Spring Data Cassandra LocalDateTime转换

Question

我正在处理一个项目，其中我们要持久化一个有类型为LocalDateTime的字段的实体。我们知道cassandra不支持此类型转换，因此我们使用Spring的转换器支持创建了自定义转换器。然而，似乎Spring-Data-Cassandra无法识别它们或理解该字段应该映射到一个列。这是我们如何在Spring的转换服务中注册我们的转换器。

<bean id="conversionService" class="org.springframework.context.support.ConversionServiceFactoryBean">
        <property name="converters">
            <set>
                <!-- list of converters-->
                <bean class="com.klappo.userservice.api.persistence.converters.DateToLocalDateTimeConverter" />
                <bean class="com.klappo.userservice.api.persistence.converters.LocalDateTimeToDateConverter" />
                <bean class="com.klappo.userservice.api.persistence.converters.DateToLocalDateConverter" />
                <bean class="com.klappo.userservice.api.persistence.converters.LocalDateToDateConverter" />
            </set>
        </property>
    </bean>

我们的应用程序启动时会抛出以下异常：

    Caused by: 
org.springframework.data.cassandra.mapping.VerifierMappingExceptions: java.time.LocalDate:|Cassandra entities must have the @Table, @Persistent or @PrimaryKeyClass Annotation|
    at org.springframework.data.cassandra.mapping.BasicCassandraPersistentEntityMetadataVerifier.verify(BasicCassandraPersistentEntityMetadataVerifier.java:45)
    at org.springframework.data.cassandra.mapping.BasicCassandraPersistentEntity.verify(BasicCassandraPersistentEntity.java:198)
    at org.springframework.data.mapping.context.AbstractMappingContext.addPersistentEntity(AbstractMappingContext.java:297)
    at org.springframework.data.mapping.context.AbstractMappingContext$PersistentPropertyCreator.createAndRegisterProperty(AbstractMappingContext.java:469)
    at org.springframework.data.mapping.context.AbstractMappingContext$PersistentPropertyCreator.doWith(AbstractMappingContext.java:426)
    at org.springframework.util.ReflectionUtils.doWithFields(ReflectionUtils.java:607)
    at org.springframework.data.mapping.context.AbstractMappingContext.addPersistentEntity(AbstractMappingContext.java:294)
    at org.springframework.data.mapping.context.AbstractMappingContext$PersistentPropertyCreator.createAndRegisterProperty(AbstractMappingContext.java:469)
    at org.springframework.data.mapping.context.AbstractMappingContext$PersistentPropertyCreator.doWith(AbstractMappingContext.java:426)
    at org.springframework.util.ReflectionUtils.doWithFields(ReflectionUtils.java:607)
    at org.springframework.data.mapping.context.AbstractMappingContext.addPersistentEntity(AbstractMappingContext.java:294)
    at org.springframework.data.mapping.context.AbstractMappingContext.addPersistentEntity(AbstractMappingContext.java:256)
    at org.springframework.data.mapping.context.AbstractMappingContext.initialize(AbstractMappingContext.java:372)
    at org.springframework.data.cassandra.mapping.BasicCassandraMappingContext.initialize(BasicCassandraMappingContext.java:79)
    at org.springframework.data.mapping.context.AbstractMappingContext.afterPropertiesSet(AbstractMappingContext.java:362)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1612)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1549)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:539)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:302)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:298)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:328)
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:108)
    at org.springframework.beans.factory.support.ConstructorResolver.resolveConstructorArguments(ConstructorResolver.java:632)
    at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:140)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1114)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1017)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:504)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:302)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:298)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:328)
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:108)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1456)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1197)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:302)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:298)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:328)
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:108)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1456)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1197)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:302)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:298)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:328)
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:108)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1456)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1197)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:302)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:298)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:1017)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:960)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:858)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:480)
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:289)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1185)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:302)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:298)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:703)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:760)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:482)
    at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:403)
    at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:306)
    at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:106)
    at org.eclipse.jetty.server.handler.ContextHandler.callContextInitialized(ContextHandler.java:800)
    at org.eclipse.jetty.servlet.ServletContextHandler.callContextInitialized(ServletContextHandler.java:444)
    at org.eclipse.jetty.server.handler.ContextHandler.startContext(ContextHandler.java:791)
    at org.eclipse.jetty.servlet.ServletContextHandler.startContext(ServletContextHandler.java:294)
    at org.eclipse.jetty.webapp.WebAppContext.startWebapp(WebAppContext.java:1349)
    at org.eclipse.jetty.maven.plugin.JettyWebAppContext.startWebapp(JettyWebAppContext.java:296)
    at org.eclipse.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1342)
    at org.eclipse.jetty.server.handler.ContextHandler.doStart(ContextHandler.java:741)
    at org.eclipse.jetty.webapp.WebAppContext.doStart(WebAppContext.java:505)
    at org.eclipse.jetty.maven.plugin.JettyWebAppContext.doStart(JettyWebAppContext.java:365)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
    at org.eclipse.jetty.util.component.ContainerLifeCycle.start(ContainerLifeCycle.java:132)
    at org.eclipse.jetty.util.component.ContainerLifeCycle.doStart(ContainerLifeCycle.java:114)
    at org.eclipse.jetty.server.handler.AbstractHandler.doStart(AbstractHandler.java:61)
    at org.eclipse.jetty.server.handler.ContextHandlerCollection.doStart(ContextHandlerCollection.java:163)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
    at org.eclipse.jetty.util.component.ContainerLifeCycle.start(ContainerLifeCycle.java:132)
    at org.eclipse.jetty.util.component.ContainerLifeCycle.doStart(ContainerLifeCycle.java:114)
    at org.eclipse.jetty.server.handler.AbstractHandler.doStart(AbstractHandler.java:61)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
    at org.eclipse.jetty.util.component.ContainerLifeCycle.start(ContainerLifeCycle.java:132)
    at org.eclipse.jetty.server.Server.start(Server.java:387)
    at org.eclipse.jetty.util.component.ContainerLifeCycle.doStart(ContainerLifeCycle.java:114)
    at org.eclipse.jetty.server.handler.AbstractHandler.doStart(AbstractHandler.java:61)
    at org.eclipse.jetty.server.Server.doStart(Server.java:354)
    at org.eclipse.jetty.maven.plugin.JettyServer.doStart(JettyServer.java:73)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
    at org.eclipse.jetty.maven.plugin.AbstractJettyMojo.startJetty(AbstractJettyMojo.java:534)
    at org.eclipse.jetty.maven.plugin.AbstractJettyMojo.execute(AbstractJettyMojo.java:357)
    at org.eclipse.jetty.maven.plugin.JettyRunMojo.execute(JettyRunMojo.java:167)
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:132)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:208)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:116)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:80)
    at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:51)
    at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:120)
    at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:347)
    at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:154)
    at org.apache.maven.cli.MavenCli.execute(MavenCli.java:582)
    at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:214)
    at org.apache.maven.cli.MavenCli.main(MavenCli.java:158)
    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.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:289)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356)
    at org.codehaus.classworlds.Launcher.main(Launcher.java:46)

Spring的数据文档在这方面缺乏很多内容，因此我们想知道是否有人尝试过在spring-data-cassandra中使用自定义类型转换器，如果有，我们想知道正确的做法。

提前致谢。

- xburgos

Answer 1

很不幸，spring-data-cassandra版本小于等于1.2.x只能与可以直接映射到此列表中的数据类型的bean一起使用： http://www.datastax.com/documentation/developer/java-driver/1.0/java-driver/reference/javaClass2Cql3Datatypes_r.html 我遇到了同样的问题，因为想将我的类映射到Cassandra中的TEXT字段，但是无法做到。经过几天的尝试，我得出结论，在Spring-Data for Cassandra中无法使用自定义类型转换器（在版本1.2.0.M1中进行了测试）。

CassandraTemplate使用MappingCassandraConverter，其中嵌入了DefaultConversionService，但是spring-data-cassandra模块中没有使用此DefaultConversionService。它仅用于与SpringData API集成。

您可以在库的代码中找到conversionService仅在以下情况下使用的信息：

BeanWrapper<S> wrapper = BeanWrapper.create(instance, conversionService);

这只是跳过了conversionService:

@Deprecated
public static <T> BeanWrapper<T> create(T bean, ConversionService conversionService) {
    return new BeanWrapper<T>(bean);
}

您可以在MappingCassandraConverter.readPropertyFromRow(...)中看到，它使用ColumnReader.get(int i)方法，该方法仅支持Cassandra的MAP、LIST、SET和基本数据类型（Text、Numbers、UUID、java.util.Date、Boolean、ByteBuffer）。

此外，BasicCassandraMappingContext.verifier (BasicCassandraPersistentEntityMetadataVerifier)会在尝试写入任何无法映射到Cassandra支持的类型或不是@Table注释的字段时抛出异常。

这就是为什么您会遇到该异常的原因。

// it was attempt to check conversion of an embedded field 'date' in LocalDateTime    
org.springframework.data.cassandra.mapping.VerifierMappingExceptions: java.time.LocalDate

因此，解决这个问题的唯一方法是在spring-data-cassandra之上使用ConversionService来满足您的需求。

转换服务部分的示例代码:

import org.springframework.data.convert.Jsr310Converters;

...    

@Bean
public ConversionService getConversionService() {
    // creates DefaultConversionService
    ConversionServiceFactoryBean bean = new ConversionServiceFactoryBean();
    bean.setConverters(new HashSet<>(getConverters()));
    bean.afterPropertiesSet();
    ConversionService service = bean.getObject();
    return service;
}

private Set<Converter<?, ?>> getConverters() {
    Set<Converter<?,?>> converters = new HashSet<Converter<?,?>>();
    converters.addAll(Jsr310Converters.getConvertersToRegister());
    converters.add(new TimeWriteConverter());
    converters.add(new TimeReadConverter());

    return converters;
}

public static class TimeWriteConverter implements Converter<LocalDateTime, Long> {
    @Override
    public Long convert(LocalDateTime source) {
        return source.atZone(ZoneId.systemDefault()).toInstant().toEpochMilli();
    }
}
public static class TimeReadConverter implements Converter<Long, LocalDateTime> {
    @Override
    public LocalDateTime convert(Long source) {
        return LocalDateTime.ofInstant(Instant.ofEpochMilli(source), ZoneId.systemDefault());
    }
}

- Dmitry Buykin

---

你找到了任何解决方法，或者在发现这个问题后你如何实现你的映射？ - Jörn Horstmann

是的，我已经添加了额外的服务层，其中使用ConversionService编程。对于我的情况来说，这很好，因为在我的项目中需要某种时间序列API（findLatest、findRange）。它看起来像http://docs.spring.io/spring/docs/current/spring-framework-reference/html/validation.html#core-convert-programmatic-usage - Dmitry Buykin

Answer 2

我可以看到我的配置有一些不同。

首先，当您可以使用标准配置容器list时，为什么要使用set呢？

其次：如果它不起作用，请尝试使用Java代码配置并查看是否有效：

@Configuration
public class ConversionConfiguration {

    @Bean
    public ConversionService getConversionService() {
        ConversionServiceFactoryBean bean = new ConversionServiceFactoryBean();
        bean.setConverters(getConverters());
        bean.afterPropertiesSet();
        ConversionService object = bean.getObject();
        return object;
    }

    private Set<Converter> getConverters() {
        Set<Converter> converters = new HashSet<Converter>();

        converters.add(new DateToLocalDateTimeConverter());
        converters.add(new LocalDateTimeToDateConverter());
        converters.add(new DateToLocalDateConverter());
        converters.add(new LocalDateToDateConverter());

        return converters;
    }
}

- user3667171

---

你能解释一下为什么在这种情况下，Java配置与XML的行为会有所不同吗？ - Jörn Horstmann

@JörnHorstmann XML 的唯一问题是你必须等到运行时才能发现 bean 中的拼写错误或其他愚蠢的错误。另一方面，使用 Spring IDE 插件（或集成的 Spring 工具套件）肯定可以帮助你处理已实现的错误，并确保配置的完整性。 - user3667171

在我看来，基于XML的配置和注解配置之间没有实际区别，因为任何现代IDE都支持检查配置（Intelij IDEA - Spring*插件，Eclipse - Spring Tool Suite插件）。例如，在Spring配置中的任何XML通常都有很好的XSD模式覆盖，因此可以在开发的早期阶段发现拼写错误。 - Dmitry Buykin

@DmitryBuykin，您深思熟虑的评论大大扩大了我无知的范围。 - user3667171

Answer 3

由于我遇到了同样的问题，我想分享一些我的调查结果:

• spring data cassandra的验证器检查实体类的有效性，但由于字段类型LocalDateTime不是有效的简单类型，因此失败了。
• 由于cassandra映射的糟糕实现，使用自己的实现来覆盖/扩展功能非常麻烦。特别是CassandraSimpleTypeHolder有一些final和static方法，直接用在其他类中。
• 我尝试提供自己的CassandraMappingContext、CassandraPersistentProperty等实现。这允许“验证”实体，但无法进行写操作。这是由于使用的datastax驱动程序不知道LocalDateTime在其内部映射TypeCode中。因此，您必须提供LocalDateTime和Date之间的映射。这通常由ConversionService完成。但是目前我找不到任何使用它的地方。

然而，另一个选择是等待官方解决方案:

• 内部使用Datastax驱动程序。当前版本3.0具有使用额外模块处理jdk8的功能: http://www.datastax.com/dev/blog/datastax-java-driver-3-0-0-released
• 但是，当前Spring Data版本不支持3.0驱动程序和JSR310的兼容性。它将成为下一个Spring Data版本的一部分: https://github.com/spring-projects/spring-data-commons/wiki/Release-Train-Ingalls

- Indivon