Cassandra

Cassandra is an open source, distributed database management system designed to handle large amounts of data across many commodity servers. Spring Boot offers auto-configuration for Cassandra and the abstractions on top of it provided by Spring Data Cassandra. There is a spring-boot-starter-data-cassandra “Starter” for collecting the dependencies in a convenient way.

Connecting to Cassandra

You can inject an auto-configured CassandraTemplate or a Cassandra CqlSession instance as you would with any other Spring Bean. The spring.cassandra.* properties can be used to customize the connection. Generally, you provide keyspace-name and contact-points as well the local datacenter name, as shown in the following example:

  • Properties

  • YAML

spring.cassandra.keyspace-name=mykeyspace
spring.cassandra.contact-points=cassandrahost1:9042,cassandrahost2:9042
spring.cassandra.local-datacenter=datacenter1
spring:
  cassandra:
    keyspace-name: "mykeyspace"
    contact-points: "cassandrahost1:9042,cassandrahost2:9042"
    local-datacenter: "datacenter1"

If the port is the same for all your contact points you can use a shortcut and only specify the host names, as shown in the following example:

  • Properties

  • YAML

spring.cassandra.keyspace-name=mykeyspace
spring.cassandra.contact-points=cassandrahost1,cassandrahost2
spring.cassandra.local-datacenter=datacenter1
spring:
  cassandra:
    keyspace-name: "mykeyspace"
    contact-points: "cassandrahost1,cassandrahost2"
    local-datacenter: "datacenter1"
Those two examples are identical as the port default to 9042. If you need to configure the port, use spring.cassandra.port.

The Cassandra driver has its own configuration infrastructure that loads an application.conf at the root of the classpath.

Spring Boot does not look for such a file by default but can load one using spring.cassandra.config. If a property is both present in spring.cassandra.* and the configuration file, the value in spring.cassandra.* takes precedence.

For more advanced driver customizations, you can register an arbitrary number of beans that implement DriverConfigLoaderBuilderCustomizer. The CqlSession can be customized with a bean of type CqlSessionBuilderCustomizer.
If you use CqlSessionBuilder to create multiple CqlSession beans, keep in mind the builder is mutable so make sure to inject a fresh copy for each session.

The following code listing shows how to inject a Cassandra bean:

  • Java

  • Kotlin

import org.springframework.data.cassandra.core.CassandraTemplate;
import org.springframework.stereotype.Component;

@Component
public class MyBean {

	private final CassandraTemplate template;

	public MyBean(CassandraTemplate template) {
		this.template = template;
	}

	// ...

	public long someMethod() {
		return this.template.count(User.class);
	}

}
import org.springframework.data.cassandra.core.CassandraTemplate
import org.springframework.stereotype.Component

@Component
class MyBean(private val template: CassandraTemplate) {

	// ...

	fun someMethod(): Long {
		return template.count(User::class.java)
	}

}

If you add your own @Bean of type CassandraTemplate, it replaces the default.

Spring Data Cassandra Repositories

Spring Data includes basic repository support for Cassandra. Currently, this is more limited than the JPA repositories discussed earlier and needs @Query annotated finder methods.

For complete details of Spring Data Cassandra, see the reference documentation.