Neo4j Spring Data Skill

Neo4j Spring Data Skill

Status: Draft / WIP — Content is a placeholder. Reference files to be added.

When to Use

• Configuring Spring Boot with Neo4j (spring-boot-starter-data-neo4j)
• Writing @Node entity classes and @Relationship mappings
• Defining Neo4jRepository / ReactiveNeo4jRepository interfaces
• Writing @Query annotations with Cypher on repository methods
• Using Spring projections (interface-based or DTO-based) with Neo4j
• Configuring application.yml for Neo4j connection
• Spring AI Neo4jVectorStore for vector search in Spring apps

When NOT to Use

• Raw Java driver without Spring → use neo4j-driver-java-skill
• Cypher query authoring → use neo4j-cypher-skill
• Driver version upgrades → use neo4j-migration-skill

Setup

pom.xml:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-neo4j</artifactId>
</dependency>

application.yml:

spring:
  neo4j:
    uri: ${NEO4J_URI:neo4j+s://host.databases.neo4j.io}
    authentication:
      username: ${NEO4J_USERNAME:neo4j}
      password: ${NEO4J_PASSWORD}
  data:
    neo4j:
      database: ${NEO4J_DATABASE:neo4j}

Core Patterns

Entity mapping

import org.springframework.data.neo4j.core.schema.*;

@Node("Person")
public class Person {
    @Id @GeneratedValue private Long id;
    private String name;
    private String email;

    @Relationship(type = "KNOWS", direction = Relationship.Direction.OUTGOING)
    private List<Person> friends = new ArrayList<>();
}

Repository

Security: @Query annotations MUST use $parameter placeholders — never string-concatenate user input into Cypher. Spring Data does not sanitize string interpolation; concatenation is a Cypher injection hole.

import org.springframework.data.neo4j.repository.Neo4jRepository;

public interface PersonRepository extends Neo4jRepository<Person, Long> {
    Optional<Person> findByName(String name);

    // CORRECT: $name is a bound parameter
    @Query("MATCH (p:Person {name: $name})-[:KNOWS]->(f) RETURN f")
    List<Person> findFriendsOf(String name);

    // WRONG: never do this
    // @Query("MATCH (p:Person {name: '" + name + "'}) RETURN p")  // injection risk
}

Reactive repository

import org.springframework.data.neo4j.repository.ReactiveNeo4jRepository;
import reactor.core.publisher.Flux;

public interface PersonRepository extends ReactiveNeo4jRepository<Person, Long> {
    @Query("MATCH (p:Person {name: $name})-[:KNOWS]->(f) RETURN f")
    Flux<Person> findFriendsOf(String name);
}

Checklist

• @Node uses a specific label string (not just @Node with default class name)
• @Id @GeneratedValue on internal ID field (or @Id on a business key with constraint)
• @Relationship direction is explicit (OUTGOING / INCOMING)
• @Query Cypher uses $paramName parameters (not concatenation)
• Database name configured in application.yml (avoids default DB ambiguity)
• Unique constraint in DB for any business key used in repository lookups

References

• Spring Data Neo4j Reference
• GraphAcademy: Building Neo4j Applications with Spring Data
• Spring AI Neo4jVectorStore