Spring Data Neo4j实体路径映射

Question

match p=(a:fakea)-[*]->(:fakeb) where a.aId = 1
return p;

返回两个路径：

{"start":"http://localhost:8180/db/data/node/593222","nodes":["http://localhost:8180/db/data/node/593222","http://localhost:8180/db/data/node/593223","http://localhost:8180/db/data/node/593224","http://localhost:8180/db/data/node/593225"],"length":3,"relationships":["http://localhost:8180/db/data/relationship/2489542","http://localhost:8180/db/data/relationship/2489543","http://localhost:8180/db/data/relationship/2489544"],"end":"http://localhost:8180/db/data/node/593225"}

{"start":"http://localhost:8180/db/data/node/593222","nodes":["http://localhost:8180/db/data/node/593222","http://localhost:8180/db/data/node/593223","http://localhost:8180/db/data/node/593226","http://localhost:8180/db/data/node/593227"],"length":3,"relationships":["http://localhost:8180/db/data/relationship/2489542","http://localhost:8180/db/data/relationship/2489545","http://localhost:8180/db/data/relationship/2489546"],"end":"http://localhost:8180/db/data/node/593227"}

我尝试了几种不同的映射方式，使用我在这里找到的信息：

Spring数据wth ne04j错误...检索路径时出错

public interface FakeRepository extends GraphRepository<FakeA> {

@Query("match p=(a:fakea)-[*]->(:fakeb) where a.aId = {0} return p;")
public EntityPath<FakeA, FakeB> getTree(Long aId);

public interface FakeRepository extends GraphRepository<FakeAbs> {

@Query("match p=(a:fakea)-[*]->(:fakeb) where a.aId = {0} return p;")
public EntityPath<FakeAbs, FakeAbs> getTree(Long aId);

Result<EntityPath<FakeAbs, FakeAbs>> path = fr.getTree(1l);
EntityPath<FakeAbs, FakeAbs> first = path.iterator().next();
first.endNode();

Null pointer:
Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause

java.lang.NullPointerException: null
    at org.springframework.data.neo4j.support.path.ConvertingEntityPath.endNode(ConvertingEntityPath.java:112)

当我试图检查EntityPath结构的任何其他部分（例如length（））时，我会收到类似的空指针。

如何查询不同深度的树路径结构并将结果映射到正确的节点实体？我特别想要路径中包含的节点。

Answer 1

试试这个

而不是你现在拥有的：

public interface FakeRepository extends GraphRepository<FakeA> {

@Query("match p=(a:fakea)-[*]->(:fakeb) where a.aId = {0} return p;")
public EntityPath<FakeA, FakeB> getTree(Long aId);

使用：

public interface FakeRepository extends GraphRepository<FakeA> {

@Query("start p=node{0} match (p)-[*]->(a:fakea) return a;")
public FakeA getTree(FakeA fakeA);