在抽象超类中使用@Id @GeneratedValue 时出现 Neo4j OGM NullPointerException
Neo4j OGM NullPointerException when using @Id @GeneratedValue in abstract superclass
我正在尝试保存一个域对象，该域对象继承了其 id，并从 superclass@Id @GeneratedValue(strategy = UuidStrategy.class) 注释]，但是当我尝试保存时得到 NullPointerException，即使 Neo4j OGM manual 声明这是可能的（并且推荐）。 （注意，如果我把id移到非抽象的sub-class，节点就愉快地保存了）。
代码使用SpringBoot 2.0.0.M7
编辑 #2： 如果我现在使抽象 classes 具体化（通过删除 abstract 关键字），节点现在将填充到数据库中。但是，如果没有abstract 关键字，super-class 的标签也将应用于节点（即节点具有标签Fan、BaseNodeEntity 和BaseEntity）。这可能是该问题的（临时？）解决方法，尽管我不知道将这些额外标签应用于所有节点的影响。 （有人知道吗？）或者谁能提供更好的解决方案？
编辑 #1 我已经将摘要 classes 移动到与其他节点相同的包中，以便根据设置正确扫描它们SessionFactory（对于包 "com.ideafan.server.neo4j.node"）但是我现在得到一个 UnsatisfiedDependencyError 如下：
2018-02-04 17:33:01.498 ERROR 15908 --- [ main] o.s.boot.SpringApplication : Application startup failed
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'dataPopulatorService': Unsatisfied dependency expressed through field 'fanRepository'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'fanRepository': Unsatisfied dependency expressed through method 'setSession' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.data.neo4j.transaction.SharedSessionCreator#0': Cannot resolve reference to bean 'sessionFactory' while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory' defined in class path resource [com/ideafan/server/PersistenceContext.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.neo4j.ogm.session.SessionFactory]: Factory method 'sessionFactory' threw exception; nested exception is java.lang.NullPointerException
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:586) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:91) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:372) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1344) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:582) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:502) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean[=10=](AbstractBeanFactory.java:312) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:310) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:200) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:758) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:868) ~[spring-context-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:549) ~[spring-context-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:138) ~[spring-boot-2.0.0.M7.jar:2.0.0.M7]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:751) [spring-boot-2.0.0.M7.jar:2.0.0.M7]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:387) [spring-boot-2.0.0.M7.jar:2.0.0.M7]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:327) [spring-boot-2.0.0.M7.jar:2.0.0.M7]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1245) [spring-boot-2.0.0.M7.jar:2.0.0.M7]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1233) [spring-boot-2.0.0.M7.jar:2.0.0.M7]
at com.ideafan.server.IdeaFanServerApplication.main(IdeaFanServerApplication.java:14) [classes/:na]
Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'fanRepository': Unsatisfied dependency expressed through method 'setSession' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.data.neo4j.transaction.SharedSessionCreator#0': Cannot resolve reference to bean 'sessionFactory' while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory' defined in class path resource [com/ideafan/server/PersistenceContext.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.neo4j.ogm.session.SessionFactory]: Factory method 'sessionFactory' threw exception; nested exception is java.lang.NullPointerException
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredMethodElement.inject(AutowiredAnnotationBeanPostProcessor.java:667) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:91) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:372) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1344) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:582) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:502) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean[=10=](AbstractBeanFactory.java:312) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:310) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:200) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:251) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1135) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1062) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:583) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
... 19 common frames omitted
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.data.neo4j.transaction.SharedSessionCreator#0': Cannot resolve reference to bean 'sessionFactory' while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory' defined in class path resource [com/ideafan/server/PersistenceContext.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.neo4j.ogm.session.SessionFactory]: Factory method 'sessionFactory' threw exception; nested exception is java.lang.NullPointerException
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:378) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:110) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.resolveConstructorArguments(ConstructorResolver.java:622) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:440) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1250) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1099) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:545) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:502) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean[=10=](AbstractBeanFactory.java:312) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:310) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:200) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:251) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1135) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1062) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredMethodElement.inject(AutowiredAnnotationBeanPostProcessor.java:659) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
... 32 common frames omitted
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory' defined in class path resource [com/ideafan/server/PersistenceContext.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.neo4j.ogm.session.SessionFactory]: Factory method 'sessionFactory' threw exception; nested exception is java.lang.NullPointerException
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:587) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1250) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1099) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:545) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:502) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean[=10=](AbstractBeanFactory.java:312) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:310) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:200) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:367) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
... 47 common frames omitted
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.neo4j.ogm.session.SessionFactory]: Factory method 'sessionFactory' threw exception; nested exception is java.lang.NullPointerException
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:579) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
... 56 common frames omitted
Caused by: java.lang.NullPointerException: null
at org.neo4j.ogm.autoindex.AutoIndex.<init>(AutoIndex.java:39) ~[neo4j-ogm-core-3.0.2.jar:na]
at org.neo4j.ogm.autoindex.AutoIndexManager.initialiseIndexMetadata(AutoIndexManager.java:74) ~[neo4j-ogm-core-3.0.2.jar:na]
at org.neo4j.ogm.autoindex.AutoIndexManager.<init>(AutoIndexManager.java:59) ~[neo4j-ogm-core-3.0.2.jar:na]
at org.neo4j.ogm.session.SessionFactory.<init>(SessionFactory.java:83) ~[neo4j-ogm-core-3.0.2.jar:na]
at com.ideafan.server.PersistenceContext.sessionFactory(PersistenceContext.java:27) ~[classes/:na]
at com.ideafan.server.PersistenceContext$$EnhancerBySpringCGLIB$$a83ca23f.CGLIB$sessionFactory(<generated>) ~[classes/:na]
at com.ideafan.server.PersistenceContext$$EnhancerBySpringCGLIB$$a83ca23f$$FastClassBySpringCGLIB$bf83868.invoke(<generated>) ~[classes/:na]
at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:228) ~[spring-core-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:361) ~[spring-context-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at com.ideafan.server.PersistenceContext$$EnhancerBySpringCGLIB$$a83ca23f.sessionFactory(<generated>) ~[classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_101]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_101]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_101]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_101]
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
... 57 common frames omitted
域classes:
Fan.java
package com.ideafan.server.neo4j.node;
import org.neo4j.ogm.annotation.NodeEntity;
import com.ideafan.server.neo4j.BaseNodeEntity;
@NodeEntity
public class Fan extends BaseNodeEntity {
String firstName;
public Fan() {}
public Fan(String firstName) {
super();
this.firstName = firstName;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
}
BaseNodeEntity.java
public abstract class BaseNodeEntity extends BaseEntity {
}
BaseEntity.java
package com.ideafan.server.neo4j;
import org.neo4j.ogm.annotation.GeneratedValue;
import org.neo4j.ogm.annotation.Id;
import org.neo4j.ogm.id.UuidStrategy;
public abstract class BaseEntity {
@Id @GeneratedValue(strategy = UuidStrategy.class)
private String uuid;
}
FanRepository.java
@Repository
public interface FanRepository extends Neo4jRepository<Fan, String> {
Fan findByFirstName(String firstName);
}
业务逻辑classes:
IdeaFanServerApplication.java
@SpringBootApplication
public class IdeaFanServerApplication {
public static void main(String[] args) {
ApplicationContext applicationContext = SpringApplication.run(IdeaFanServerApplication.class, args);
DataPopulatorService dataPopulatorService = applicationContext.getBean(DataPopulatorService.class);
dataPopulatorService.populateSampleData();
}
}
DataPopulatorService.java
@Service
@Transactional
public class DataPopulatorService {
private Logger logger = LogManager.getLogger();
@Autowired private FanRepository fanRepository;
public void populateSampleData() {
Fan fan = new Fan("Fan");
fanRepository.save(fan);
}
}
配置：
AppConfig.java
@Configuration
@ComponentScan({"com.ideafan.server.controller"})
public class AppConfig {
@Bean
public DataPopulatorService dataPopulatorService() {
return new DataPopulatorService();
}
}
PersistenceContext.java
@Configuration
@ComponentScan("com.ideafan.server.neo4j")
@EnableNeo4jRepositories(basePackages = "com.ideafan.server.neo4j.repository")
@EnableTransactionManagement
public class PersistenceContext {
@Bean
public SessionFactory sessionFactory() {
// with domain entity base package(s)
return new SessionFactory(configuration(), "com.ideafan.server.neo4j.node");
}
@Bean
public org.neo4j.ogm.config.Configuration configuration() {
// Configuration reference: https://neo4j.com/docs/ogm-manual/current/reference/#reference:configuration
org.neo4j.ogm.config.Configuration configuration = new org.neo4j.ogm.config.Configuration.Builder()
.uri("bolt://neo4j:password@localhost") // Note: neo4j is the username and password is the password.
.build();
return configuration;
}
@Bean
public Neo4jTransactionManager transactionManager() throws Exception {
return new Neo4jTransactionManager(sessionFactory());
}
}
日志（有错误）：
2018-02-04 16:34:49.207 INFO 11112 --- [ main] c.i.server.IdeaFanServerApplication : Started IdeaFanServerApplication in 4.531 seconds (JVM running for 5.55)
Exception in thread "main" java.lang.NullPointerException
at org.neo4j.ogm.context.MappingContext.nativeId(MappingContext.java:478)
at org.neo4j.ogm.context.EntityGraphMapper.getNodeBuilder(EntityGraphMapper.java:278)
at org.neo4j.ogm.context.EntityGraphMapper.mapEntity(EntityGraphMapper.java:216)
at org.neo4j.ogm.context.EntityGraphMapper.map(EntityGraphMapper.java:127)
at org.neo4j.ogm.session.delegates.SaveDelegate.save(SaveDelegate.java:80)
at org.neo4j.ogm.session.delegates.SaveDelegate.save(SaveDelegate.java:41)
at org.neo4j.ogm.session.Neo4jSession.save(Neo4jSession.java:451)
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:498)
at org.springframework.data.neo4j.transaction.SharedSessionCreator$SharedSessionInvocationHandler.invoke(SharedSessionCreator.java:131)
at com.sun.proxy.$Proxy64.save(Unknown Source)
at org.springframework.data.neo4j.repository.support.SimpleNeo4jRepository.save(SimpleNeo4jRepository.java:73)
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:498)
at org.springframework.data.repository.core.support.RepositoryComposition$RepositoryFragments.invoke(RepositoryComposition.java:377)
at org.springframework.data.repository.core.support.RepositoryComposition.invoke(RepositoryComposition.java:200)
at org.springframework.data.repository.core.support.RepositoryFactorySupport$ImplementationMethodExecutionInterceptor.invoke(RepositoryFactorySupport.java:636)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.doInvoke(RepositoryFactorySupport.java:600)
at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:580)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:59)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:294)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:98)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:139)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
at org.springframework.data.repository.core.support.SurroundingTransactionDetectorMethodInterceptor.invoke(SurroundingTransactionDetectorMethodInterceptor.java:61)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212)
at com.sun.proxy.$Proxy70.save(Unknown Source)
at com.ideafan.server.service.admin.datapopulator.DataPopulatorService.populateSampleData(DataPopulatorService.java:25)
at com.ideafan.server.service.admin.datapopulator.DataPopulatorService$$FastClassBySpringCGLIB$$dd77d09f.invoke(<generated>)
at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:747)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163)
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:294)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:98)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:689)
at com.ideafan.server.service.admin.datapopulator.DataPopulatorService$$EnhancerBySpringCGLIB$85cb29.populateSampleData(<generated>)
at com.ideafan.server.IdeaFanServerApplication.main(IdeaFanServerApplication.java:18)
当使用没有 id 的实体时，显然会发生错误 as per this issue on the ogm issue-tracker.
如果我不是将 @Id @GeneratedValue id 字段放在抽象的超级 class 中，而是将它放在具体的子 class 中，那么节点将被写入数据库没问题。
修改域class:
Fan.java
包裹 com.ideafan.server.neo4j.node;
import org.neo4j.ogm.annotation.GeneratedValue;
import org.neo4j.ogm.annotation.Id;
import org.neo4j.ogm.annotation.NodeEntity;
import org.neo4j.ogm.id.UuidStrategy;
@NodeEntity
public class Fan /*extends BaseNodeEntity*/ {
@Id @GeneratedValue(strategy = UuidStrategy.class)
private String id;
String firstName;
public Fan() {}
public Fan(String firstName) {
super();
this.firstName = firstName;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
}
日志（无错误）：
2018-02-04 16:10:25.373 INFO 11892 --- [ main] c.i.server.IdeaFanServerApplication : Started IdeaFanServerApplication in 4.952 seconds (JVM running for 5.751)
2018-02-04 16:10:25.842 INFO 11892 --- [ main] o.n.o.drivers.bolt.request.BoltRequest : Request: UNWIND {rows} as row MERGE (n:`Fan`{id: row.props.id}) SET n=row.props RETURN row.nodeRef as ref, ID(n) as id, row.type as type with params {rows=[{nodeRef=-1, type=node, props={firstName=Fan, id=45a22c54-27a0-47af-bb8e-f4b9d3195d94}}]}
谁能看出问题出在哪里？
所有节点 classes 应该在同一个包中以便被扫描，尝试将所有 classes 移动到与 class Fan 相同的包中。简而言之，在这个包中：
new SessionFactory(configuration(), "com.ideafan.server.neo4j.node");
更新：在将 @Id 字段放入基本摘要 class 时，请确保根据 this discussion 用 @NodeEntity 注释基本摘要 class。
我正在尝试保存一个域对象，该域对象继承了其 id，并从 superclass@Id @GeneratedValue(strategy = UuidStrategy.class) 注释]，但是当我尝试保存时得到 NullPointerException，即使 Neo4j OGM manual 声明这是可能的（并且推荐）。 （注意，如果我把id移到非抽象的sub-class，节点就愉快地保存了）。
代码使用SpringBoot 2.0.0.M7
编辑 #2： 如果我现在使抽象 classes 具体化（通过删除 abstract 关键字），节点现在将填充到数据库中。但是，如果没有abstract 关键字，super-class 的标签也将应用于节点（即节点具有标签Fan、BaseNodeEntity 和BaseEntity）。这可能是该问题的（临时？）解决方法，尽管我不知道将这些额外标签应用于所有节点的影响。 （有人知道吗？）或者谁能提供更好的解决方案？
编辑 #1 我已经将摘要 classes 移动到与其他节点相同的包中，以便根据设置正确扫描它们SessionFactory（对于包 "com.ideafan.server.neo4j.node"）但是我现在得到一个 UnsatisfiedDependencyError 如下：
2018-02-04 17:33:01.498 ERROR 15908 --- [ main] o.s.boot.SpringApplication : Application startup failed
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'dataPopulatorService': Unsatisfied dependency expressed through field 'fanRepository'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'fanRepository': Unsatisfied dependency expressed through method 'setSession' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.data.neo4j.transaction.SharedSessionCreator#0': Cannot resolve reference to bean 'sessionFactory' while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory' defined in class path resource [com/ideafan/server/PersistenceContext.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.neo4j.ogm.session.SessionFactory]: Factory method 'sessionFactory' threw exception; nested exception is java.lang.NullPointerException
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:586) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:91) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:372) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1344) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:582) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:502) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean[=10=](AbstractBeanFactory.java:312) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:310) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:200) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:758) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:868) ~[spring-context-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:549) ~[spring-context-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:138) ~[spring-boot-2.0.0.M7.jar:2.0.0.M7]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:751) [spring-boot-2.0.0.M7.jar:2.0.0.M7]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:387) [spring-boot-2.0.0.M7.jar:2.0.0.M7]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:327) [spring-boot-2.0.0.M7.jar:2.0.0.M7]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1245) [spring-boot-2.0.0.M7.jar:2.0.0.M7]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1233) [spring-boot-2.0.0.M7.jar:2.0.0.M7]
at com.ideafan.server.IdeaFanServerApplication.main(IdeaFanServerApplication.java:14) [classes/:na]
Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'fanRepository': Unsatisfied dependency expressed through method 'setSession' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.data.neo4j.transaction.SharedSessionCreator#0': Cannot resolve reference to bean 'sessionFactory' while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory' defined in class path resource [com/ideafan/server/PersistenceContext.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.neo4j.ogm.session.SessionFactory]: Factory method 'sessionFactory' threw exception; nested exception is java.lang.NullPointerException
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredMethodElement.inject(AutowiredAnnotationBeanPostProcessor.java:667) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:91) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:372) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1344) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:582) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:502) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean[=10=](AbstractBeanFactory.java:312) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:310) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:200) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:251) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1135) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1062) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:583) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
... 19 common frames omitted
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.data.neo4j.transaction.SharedSessionCreator#0': Cannot resolve reference to bean 'sessionFactory' while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory' defined in class path resource [com/ideafan/server/PersistenceContext.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.neo4j.ogm.session.SessionFactory]: Factory method 'sessionFactory' threw exception; nested exception is java.lang.NullPointerException
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:378) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:110) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.resolveConstructorArguments(ConstructorResolver.java:622) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:440) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1250) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1099) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:545) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:502) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean[=10=](AbstractBeanFactory.java:312) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:310) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:200) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:251) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1135) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1062) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredMethodElement.inject(AutowiredAnnotationBeanPostProcessor.java:659) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
... 32 common frames omitted
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory' defined in class path resource [com/ideafan/server/PersistenceContext.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.neo4j.ogm.session.SessionFactory]: Factory method 'sessionFactory' threw exception; nested exception is java.lang.NullPointerException
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:587) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1250) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1099) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:545) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:502) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean[=10=](AbstractBeanFactory.java:312) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:310) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:200) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:367) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
... 47 common frames omitted
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.neo4j.ogm.session.SessionFactory]: Factory method 'sessionFactory' threw exception; nested exception is java.lang.NullPointerException
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:579) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
... 56 common frames omitted
Caused by: java.lang.NullPointerException: null
at org.neo4j.ogm.autoindex.AutoIndex.<init>(AutoIndex.java:39) ~[neo4j-ogm-core-3.0.2.jar:na]
at org.neo4j.ogm.autoindex.AutoIndexManager.initialiseIndexMetadata(AutoIndexManager.java:74) ~[neo4j-ogm-core-3.0.2.jar:na]
at org.neo4j.ogm.autoindex.AutoIndexManager.<init>(AutoIndexManager.java:59) ~[neo4j-ogm-core-3.0.2.jar:na]
at org.neo4j.ogm.session.SessionFactory.<init>(SessionFactory.java:83) ~[neo4j-ogm-core-3.0.2.jar:na]
at com.ideafan.server.PersistenceContext.sessionFactory(PersistenceContext.java:27) ~[classes/:na]
at com.ideafan.server.PersistenceContext$$EnhancerBySpringCGLIB$$a83ca23f.CGLIB$sessionFactory(<generated>) ~[classes/:na]
at com.ideafan.server.PersistenceContext$$EnhancerBySpringCGLIB$$a83ca23f$$FastClassBySpringCGLIB$bf83868.invoke(<generated>) ~[classes/:na]
at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:228) ~[spring-core-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:361) ~[spring-context-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at com.ideafan.server.PersistenceContext$$EnhancerBySpringCGLIB$$a83ca23f.sessionFactory(<generated>) ~[classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_101]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_101]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_101]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_101]
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154) ~[spring-beans-5.0.2.RELEASE.jar:5.0.2.RELEASE]
... 57 common frames omitted
域classes:
Fan.java
package com.ideafan.server.neo4j.node;
import org.neo4j.ogm.annotation.NodeEntity;
import com.ideafan.server.neo4j.BaseNodeEntity;
@NodeEntity
public class Fan extends BaseNodeEntity {
String firstName;
public Fan() {}
public Fan(String firstName) {
super();
this.firstName = firstName;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
}
BaseNodeEntity.java
public abstract class BaseNodeEntity extends BaseEntity {
}
BaseEntity.java
package com.ideafan.server.neo4j;
import org.neo4j.ogm.annotation.GeneratedValue;
import org.neo4j.ogm.annotation.Id;
import org.neo4j.ogm.id.UuidStrategy;
public abstract class BaseEntity {
@Id @GeneratedValue(strategy = UuidStrategy.class)
private String uuid;
}
FanRepository.java
@Repository
public interface FanRepository extends Neo4jRepository<Fan, String> {
Fan findByFirstName(String firstName);
}
业务逻辑classes:
IdeaFanServerApplication.java
@SpringBootApplication
public class IdeaFanServerApplication {
public static void main(String[] args) {
ApplicationContext applicationContext = SpringApplication.run(IdeaFanServerApplication.class, args);
DataPopulatorService dataPopulatorService = applicationContext.getBean(DataPopulatorService.class);
dataPopulatorService.populateSampleData();
}
}
DataPopulatorService.java
@Service
@Transactional
public class DataPopulatorService {
private Logger logger = LogManager.getLogger();
@Autowired private FanRepository fanRepository;
public void populateSampleData() {
Fan fan = new Fan("Fan");
fanRepository.save(fan);
}
}
配置：
AppConfig.java
@Configuration
@ComponentScan({"com.ideafan.server.controller"})
public class AppConfig {
@Bean
public DataPopulatorService dataPopulatorService() {
return new DataPopulatorService();
}
}
PersistenceContext.java
@Configuration
@ComponentScan("com.ideafan.server.neo4j")
@EnableNeo4jRepositories(basePackages = "com.ideafan.server.neo4j.repository")
@EnableTransactionManagement
public class PersistenceContext {
@Bean
public SessionFactory sessionFactory() {
// with domain entity base package(s)
return new SessionFactory(configuration(), "com.ideafan.server.neo4j.node");
}
@Bean
public org.neo4j.ogm.config.Configuration configuration() {
// Configuration reference: https://neo4j.com/docs/ogm-manual/current/reference/#reference:configuration
org.neo4j.ogm.config.Configuration configuration = new org.neo4j.ogm.config.Configuration.Builder()
.uri("bolt://neo4j:password@localhost") // Note: neo4j is the username and password is the password.
.build();
return configuration;
}
@Bean
public Neo4jTransactionManager transactionManager() throws Exception {
return new Neo4jTransactionManager(sessionFactory());
}
}
日志（有错误）：
2018-02-04 16:34:49.207 INFO 11112 --- [ main] c.i.server.IdeaFanServerApplication : Started IdeaFanServerApplication in 4.531 seconds (JVM running for 5.55)
Exception in thread "main" java.lang.NullPointerException
at org.neo4j.ogm.context.MappingContext.nativeId(MappingContext.java:478)
at org.neo4j.ogm.context.EntityGraphMapper.getNodeBuilder(EntityGraphMapper.java:278)
at org.neo4j.ogm.context.EntityGraphMapper.mapEntity(EntityGraphMapper.java:216)
at org.neo4j.ogm.context.EntityGraphMapper.map(EntityGraphMapper.java:127)
at org.neo4j.ogm.session.delegates.SaveDelegate.save(SaveDelegate.java:80)
at org.neo4j.ogm.session.delegates.SaveDelegate.save(SaveDelegate.java:41)
at org.neo4j.ogm.session.Neo4jSession.save(Neo4jSession.java:451)
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:498)
at org.springframework.data.neo4j.transaction.SharedSessionCreator$SharedSessionInvocationHandler.invoke(SharedSessionCreator.java:131)
at com.sun.proxy.$Proxy64.save(Unknown Source)
at org.springframework.data.neo4j.repository.support.SimpleNeo4jRepository.save(SimpleNeo4jRepository.java:73)
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:498)
at org.springframework.data.repository.core.support.RepositoryComposition$RepositoryFragments.invoke(RepositoryComposition.java:377)
at org.springframework.data.repository.core.support.RepositoryComposition.invoke(RepositoryComposition.java:200)
at org.springframework.data.repository.core.support.RepositoryFactorySupport$ImplementationMethodExecutionInterceptor.invoke(RepositoryFactorySupport.java:636)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.doInvoke(RepositoryFactorySupport.java:600)
at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:580)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:59)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:294)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:98)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:139)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
at org.springframework.data.repository.core.support.SurroundingTransactionDetectorMethodInterceptor.invoke(SurroundingTransactionDetectorMethodInterceptor.java:61)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212)
at com.sun.proxy.$Proxy70.save(Unknown Source)
at com.ideafan.server.service.admin.datapopulator.DataPopulatorService.populateSampleData(DataPopulatorService.java:25)
at com.ideafan.server.service.admin.datapopulator.DataPopulatorService$$FastClassBySpringCGLIB$$dd77d09f.invoke(<generated>)
at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:747)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163)
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:294)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:98)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:689)
at com.ideafan.server.service.admin.datapopulator.DataPopulatorService$$EnhancerBySpringCGLIB$85cb29.populateSampleData(<generated>)
at com.ideafan.server.IdeaFanServerApplication.main(IdeaFanServerApplication.java:18)
当使用没有 id 的实体时，显然会发生错误 as per this issue on the ogm issue-tracker.
如果我不是将 @Id @GeneratedValue id 字段放在抽象的超级 class 中，而是将它放在具体的子 class 中，那么节点将被写入数据库没问题。
修改域class:
Fan.java 包裹 com.ideafan.server.neo4j.node;
import org.neo4j.ogm.annotation.GeneratedValue;
import org.neo4j.ogm.annotation.Id;
import org.neo4j.ogm.annotation.NodeEntity;
import org.neo4j.ogm.id.UuidStrategy;
@NodeEntity
public class Fan /*extends BaseNodeEntity*/ {
@Id @GeneratedValue(strategy = UuidStrategy.class)
private String id;
String firstName;
public Fan() {}
public Fan(String firstName) {
super();
this.firstName = firstName;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
}
日志（无错误）：
2018-02-04 16:10:25.373 INFO 11892 --- [ main] c.i.server.IdeaFanServerApplication : Started IdeaFanServerApplication in 4.952 seconds (JVM running for 5.751)
2018-02-04 16:10:25.842 INFO 11892 --- [ main] o.n.o.drivers.bolt.request.BoltRequest : Request: UNWIND {rows} as row MERGE (n:`Fan`{id: row.props.id}) SET n=row.props RETURN row.nodeRef as ref, ID(n) as id, row.type as type with params {rows=[{nodeRef=-1, type=node, props={firstName=Fan, id=45a22c54-27a0-47af-bb8e-f4b9d3195d94}}]}
谁能看出问题出在哪里？
所有节点 classes 应该在同一个包中以便被扫描，尝试将所有 classes 移动到与 class Fan 相同的包中。简而言之，在这个包中：
new SessionFactory(configuration(), "com.ideafan.server.neo4j.node");
更新：在将 @Id 字段放入基本摘要 class 时，请确保根据 this discussion 用 @NodeEntity 注释基本摘要 class。