

    // Getters and Setters
}

4. Create a Repository Interface

Use Spring Data's CassandraRepository to interact with Cassandra.

import org.springframework.data.cassandra.repository.CassandraRepository;

public interface UserRepository extends CassandraRepository<User, String> {
    // You can define custom queries here if needed
}

5. Service or Controller to Use the Repository

Inject the repository into a service or controller class to interact with Cassandra.

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class UserService {

    @Autowired
    private UserRepository userRepository;

    public void saveUser(User user) {
        userRepository.save(user);
    }

    public User findUserById(String id) {
        return userRepository.findById(id).orElse(null);
    }
}

6. Run the Application

Make sure Cassandra is running locally or remotely, and that the connection details in application.properties are correct. Then run your Spring Boot application.

mvn spring-boot:run

or

./gradlew bootRun