SDN4 java.lang.ClassCastException：使用AttributeConverter时无法将java.lang.Integer强制转换为java.lang.Long

Question

首先，我可能在这里做了不必要的事情，但我认为这与问题无关。 我正在尝试使用此转换器类在Neo4j中存储ZonedDateTime值：

public class ZonedDateTimeConverter implements AttributeConverter<ZonedDateTime, Long> {
    @Override
    public Long toGraphProperty(ZonedDateTime value) {
        return value != null ? value.toEpochSecond() : null;
    }

    @Override
    public ZonedDateTime toEntityAttribute(Long value) {
        if (value == null) return null;
        Instant i = Instant.ofEpochSecond(value);
        ZoneId zoneId = ZoneId.systemDefault();
        return ZonedDateTime.ofInstant(i, zoneId);
    }
}

保存值似乎可以正常工作，但是在检索时（例如，使用findOne），我得到以下信息：

org.neo4j.ogm.metadata.MappingException: Error mapping GraphModel to instance of co.sens.data.models.Transaction
    at org.neo4j.ogm.mapper.GraphEntityMapper.mapEntities(GraphEntityMapper.java:97)
    at org.neo4j.ogm.mapper.GraphEntityMapper.map(GraphEntityMapper.java:69)
    at org.neo4j.ogm.session.response.SessionResponseHandler.loadById(SessionResponseHandler.java:149)
    at org.neo4j.ogm.session.delegates.LoadOneDelegate.load(LoadOneDelegate.java:45)
    at org.neo4j.ogm.session.delegates.LoadOneDelegate.load(LoadOneDelegate.java:36)
    at org.neo4j.ogm.session.Neo4jSession.load(Neo4jSession.java:99)
    at org.springframework.data.neo4j.repository.GraphRepositoryImpl.findOne(GraphRepositoryImpl.java:60)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.executeMethodOn(RepositoryFactorySupport.java:475)
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.doInvoke(RepositoryFactorySupport.java:460)
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:432)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:61)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:281)
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:136)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:207)
    at com.sun.proxy.$Proxy112.findOne(Unknown Source)
    at co.sens.data.AccountRepositoryTest.testTransactionsForAccount(AccountRepositoryTest.java:76)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:73)
    at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:82)
    at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:73)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:224)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:83)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:68)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:163)
    at org.junit.runners.Suite.runChild(Suite.java:128)
    at org.junit.runners.Suite.runChild(Suite.java:27)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
    at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:68)
Caused by: java.lang.ClassCastException: java.lang.Integer cannot be cast to java.lang.Long
    at co.sens.data.ZonedDateTimeConverter.toEntityAttribute(ZonedDateTimeConverter.java:13)
    at org.neo4j.ogm.entityaccess.FieldWriter.write(FieldWriter.java:64)
    at org.neo4j.ogm.mapper.GraphEntityMapper.writeProperty(GraphEntityMapper.java:164)
    at org.neo4j.ogm.mapper.GraphEntityMapper.setProperties(GraphEntityMapper.java:129)
    at org.neo4j.ogm.mapper.GraphEntityMapper.mapNodes(GraphEntityMapper.java:110)
    at org.neo4j.ogm.mapper.GraphEntityMapper.mapEntities(GraphEntityMapper.java:94)
    ... 62 more

这是一个错误还是我在应该如何工作上犯了一个错误？

Answer 1

问题在于，当通过网络返回查询结果时，JSON会丢失类型信息； 在这种情况下，数值将解释为整数。

更改转换器以处理Number应该注意这一点。 这是一个例子： https : //github.com/neo4j/neo4j-ogm/blob/master/src/main/java/org/neo4j/ogm/typeconversion/DateLongConverter.java