Question

我正在做一个测试电影项目来学习neo4j和SDN，这是我面临的一个问题：

如你所知，电影导演可能是制片人或作家，甚至是演员。在我的 java 类架构中，我有 Person 超类。它有孩子：制片人，导演，演员和作家。所有这些子节点都处于同一级别，因此它们是不兼容的类型。

另一方面，在 neo4j 中，我的节点同时是Producer，Director和Writer。

example of node that has several labels
因此，当我想通过repository.findAll（）方法（或通过Cypher查询的自定义方法）获取所有控制器时，我遇到了问题。春天告诉我：

java.lang.IllegalArgumentException：无法设置java.util.Set字段 com.test.db.domain.Producer.producedMovies to com.test.db.domain.Director

我使用Neo4j 2.0.1和Spring Data Neo4j 3.0.0.RELEASE。

解决此类问题的正确方法是什么？

更新：
这是代码：

public class App {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("service-beans.xml");
        Neo4jTemplate neo4jTemplate = context.getBean(Neo4jTemplate.class);

        DirectorRepository repository = context.getBean(DirectorRepository.class);
        try (Transaction transaction = neo4jTemplate.getGraphDatabase().beginTx()) {
            EndResult<Director> all = repository.findAll_Upd(); //repository.findAll();
            Iterator<Director> iterator = all.iterator();
            while(iterator.hasNext()) {
                System.out.println(iterator.next());
            }
            transaction.success();
        }
    }
}

@Transactional
public interface DirectorRepository extends GraphRepository<Director> {
    @Query("match(n:Director) return n")
    EndResult<Director> findAll_Upd();
}

@NodeEntity
public class Person implements Comparable<Person> {
    @GraphId
    Long nodeId;
//    @Indexed(unique=true)
    String id;
    @Indexed(indexType= IndexType.FULLTEXT, indexName = "people")
    String name;
    private Short born;
    private Date birthday;
    private String birthplace;
    private String biography;
    private Integer version;
    private Date lastModified;
    private String profileImageUrl;
...
}

public class Director extends Person {
    @Fetch @RelatedTo(elementClass = Movie.class, type = RelationshipConstants.DIRECTED)
    private Set<Movie> directedMovies = new HashSet<>();
}

public class Producer extends Person {
    @Fetch @RelatedTo(elementClass = Movie.class, type = RelationshipConstants.PRODUCED)
    private Set<Movie> producedMovies = new HashSet<>();
}

public class Actor extends Person  {
    @RelatedToVia(type = RelationshipConstants.ACTED_IN)
    List<Role> roles;
}

@NodeEntity
public class Movie implements Comparable<Movie> {
    @GraphId
    Long nodeId;    
    @Indexed(unique = true)
    String id;    
    @Indexed(indexType= IndexType.FULLTEXT, indexName = "search")
    String title;    
    int released;    
    String tagline;    
    @Fetch @RelatedTo(type = RelationshipConstants.ACTED_IN, direction = INCOMING)
    Set<Actor> actors;    
    @Fetch @RelatedTo(type = RelationshipConstants.PRODUCED, direction = INCOMING)
    Set<Producer> producers;    
    @RelatedToVia(type = RelationshipConstants.ACTED_IN, direction = INCOMING)
    List<Role> roles;
}

完整的例外：

线程中的异常＆＃34; main＆＃34; org.springframework.data.mapping.model.MappingException：设置属性在Rob Reiner [null]上生成的电影为null org.springframework.data.neo4j.support.mapping.SourceStateTransmitter.setProperty（SourceStateTransmitter.java:85）在 org.springframework.data.neo4j.support.mapping.SourceStateTransmitter.copyEntityStatePropertyValue（SourceStateTransmitter.java:91）在 org.springframework.data.neo4j.support.mapping.SourceStateTransmitter.access $ 000（SourceStateTransmitter.java:40）在 org.springframework.data.neo4j.support.mapping.SourceStateTransmitter $ 2.doWithAssociation（SourceStateTransmitter.java:61）在 org.springframework.data.mapping.model.BasicPersistentEntity.doWithAssociations（BasicPersistentEntity.java:291）在 org.springframework.data.neo4j.support.mapping.SourceStateTransmitter.copyPropertiesFrom（SourceStateTransmitter.java:57）在 org.springframework.data.neo4j.support.mapping.Neo4jEntityFetchHandler.fetchValue（Neo4jEntityFetchHandler.java:75）在 org.springframework.data.neo4j.support.mapping.Neo4jEntityFetchHandler.fetch（Neo4jEntityFetchHandler.java:60）在 org.springframework.data.neo4j.support.mapping.Neo4jEntityConverterImpl $ 1.doWithAssociation（Neo4jEntityConverterImpl.java:135）在 org.springframework.data.mapping.model.BasicPersistentEntity.doWithAssociations（BasicPersistentEntity.java:291）在 org.springframework.data.neo4j.support.mapping.Neo4jEntityConverterImpl.cascadeFetch（Neo4jEntityConverterImpl.java:125）在 org.springframework.data.neo4j.support.mapping.Neo4jEntityConverterImpl.loadEntity（Neo4jEntityConverterImpl.java:114）在 org.springframework.data.neo4j.support.mapping.Neo4jEntityConverterImpl.read（Neo4jEntityConverterImpl.java:104）在 org.springframework.data.neo4j.support.mapping.Neo4jEntityPersister $ CachedConverter.read（Neo4jEntityPersister.java:170）在 org.springframework.data.neo4j.support.mapping.Neo4jEntityPersister.createEntityFromState（Neo4jEntityPersister.java:189）在 org.springframework.data.neo4j.support.Neo4jTemplate.createEntityFromState（Neo4jTemplate.java:223）在 org.springframework.data.neo4j.fieldaccess.RelationshipHelper.createEntitySetFromRelationshipEndNodes（RelationshipHelper.java:150）在 org.springframework.data.neo4j.fieldaccess.RelatedToFieldAccessor.createEntitySetFromRelationshipEndNodes（RelatedToFieldAccessor.java:86）在 org.springframework.data.neo4j.fieldaccess.RelatedToCollectionFieldAccessorFactory $ RelatedToCollectionFieldAccessor.getValue（RelatedToCollectionFieldAccessorFactory.java:76）在 org.springframework.data.neo4j.fieldaccess.DefaultEntityState.getValue（DefaultEntityState.java:97）在 org.springframework.data.neo4j.support.mapping.SourceStateTransmitter.copyEntityStatePropertyValue（SourceStateTransmitter.java:90）在 org.springframework.data.neo4j.support.mapping.SourceStateTransmitter.access $ 000（SourceStateTransmitter.java:40）在 org.springframework.data.neo4j.support.mapping.SourceStateTransmitter $ 2.doWithAssociation（SourceStateTransmitter.java:61）在 org.springframework.data.mapping.model.BasicPersistentEntity.doWithAssociations（BasicPersistentEntity.java:291）在 org.springframework.data.neo4j.support.mapping.SourceStateTransmitter.copyPropertiesFrom（SourceStateTransmitter.java:57）在 org.springframework.data.neo4j.support.mapping.Neo4jEntityConverterImpl.loadEntity（Neo4jEntityConverterImpl.java:112）在 org.springframework.data.neo4j.support.mapping.Neo4jEntityConverterImpl.read（Neo4jEntityConverterImpl.java:104）在 org.springframework.data.neo4j.support.mapping.Neo4jEntityPersister $ CachedConverter.read（Neo4jEntityPersister.java:170）在 org.springframework.data.neo4j.support.mapping.Neo4jEntityPersister.createEntityFromState（Neo4jEntityPersister.java:189）在 org.springframework.data.neo4j.support.mapping.Neo4jEntityPersister.projectTo（Neo4jEntityPersister.java:216）在 org.springframework.data.neo4j.support.Neo4jTemplate.projectTo（Neo4jTemplate.java:240）在 org.springframework.data.neo4j.support.conversion.EntityResultConverter.doConvert（EntityResultConverter.java:73）在 org.springframework.data.neo4j.conversion.DefaultConverter.convert（DefaultConverter.java:44）在 org.springframework.data.neo4j.support.conversion.EntityResultConverter.convert（EntityResultConverter.java:165）在 org.springframework.data.neo4j.conversion.QueryResultBuilder $ 1.Convert的（QueryResultBuilder.java:103）在 org.springframework.data.neo4j.conversion.QueryResultBuilder $ 1.访问$ 300（QueryResultBuilder.java:81）在 org.springframework.data.neo4j.conversion.QueryResultBuilder $ 1 $ 1.underlyingObjectToObject（QueryResultBuilder.java:121）在 org.neo4j.helpers.collection.IteratorWrapper.next（IteratorWrapper.java:47）在com.test.util.App.main（App.java:34）at sun.reflect.NativeMethodAccessorImpl.invoke0（Native Method）at sun.reflect.NativeMethodAccessorImpl.invoke（NativeMethodAccessorImpl.java:57）在 sun.reflect.DelegatingMethodAccessorImpl.invoke（DelegatingMethodAccessorImpl.java:43）在java.lang.reflect.Method.invoke（Method.java:606）at com.intellij.rt.execution.application.AppMain.main（AppMain.java:120）引起：java.lang.IllegalArgumentException：无法设置 java.util.Set字段com.test.db.domain.Producer.producedMovies到 com.test.db.domain.Director at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException（UnsafeFieldAccessorImpl.java:164）在 sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException（UnsafeFieldAccessorImpl.java:168）在 sun.reflect.UnsafeFieldAccessorImpl.ensureObj（UnsafeFieldAccessorImpl.java:55）在 sun.reflect.UnsafeObjectFieldAccessorImpl.set（UnsafeObjectFieldAccessorImpl.java:75）在java.lang.reflect.Field.set（Field.java:741）at org.springframework.util.ReflectionUtils.setField（ReflectionUtils.java:102）在 org.springframework.data.mapping.model.BeanWrapper.setProperty（BeanWrapper.java:90）在 org.springframework.data.mapping.model.BeanWrapper.setProperty（BeanWrapper.java:68）在 org.springframework.data.neo4j.support.mapping.SourceStateTransmitter.setProperty（SourceStateTransmitter.java:83） ... 43更多

更新
我也尝试过projectTo（）方法（projections），但我仍然得到同样的异常：

Director director = neo4jTemplate.projectTo(person, Director.class);

Answer 1

我不确定neo4j映射 - 但您的java模型与您的业务描述不匹配 - 您更需要具有Set＆lt;的Person类。 MovieJob＆GT;成员 - 其中MovieJob是您的抽象类，其中Actor，Director，Producer是子类。

如何使节点成为多种类型？

1 个答案: