Question

我可以添加和保存多个SchoolRef，但是在检索（祖先并急切地获取）Education对象然后尝试添加另一个SchoolRef之后会收到错误。这与SDN 2.0.1一起使用，但我也更改了其他内容，包括下面的Repository / Cypher查询，因此我无法将其与升级隔离开来。

@Fetch @RelatedTo(type = "EDUCATION_HAS_SCHOOLREF")
private Set<SchoolRef> schoolRefs = new HashSet<SchoolRef>();

public Education() {
}

public void addSchoolRef(SchoolRef schoolRef) {
    getSchoolRefs().add(schoolRef);
}

存储库：

public interface UserRepository extends GraphRepository<User>, CypherDslRepository<User> {

@Query("start id=node:Identifier(identifier={0}) match id<-[:USER_HAS_IDENTIFIER]-user return user")
public User findById(String id);

堆栈跟踪：

Caused by: java.lang.IllegalArgumentException: Cannot obtain single field value for field 'schoolRef'
    at org.springframework.data.neo4j.fieldaccess.RelatedToSingleFieldAccessorFactory$RelatedToSingleFieldAccessor.getValue(RelatedToSingleFieldAccessorFactory.java:94)
    at org.springframework.data.neo4j.fieldaccess.DefaultEntityState.getValue(DefaultEntityState.java:97)
    at org.springframework.data.neo4j.support.mapping.SourceStateTransmitter.copyEntityStatePropertyValue(SourceStateTransmitter.java:90)
    at org.springframework.data.neo4j.support.mapping.SourceStateTransmitter.access$000(SourceStateTransmitter.java:40)
    at org.springframework.data.neo4j.support.mapping.SourceStateTransmitter$2.doWithAssociation(SourceStateTransmitter.java:61)
    at org.springframework.data.mapping.model.BasicPersistentEntity.doWithAssociations(BasicPersistentEntity.java:207)
    at org.springframework.data.neo4j.support.mapping.SourceStateTransmitter.copyPropertiesFrom(SourceStateTransmitter.java:57)
    at org.springframework.data.neo4j.support.mapping.Neo4jEntityConverterImpl.loadEntity(Neo4jEntityConverterImpl.java:100)
    at org.springframework.data.neo4j.support.mapping.Neo4jEntityConverterImpl.read(Neo4jEntityConverterImpl.java:92)
    at org.springframework.data.neo4j.support.mapping.Neo4jEntityPersister$CachedConverter.read(Neo4jEntityPersister.java:170)
    at org.springframework.data.neo4j.support.mapping.Neo4jEntityPersister.createEntityFromState(Neo4jEntityPersister.java:189)
    at org.springframework.data.neo4j.support.Neo4jTemplate.createEntityFromState(Neo4jTemplate.java:180)
    at org.springframework.data.neo4j.fieldaccess.RelationshipHelper.createEntitySetFromRelationshipEndNodes(RelationshipHelper.java:130)
    at org.springframework.data.neo4j.fieldaccess.RelatedToFieldAccessor.createEntitySetFromRelationshipEndNodes(RelatedToFieldAccessor.java:86)
    at org.springframework.data.neo4j.fieldaccess.RelatedToSingleFieldAccessorFactory$RelatedToSingleFieldAccessor.getValue(RelatedToSingleFieldAccessorFactory.java:76)
    at org.springframework.data.neo4j.fieldaccess.DefaultEntityState.getValue(DefaultEntityState.java:97)
    at org.springframework.data.neo4j.support.mapping.SourceStateTransmitter.copyEntityStatePropertyValue(SourceStateTransmitter.java:90)
    at org.springframework.data.neo4j.support.mapping.SourceStateTransmitter.access$000(SourceStateTransmitter.java:40)
    at org.springframework.data.neo4j.support.mapping.SourceStateTransmitter$2.doWithAssociation(SourceStateTransmitter.java:61)
    at org.springframework.data.mapping.model.BasicPersistentEntity.doWithAssociations(BasicPersistentEntity.java:207)
    at org.springframework.data.neo4j.support.mapping.SourceStateTransmitter.copyPropertiesFrom(SourceStateTransmitter.java:57)
    at org.springframework.data.neo4j.support.mapping.Neo4jEntityConverterImpl.loadEntity(Neo4jEntityConverterImpl.java:100)
    at org.springframework.data.neo4j.support.mapping.Neo4jEntityConverterImpl.read(Neo4jEntityConverterImpl.java:92)
    at org.springframework.data.neo4j.support.mapping.Neo4jEntityPersister$CachedConverter.read(Neo4jEntityPersister.java:170)
    at org.springframework.data.neo4j.support.mapping.Neo4jEntityPersister.createEntityFromState(Neo4jEntityPersister.java:189)
    at org.springframework.data.neo4j.support.mapping.Neo4jEntityPersister.persist(Neo4jEntityPersister.java:244)
    at org.springframework.data.neo4j.support.mapping.Neo4jEntityPersister.persist(Neo4jEntityPersister.java:231)
    at org.springframework.data.neo4j.support.Neo4jTemplate.save(Neo4jTemplate.java:293)
    at org.springframework.data.neo4j.support.Neo4jTemplate.save(Neo4jTemplate.java:287)
    at org.springframework.data.neo4j.fieldaccess.RelationshipHelper.getOrCreateState(RelationshipHelper.java:119)
    at org.springframework.data.neo4j.fieldaccess.RelationshipHelper.createSetOfTargetNodes(RelationshipHelper.java:111)
    at org.springframework.data.neo4j.fieldaccess.RelatedToFieldAccessor.createSetOfTargetNodes(RelatedToFieldAccessor.java:82)
    at org.springframework.data.neo4j.fieldaccess.RelatedToCollectionFieldAccessorFactory$RelatedToCollectionFieldAccessor.setValue(RelatedToCollectionFieldAccessorFactory.java:66)
    at org.springframework.data.neo4j.fieldaccess.ManagedFieldAccessorSet.updateValue(ManagedFieldAccessorSet.java:94)
    at org.springframework.data.neo4j.fieldaccess.ManagedFieldAccessorSet.update(ManagedFieldAccessorSet.java:82)
    at org.springframework.data.neo4j.fieldaccess.ManagedFieldAccessorSet.add(ManagedFieldAccessorSet.java:108)

----编辑：相同的错误，但在不同的情况下..

    School school = new School();
    school = neo4j.repositoryFor(School.class).save(school);

    User user1 = new User("Junit", "1");
    SchoolRef schoolRef1 = new SchoolRef();
    schoolRef1.setSchool(school);
    user1.addSchoolRef(schoolRef1);
    user1 = neo4j.repositoryFor(User.class).save(user1);

    User user2 = new User("Junit", "2");
    SchoolRef schoolRef2 = new SchoolRef();
    schoolRef2.setSchool(school);
    user2.addSchoolRef(schoolRef2);
    user2 = neo4j.repositoryFor(User.class).save(user2);  // <- error here

Answer 1

有时我可能对这个明显的问题视而不见......

就我而言，SchoolRef引用了一所学校，但学校可以有很多schoolRef。我没有错误地实施学校，只有一个参考回到SchoolRef。

我能够创建多个引用单个School的SchoolRef，但是当我尝试获取具有多个引用的School时出现此错误。

Answer 2

我们也遇到了这个问题，但这是由于与同一标签有单独的关系。

SDN 2.1.0 / neo4j 1.8：java.lang.IllegalArgumentException：无法获取字段'schoolRef'的单个字段值

2 个答案: