This version is still in development and is not considered stable yet. For the latest stable version, please use Spring Data Cassandra 4.4.0! |
Getting Started
Spring Data for Apache Cassandra requires Apache Cassandra 2.1 or later and Datastax Java Driver 4.0 or later. An easy way to quickly set up and bootstrap a working environment is to create a Spring-based project in Spring Tools or use start.spring.io.
Examples Repository
To get a feel for how the library works, you can download and play around with several examples.
Hello World
First, you need to set up a running Apache Cassandra server.
See the
Apache Cassandra Quick Start Guide
for an explanation on how to start Apache Cassandra.
Once installed, starting Cassandra is typically a matter of executing the following command: CASSANDRA_HOME/bin/cassandra -f
.
To create a Spring project in STS, go to File → New → Spring Template Project → Simple Spring Utility Project and press Yes when prompted.
Then enter a project and a package name, such as org.spring.data.cassandra.example
.
Then you can add the following dependency declaration to your pom.xml file’s dependencies
section.
<dependencies>
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-cassandra</artifactId>
<version>4.5.0-SNAPSHOT</version>
</dependency>
</dependencies>
Also, you should change the version of Spring in the pom.xml file to be as follows:
<spring.version>6.2.0</spring.version>
If using a milestone release instead of a GA release, you also need to add the location of the Spring Milestone repository for Maven to your pom.xml file so that it is at the same level of your <dependencies/>
element, as follows:
<repositories>
<repository>
<id>spring-milestone</id>
<name>Spring Maven MILESTONE Repository</name>
<url>https://repo.spring.io/milestone</url>
</repository>
</repositories>
The repository is also browseable here.
You can also browse all Spring repositories here.
Now you can create a simple Java application that stores and reads a domain object to and from Cassandra.
To do so, first create a simple domain object class to persist, as the following example shows:
package org.springframework.data.cassandra.example;
import org.springframework.data.cassandra.core.mapping.PrimaryKey;
import org.springframework.data.cassandra.core.mapping.Table;
@Table
public class Person {
@PrimaryKey private final String id;
private final String name;
private final int age;
public Person(String id, String name, int age) {
this.id = id;
this.name = name;
this.age = age;
}
public String getId() {
return id;
}
private String getName() {
return name;
}
private int getAge() {
return age;
}
@Override
public String toString() {
return String.format("{ @type = %1$s, id = %2$s, name = %3$s, age = %4$d }", getClass().getName(), getId(),
getName(), getAge());
}
}
Next, create the main application to run, as the following example shows:
-
Imperative
-
Reactive
package org.springframework.data.cassandra.example;
import java.util.UUID;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.data.cassandra.core.CassandraOperations;
import org.springframework.data.cassandra.core.CassandraTemplate;
import org.springframework.data.cassandra.core.query.Criteria;
import org.springframework.data.cassandra.core.query.Query;
import com.datastax.oss.driver.api.core.CqlSession;
public class CassandraApplication {
private static final Log LOG = LogFactory.getLog(CassandraApplication.class);
private static Person newPerson(String name, int age) {
return new Person(UUID.randomUUID().toString(), name, age);
}
public static void main(String[] args) {
CqlSession cqlSession = CqlSession.builder().withKeyspace("mykeyspace").build();
CassandraOperations template = new CassandraTemplate(cqlSession);
Person jonDoe = template.insert(newPerson("Jon Doe", 40));
LOG.info(template.selectOne(Query.query(Criteria.where("id").is(jonDoe.getId())), Person.class).getId());
template.truncate(Person.class);
cqlSession.close();
}
}
package org.springframework.data.cassandra.example;
import reactor.core.publisher.Mono;
import java.util.UUID;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.data.cassandra.core.ReactiveCassandraOperations;
import org.springframework.data.cassandra.core.ReactiveCassandraTemplate;
import org.springframework.data.cassandra.core.cql.session.DefaultBridgedReactiveSession;
import org.springframework.data.cassandra.core.query.Criteria;
import org.springframework.data.cassandra.core.query.Query;
import com.datastax.oss.driver.api.core.CqlSession;
public class ReactiveCassandraApplication {
private static final Log LOG = LogFactory.getLog(ReactiveCassandraApplication.class);
private static Person newPerson(String name, int age) {
return new Person(UUID.randomUUID().toString(), name, age);
}
public static void main(String[] args) {
CqlSession cqlSession = CqlSession.builder().withKeyspace("mykeyspace").build();
ReactiveCassandraOperations template = new ReactiveCassandraTemplate(new DefaultBridgedReactiveSession(cqlSession));
Mono<Person> jonDoe = template.insert(newPerson("Jon Doe", 40));
jonDoe.flatMap(it -> template.selectOne(Query.query(Criteria.where("id").is(it.getId())), Person.class))
.doOnNext(it -> LOG.info(it.toString()))
.then(template.truncate(Person.class))
.block();
cqlSession.close();
}
}
Even in this simple example, there are a few notable things to point out:
-
You can create an instance of
CassandraTemplate
(orReactiveCassandraTemplate
for reactive usage) with a CassandraCqlSession
. -
You must annotate your POJO as a Cassandra
@Table
entity and also annotate the@PrimaryKey
. Optionally, you can override these mapping names to match your Cassandra database table and column names. -
You can either use raw CQL or the Driver
QueryBuilder
API to construct your queries.