常见问题解答

<properties>
  <neo4j-java-driver.version>5.4.0</neo4j-java-driver.version>
</properties>

neo4j-java-driver.version = 5.4.0

<dependencyManagement>
    <dependency>
        <groupId>org.neo4j.driver</groupId>
        <artifactId>neo4j-java-driver</artifactId>
        <version>5.4.0</version>
    </dependency>
</dependencyManagement>

spring.data.neo4j.database = yourDatabase

import org.neo4j.springframework.data.core.DatabaseSelection;
import org.neo4j.springframework.data.core.DatabaseSelectionProvider;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.context.SecurityContext;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.security.core.userdetails.User;

@Configuration
public class Neo4jConfig {

	@Bean
	DatabaseSelectionProvider databaseSelectionProvider() {

		return () -> Optional.ofNullable(SecurityContextHolder.getContext()).map(SecurityContext::getAuthentication)
				.filter(Authentication::isAuthenticated).map(Authentication::getPrincipal).map(User.class::cast)
				.map(User::getUsername).map(DatabaseSelection::byName).orElseGet(DatabaseSelection::undecided);
	}
}

import org.springframework.data.neo4j.repository.Neo4jRepository;
import org.springframework.transaction.annotation.Transactional;

@Transactional(readOnly = true)
interface PersonRepository extends Neo4jRepository<Person, Long> {
}

import org.springframework.data.neo4j.repository.Neo4jRepository;
import org.springframework.data.neo4j.repository.query.Query;
import org.springframework.transaction.annotation.Transactional;

interface PersonRepository extends Neo4jRepository<Person, Long> {

  @Transactional(readOnly = true)
  Person findOneByName(String name); (1)

  @Transactional(readOnly = true)
  @Query("""
    CALL apoc.search.nodeAll('{Person: "name",Movie: ["title","tagline"]}','contains','her')
    YIELD node AS n RETURN n""")
  Person findByCustomQuery(); (2)
}

import java.util.Optional;

import org.springframework.data.neo4j.repository.Neo4jRepository;
import org.springframework.transaction.annotation.Transactional;

interface PersonRepository extends Neo4jRepository<Person, Long> {
}

interface MovieRepository extends Neo4jRepository<Movie, Long> {
  List<Movie> findByLikedByPersonName(String name);
}

public class PersonService {

  private final PersonRepository personRepository;
  private final MovieRepository movieRepository;

  public PersonService(PersonRepository personRepository,
        MovieRepository movieRepository) {
    this.personRepository = personRepository;
    this.movieRepository = movieRepository;
  }

  @Transactional(readOnly = true)
  public Optional<PersonDetails> getPerson(Long id) { (1)
    return this.repository.findById(id)
      .map(person -> {
        var movies = this.movieRepository
          .findByLikedByPersonName(person.getName());
        return new PersonDetails(person, movies);
            });
    }
}

import java.util.Collection;

import org.neo4j.driver.types.Node;
import org.springframework.data.neo4j.core.Neo4jClient;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.TransactionDefinition;
import org.springframework.transaction.support.TransactionTemplate;

public class PersonService {

  private final TransactionTemplate readOnlyTx;

  private final Neo4jClient neo4jClient;

  public PersonService(PlatformTransactionManager transactionManager, Neo4jClient neo4jClient) {

    this.readOnlyTx = new TransactionTemplate(transactionManager, (1)
        new TransactionDefinition() {
          @Override public boolean isReadOnly() {
            return true;
          }
        }
    );
    this.neo4jClient = neo4jClient;
  }

  void internalOperation() { (2)

    Collection<Node> nodes = this.readOnlyTx.execute(state -> {
      return neo4jClient.query("MATCH (n) RETURN n").fetchAs(Node.class) (3)
          .mappedBy((types, record) -> record.get(0).asNode())
          .all();
    });
  }
}

import java.util.Set;

import org.neo4j.driver.Bookmark;
import org.springframework.context.ApplicationListener;

public final class BookmarkCapture
    implements ApplicationListener<Neo4jBookmarksUpdatedEvent> {

    @Override
    public void onApplicationEvent(Neo4jBookmarksUpdatedEvent event) {
        // We make sure that this event is called only once,
        // the thread safe application of those bookmarks is up to your system.
        Set<Bookmark> latestBookmarks = event.getBookmarks();
    }
}

import java.util.Set;
import java.util.function.Supplier;

import org.neo4j.driver.Bookmark;
import org.neo4j.driver.Driver;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.neo4j.core.DatabaseSelectionProvider;
import org.springframework.data.neo4j.core.transaction.Neo4jBookmarkManager;
import org.springframework.data.neo4j.core.transaction.Neo4jTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;

@Configuration
public class BookmarkSeedingConfig {

    @Bean
    public PlatformTransactionManager transactionManager(
            Driver driver, DatabaseSelectionProvider databaseNameProvider) { (1)

        Supplier<Set<Bookmark>> bookmarkSupplier = () -> { (2)
            Bookmark a = null;
            Bookmark b = null;
            return Set.of(a, b);
        };

        Neo4jBookmarkManager bookmarkManager =
            Neo4jBookmarkManager.create(bookmarkSupplier); (3)
        return new Neo4jTransactionManager(
            driver, databaseNameProvider, bookmarkManager); (4)
    }
}

import org.neo4j.driver.Driver;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.neo4j.core.transaction.Neo4jBookmarkManager;

@Configuration
public class BookmarksDisabledConfig {

    @Bean
    public Neo4jBookmarkManager neo4jBookmarkManager() {

        return Neo4jBookmarkManager.noop();
    }
}

interface DomainResults {

    @Transactional(readOnly = true)
    List<MovieEntity> findMoviesAlongShortestPath(PersonEntity from, PersonEntity to);
}

import static org.neo4j.cypherdsl.core.Cypher.anyNode;
import static org.neo4j.cypherdsl.core.Cypher.listWith;
import static org.neo4j.cypherdsl.core.Cypher.name;
import static org.neo4j.cypherdsl.core.Cypher.node;
import static org.neo4j.cypherdsl.core.Cypher.parameter;
import static org.neo4j.cypherdsl.core.Cypher.shortestPath;

import org.neo4j.cypherdsl.core.Cypher;

class DomainResultsImpl implements DomainResults {

    private final Neo4jTemplate neo4jTemplate; (1)

    DomainResultsImpl(Neo4jTemplate neo4jTemplate) {
        this.neo4jTemplate = neo4jTemplate;
    }

    @Override
    public List<MovieEntity> findMoviesAlongShortestPath(PersonEntity from, PersonEntity to) {

        var p1 = node("Person").withProperties("name", parameter("person1"));
        var p2 = node("Person").withProperties("name", parameter("person2"));
        var shortestPath = shortestPath("p").definedBy(
                p1.relationshipBetween(p2).unbounded()
        );
        var p = shortestPath.getRequiredSymbolicName();
        var statement = Cypher.match(shortestPath)
                .with(p, listWith(name("n"))
                        .in(Cypher.nodes(shortestPath))
                        .where(anyNode().named("n").hasLabels("Movie")).returning().as("mn")
                )
                .unwind(name("mn")).as("m")
                .with(p, name("m"))
                .match(node("Person").named("d")
                        .relationshipTo(anyNode("m"), "DIRECTED").named("r")
                )
                .returning(p, Cypher.collect(name("r")), Cypher.collect(name("d")))
                .build();

        Map<String, Object> parameters = new HashMap<>();
        parameters.put("person1", from.getName());
        parameters.put("person2", to.getName());
        return neo4jTemplate.findAll(statement, parameters, MovieEntity.class); (2)
    }
}

interface NonDomainResults {

    class Result { (1)
        public final String name;

        public final String typeOfRelation;

        Result(String name, String typeOfRelation) {
            this.name = name;
            this.typeOfRelation = typeOfRelation;
        }
    }

    @Transactional(readOnly = true)
    Collection<Result> findRelationsToMovie(MovieEntity movie); (2)
}

class NonDomainResultsImpl implements NonDomainResults {

    private final Neo4jClient neo4jClient; (1)

    NonDomainResultsImpl(Neo4jClient neo4jClient) {
        this.neo4jClient = neo4jClient;
    }

    @Override
    public Collection<Result> findRelationsToMovie(MovieEntity movie) {
        return this.neo4jClient
                .query(""
                       + "MATCH (people:Person)-[relatedTo]-(:Movie {title: $title}) "
                       + "RETURN people.name AS name, "
                       + "       Type(relatedTo) as typeOfRelation"
                ) (2)
                .bind(movie.getTitle()).to("title") (3)
                .fetchAs(Result.class) (4)
                .mappedBy((typeSystem, record) -> new Result(record.get("name").asString(),
                        record.get("typeOfRelation").asString())) (5)
                .all(); (6)
    }
}

import org.neo4j.driver.Driver;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import org.springframework.transaction.annotation.EnableTransactionManagement;

import org.springframework.data.neo4j.config.AbstractNeo4jConfig;
import org.springframework.data.neo4j.core.DatabaseSelectionProvider;
import org.springframework.data.neo4j.repository.config.EnableNeo4jRepositories;

@Configuration
@EnableNeo4jRepositories
@EnableTransactionManagement
class MyConfiguration extends AbstractNeo4jConfig {

    @Override @Bean
    public Driver driver() { (1)
        return GraphDatabase.driver("bolt://127.0.0.1:7687", AuthTokens.basic("neo4j", "secret"));
    }

    @Override
    protected Collection<String> getMappingBasePackages() {
        return Collections.singletonList(Person.class.getPackage().getName());
    }

    @Override @Bean (2)
    protected DatabaseSelectionProvider databaseSelectionProvider() {

        return DatabaseSelectionProvider.createStaticDatabaseSelectionProvider("yourDatabase");
    }
}

import org.neo4j.driver.Driver;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.neo4j.config.AbstractReactiveNeo4jConfig;
import org.springframework.data.neo4j.repository.config.EnableReactiveNeo4jRepositories;
import org.springframework.transaction.annotation.EnableTransactionManagement;

@Configuration
@EnableReactiveNeo4jRepositories
@EnableTransactionManagement
class MyConfiguration extends AbstractReactiveNeo4jConfig {

    @Bean
    @Override
    public Driver driver() {
        return GraphDatabase.driver("bolt://127.0.0.1:7687", AuthTokens.basic("neo4j", "secret"));
    }

    @Override
    protected Collection<String> getMappingBasePackages() {
        return Collections.singletonList(Person.class.getPackage().getName());
    }
}

import javax.enterprise.context.ApplicationScoped;
import javax.enterprise.inject.Disposes;
import javax.enterprise.inject.Produces;

import org.neo4j.driver.AuthTokens;
import org.neo4j.driver.Driver;
import org.neo4j.driver.GraphDatabase;

public class Neo4jConfig {

    @Produces @ApplicationScoped
    public Driver driver() { (1)
        return GraphDatabase
            .driver("bolt://127.0.0.1:7687", AuthTokens.basic("neo4j", "secret"));
    }

    public void close(@Disposes Driver driver) {
        driver.close();
    }

    @Produces @Singleton
    public DatabaseSelectionProvider getDatabaseSelectionProvider() { (2)
        return DatabaseSelectionProvider.createStaticDatabaseSelectionProvider("yourDatabase");
    }
}

import javax.enterprise.inject.se.SeContainer;
import javax.enterprise.inject.se.SeContainerInitializer;

import org.springframework.data.neo4j.config.Neo4jCdiExtension;

public class SomeClass {
    void someMethod() {
        try (SeContainer container = SeContainerInitializer.newInstance()
                .disableDiscovery()
                .addExtensions(Neo4jCdiExtension.class)
                .addBeanClasses(YourDriverFactory.class)
                .addPackages(Package.getPackage("your.domain.package"))
            .initialize()
        ) {
            SomeRepository someRepository = container.select(SomeRepository.class).get();
        }
    }
}