Neo4j Training Series - Spring Data Neo4j
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The document provides an overview of a presentation on Spring Data Neo4j concepts and application development. It introduces the presenters and outlines the agenda which includes setting up a development environment, creating a basic application with the Neo4j Java Driver, an overview of the Spring Data Neo4j architecture, modeling domain classes, working with repositories, custom queries, projections, the Neo4jTemplate, and testing. It then provides more details on several topics from the agenda through examples and live coding sections.
Neo4j Training Series - Spring Data Neo4j
- 1. © 2023 Neo4j, Inc. All rights reserved. © 2023 Neo4j, Inc. All rights reserved. 1 Spring Data Neo4j Concepts & Application Development Gerrit Meier and Michael Simons, SDN and OGM team @ Neo4j
- 2. © 2023 Neo4j, Inc. All rights reserved. Who are we? Michael Simons Gerrit Meier
- 3. © 2023 Neo4j, Inc. All rights reserved. Who are you? • Java Developer • Graph Specialist • Where are you from? • …
- 4. © 2023 Neo4j, Inc. All rights reserved. Today’s plan • Get your development environment set up (If not already done) • Create Neo4j Java Driver-based Spring Boot applications • Concepts and Architecture of Spring Data Neo4j • Advance to a Spring Data Neo4j application ◦ Modelling ◦ Repositories • Control what gets loaded • Custom queries and projections • Working with Neo4jTemplate • Use Neo4jTemplate features • Testing • Add tests to your application
- 5. © 2023 Neo4j, Inc. All rights reserved. Development environment • (free) Aura instance running • JDK 17 ◦ Driver and Spring Boot • IDE • Allow access to download artifacts from Maven Central • Docker for testing
- 6. © 2023 Neo4j, Inc. All rights reserved. Database preparation
- 7. © 2023 Neo4j, Inc. All rights reserved. Spring Boot application • start.spring.io • no dependencies • Maven/Gradle choose ◦ Choose what you are comfortable with ◦ Will use Maven
- 8. © 2023 Neo4j, Inc. All rights reserved. 8 Live coding / code along Project setup
- 9. © 2023 Neo4j, Inc. All rights reserved. © 2023 Neo4j, Inc. All rights reserved. 9 Practical part Create a Spring Boot application using the Neo4j Java Driver. Todo: • Add Neo4j Java Driver • Configuration in application.properties • Implement CommandLineRunner • Output all Movie-node titles
- 10. © 2023 Neo4j, Inc. All rights reserved. Spring Data Neo4j Architecture Neo4j Java Driver spring-boot-autoconfigure provides
- 11. © 2023 Neo4j, Inc. All rights reserved. Spring Data Neo4j Architecture Neo4j Java Driver spring-boot-starter-data-neo4j spring-boot-autoconfigure provides provides Spring Data Neo4j
- 12. © 2023 Neo4j, Inc. All rights reserved. Spring Data Neo4j Architecture Spring Data Repositories Neo4j Template Neo4j Client Neo4j Java Driver spring-boot-starter-data-neo4j spring-boot-autoconfigure provides provides
- 13. © 2023 Neo4j, Inc. All rights reserved. Spring Data Neo4j Architecture Spring Data Repositories Neo4j Template Neo4j Client Neo4j Java Driver spring-boot-starter-data-neo4j spring-boot-autoconfigure provides provides
- 14. © 2023 Neo4j, Inc. All rights reserved. @Node("Person") public class Actor { @Id public final String name; @Relationship("ACTED_IN") public final List<Movie> movies; public Actor(String name, List<Movie> movies) { this.name = name; this.movies = movies; } } @Node public class Movie { @Id public final String title; public Movie(String title) { this.title = title; } }
- 15. © 2023 Neo4j, Inc. All rights reserved. 15 Live coding / code along Spring Data Neo4j (starter) dependency Model domain classes First repository
- 16. © 2023 Neo4j, Inc. All rights reserved. © 2023 Neo4j, Inc. All rights reserved. 16 Practical part Enrich the application by a PersonRepository with additional functionality. Todo: • Create a repository for the Person • Return Tom Hanks with all Movies, he acted in.
- 17. © 2023 Neo4j, Inc. All rights reserved. @Node public class Person { @Id public final String name; public Person(String name) { this.name = name; this.movies = movies; } } @Node public class Movie { @Id public final String title; @Relationship(type="ACTED_IN", direction= Relationship.Direction.INCOMING) public List<Person> actors; @Relationship(type="DIRECTED", direction= Relationship.Direction.INCOMING) public List<Person> directors; @Relationship(type="PRODUCED", direction= Relationship.Direction.INCOMING) public List<Person> producers; public Movie(String title) { this.title = title; } }
- 18. © 2023 Neo4j, Inc. All rights reserved. More on repositories Custom queries • Form your fetch shape by hand
- 19. © 2023 Neo4j, Inc. All rights reserved. More on repositories Projections • Let SDN form your fetch shape
- 20. © 2023 Neo4j, Inc. All rights reserved. © 2023 Neo4j, Inc. All rights reserved. 20 Practical part Use existing functionality in Spring Data Neo4j to load only the data you are interested in. Todo: • Custom query: Find a Movie by title with just the actors attached • Projection: Find a Movie by title with just the actors (additional PersonProjection)
- 21. © 2023 Neo4j, Inc. All rights reserved. Pitfalls of Sub-Graph loading • Loaded slice is incomplete ◦ SDN takes the object (graph) to persist as the only truth ◦ Relationships will get removed • Open projections (DTOs) will adapt entity metadata and fall back to original query creation ◦ Also in multi-level projections starting with interfaces • Use-case specific projections ◦ A lot of interfaces/classes for each use-case
- 22. © 2023 Neo4j, Inc. All rights reserved. 22 Live coding / code along Neo4jTemplate with Projections
- 23. © 2023 Neo4j, Inc. All rights reserved. © 2023 Neo4j, Inc. All rights reserved. 23 Practical part Use projections for save operations. Todo: • Load Movie via Neo4jTemplate the Movie -> Actor projection • Edit the Movie (release year) and call save • Ensure that all relationships still exist
- 24. © 2023 Neo4j, Inc. All rights reserved. Testing • Testslice @DataNeo4jTest ◦ Set up transaction manager, repositories, etc. • Testcontainers Neo4j ◦ Docker based solution to run integration tests
- 25. © 2023 Neo4j, Inc. All rights reserved. © 2023 Neo4j, Inc. All rights reserved. 25 Practical part Use projections for save operations. Todo: • Load Movie via Neo4jTemplate the Movie -> Actor projection • Edit the Movie (release year) and call save • Ensure that all relationships still exist
- 26. © 2023 Neo4j, Inc. All rights reserved. ..there is more, but just so little time • Reactive support • More query styles, like find by example • Fluent Neo4jClient API • …
- 27. © 2023 Neo4j, Inc. All rights reserved. Stay connected • GitHub project pages ◦ https://github.com/spring-projects/spring-data-neo4j • Neo4j Community ◦ https://community.neo4j.com/c/drivers-stacks/spring-data-neo4j-ogm/30 • Developer Blog ◦ https://medium.com/neo4j
- 28. © 2023 Neo4j, Inc. All rights reserved. © 2023 Neo4j, Inc. All rights reserved. 28 Thank you!