Spring Data Neo4J存储库findAll（）导致nullpointerexception
我已经制作了一个包含我系统中所有人的简单存储库，一切似乎都运行良好。 我可以根据给定的键和值添加，删除甚至检索单个人，但由于某种原因，我无法直接检索存储在存储库中的所有人。 我试过使用findAll（）方法，它应该返回一个iterable。 然后我尝试迭代迭代并将每个人存储在arraylist中，我希望函数返回。
public List getAllPersons() { Iterable p = personRepository.findAll(); System.out.println("person count: " + personRepository.count()); List persons = new ArrayList(); for (Person person : p) { System.out.println("person"); persons.add(person); } return persons; } 打印行打印“3”，因此存储库不为空，但仍然在下面的错误中得到nullpointerexception。
apr 16, 2014 3:45:54 PM org.apache.catalina.core.StandardWrapperValve invoke SEVERE: Servlet.service() for servlet [bmsapp] in context with path [/bmsapp] threw exception [Request processing failed; nested exception is org.neo4j.graphdb.TransactionFailureException: Failed to mark transaction as rollback only.] with root cause java.lang.NullPointerException at org.neo4j.kernel.TopLevelTransaction.markAsRollbackOnly(TopLevelTransaction.java:93) at org.neo4j.kernel.TopLevelTransaction.failure(TopLevelTransaction.java:86) at org.neo4j.cypher.internal.spi.v2_0.TransactionBoundExecutionContext.close(TransactionBoundExecutionContext.scala:58) at org.neo4j.cypher.internal.compiler.v2_0.spi.DelegatingQueryContext.close(DelegatingQueryContext.scala:32) at org.neo4j.cypher.internal.compiler.v2_0.spi.ExceptionTranslatingQueryContext.org$neo4j$cypher$internal$compiler$v2_0$spi$ExceptionTranslatingQueryContext$$super$close(ExceptionTranslatingQueryContext.scala:34) at org.neo4j.cypher.internal.compiler.v2_0.spi.ExceptionTranslatingQueryContext$$anonfun$close$1.apply$mcV$sp(ExceptionTranslatingQueryContext.scala:34) at org.neo4j.cypher.internal.compiler.v2_0.spi.ExceptionTranslatingQueryContext$$anonfun$close$1.apply(ExceptionTranslatingQueryContext.scala:34) at org.neo4j.cypher.internal.compiler.v2_0.spi.ExceptionTranslatingQueryContext$$anonfun$close$1.apply(ExceptionTranslatingQueryContext.scala:34) at org.neo4j.cypher.internal.compiler.v2_0.spi.ExceptionTranslatingQueryContext.org$neo4j$cypher$internal$compiler$v2_0$spi$ExceptionTranslatingQueryContext$$translateException(ExceptionTranslatingQueryContext.scala:149) at org.neo4j.cypher.internal.compiler.v2_0.spi.ExceptionTranslatingQueryContext.close(ExceptionTranslatingQueryContext.scala:34) at org.neo4j.cypher.internal.compiler.v2_0.ClosingIterator.failIfThrows(ClosingIterator.scala:94) at org.neo4j.cypher.internal.compiler.v2_0.ClosingIterator.next(ClosingIterator.scala:45) at org.neo4j.cypher.internal.compiler.v2_0.PipeExecutionResult.next(PipeExecutionResult.scala:168) at org.neo4j.cypher.internal.compiler.v2_0.PipeExecutionResult.next(PipeExecutionResult.scala:34) at scala.collection.Iterator$$anon$11.next(Iterator.scala:328) at scala.collection.convert.Wrappers$IteratorWrapper.next(Wrappers.scala:30) at org.neo4j.cypher.internal.compiler.v2_0.PipeExecutionResult$$anon$1.next(PipeExecutionResult.scala:76) at org.neo4j.helpers.collection.IteratorWrapper.next(IteratorWrapper.java:47) at org.neo4j.helpers.collection.IteratorWrapper.next(IteratorWrapper.java:47) at bmsapp.repository.NeoPersonDao.getAllPersons(NeoPersonDao.java:33) at bmsapp.service.SimplePersonManager.getPersons(SimplePersonManager.java:32) at bmsapp.web.HelloController.HelloHandler(HelloController.java:45) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:483) at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:175) at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:446) at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:434) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:938) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:870) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:961) at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:852) at javax.servlet.http.HttpServlet.service(HttpServlet.java:621) at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:837) at javax.servlet.http.HttpServlet.service(HttpServlet.java:728) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99) at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:936) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407) at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1004) at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589) at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at java.lang.Thread.run(Thread.java:744)
我已经浪费了几个小时来解决这个问题，但没有运气。 有人可以帮帮我吗？
尝试将personRepository.findAll()标记为@Transactional 。
如果它仍然不起作用，你可以发布你的personRepository.findAll()方法personRepository.findAll() ？
谢谢你的答案！ 我已设法通过添加来解决问题
"
到我的应用程序上下文xml文件。 它现在完美运作！ 但是我仍然不确定这个状态是什么以及为什么我只需要它用于findAll（）方法而不是我使用过的任何其他方法。 （count（），findOne（），findBySchemaPropertyValue（）等）
我尝试了mode =“proxy”并且它对我不起作用，如果您使用非注入事务方法相互调用（ 这里的解释），这应该只会产生影响。
这个’TransactionFailureException’可能与该问题有关： https ： //jira.spring.io/browse/DATAGRAPH-531 。 如果是这种情况，您需要更改
service.findAll()
至：
service.findAll().as(Collection.class)
……它应该消失。