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java引用集合上带有@DBRef注释的文档

2 月，2 周 Questions & Answers

我有下面的类，它是一个更大的域结构的一部分。换句话说，Squad不是文档的基础：

public class Squad {

  @DBRef
  private final Set<Player> players;

  public Squad(Set<Player> players) {
    this.players = ImmutableSet.copyOf(Objects.requireNonNull(players));
  }

  public Set<Player> getPlayers() {
    return players;
  }

}

Player的样子与问题无关

我正在使用Spring Data MongoDB版本1.10.1，它允许我使用^{}作为单独的文档引用Player

为了存储和阅读我正在扩展的文档^{}

我在存储文档方面没有问题，但是当从数据库中读取文档时，Spring Data尝试使用List构造函数创建Squad

我努力保持我的域名干净，因为一个球队应该包含独特的球员，一个Set是有意义的。此外，我希望避免将类与构造函数（例如默认构造函数）混在一起，这样做只是为了让它工作。顺便说一句，我试图保持我的域不变

如何让Spring Data MongoDB理解如何在从数据库读取数据时用一组Player实例化Squad还是这就是MongoDB的工作方式？（我更熟悉关系数据库/JPA，其中Set可以这样使用）

我想让构造函数接受Collection作为参数是可行的，但正如我所说的，我希望避免这种情况。我还尝试使用一个私有构造函数来接受一个Collection，但是Spring数据需要一个无参数构造函数（我猜是因为找到了两个构造函数）

也许不相关，但这是我得到的stacktrace：

java.lang.IllegalArgumentException: argument type mismatch
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_121]
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_121]
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_121]
at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_121]
at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:142) ~[spring-beans-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.data.convert.ReflectionEntityInstantiator.createInstance(ReflectionEntityInstantiator.java:76) ~[spring-data-commons-1.13.1.RELEASE.jar:na]
at org.springframework.data.convert.ClassGeneratingEntityInstantiator.createInstance(ClassGeneratingEntityInstantiator.java:83) ~[spring-data-commons-1.13.1.RELEASE.jar:na]
at org.springframework.data.mongodb.core.convert.MappingMongoConverter.read(MappingMongoConverter.java:257) ~[spring-data-mongodb-1.10.1.RELEASE.jar:na]
at org.springframework.data.mongodb.core.convert.MappingMongoConverter.read(MappingMongoConverter.java:237) ~[spring-data-mongodb-1.10.1.RELEASE.jar:na]
at org.springframework.data.mongodb.core.convert.MappingMongoConverter.readValue(MappingMongoConverter.java:1214) ~[spring-data-mongodb-1.10.1.RELEASE.jar:na]
at org.springframework.data.mongodb.core.convert.MappingMongoConverter.access$200(MappingMongoConverter.java:84) ~[spring-data-mongodb-1.10.1.RELEASE.jar:na]
at org.springframework.data.mongodb.core.convert.MappingMongoConverter$MongoDbPropertyValueProvider.getPropertyValue(MappingMongoConverter.java:1162) ~[spring-data-mongodb-1.10.1.RELEASE.jar:na]
at org.springframework.data.mongodb.core.convert.MappingMongoConverter$MongoDbPropertyValueProvider.getPropertyValue(MappingMongoConverter.java:1125) ~[spring-data-mongodb-1.10.1.RELEASE.jar:na]
at org.springframework.data.mapping.model.PersistentEntityParameterValueProvider.getParameterValue(PersistentEntityParameterValueProvider.java:78) ~[spring-data-commons-1.13.1.RELEASE.jar:na]
at org.springframework.data.mapping.model.SpELExpressionParameterValueProvider.getParameterValue(SpELExpressionParameterValueProvider.java:63) ~[spring-data-commons-1.13.1.RELEASE.jar:na]
at org.springframework.data.convert.ReflectionEntityInstantiator.createInstance(ReflectionEntityInstantiator.java:71) ~[spring-data-commons-1.13.1.RELEASE.jar:na]
at org.springframework.data.convert.ClassGeneratingEntityInstantiator.createInstance(ClassGeneratingEntityInstantiator.java:83) ~[spring-data-commons-1.13.1.RELEASE.jar:na]
at org.springframework.data.mongodb.core.convert.MappingMongoConverter.read(MappingMongoConverter.java:257) ~[spring-data-mongodb-1.10.1.RELEASE.jar:na]
at org.springframework.data.mongodb.core.convert.MappingMongoConverter.read(MappingMongoConverter.java:237) ~[spring-data-mongodb-1.10.1.RELEASE.jar:na]
at org.springframework.data.mongodb.core.convert.MappingMongoConverter.readValue(MappingMongoConverter.java:1214) ~[spring-data-mongodb-1.10.1.RELEASE.jar:na]
at org.springframework.data.mongodb.core.convert.MappingMongoConverter.access$200(MappingMongoConverter.java:84) ~[spring-data-mongodb-1.10.1.RELEASE.jar:na]
at org.springframework.data.mongodb.core.convert.MappingMongoConverter$MongoDbPropertyValueProvider.getPropertyValue(MappingMongoConverter.java:1162) ~[spring-data-mongodb-1.10.1.RELEASE.jar:na]
at org.springframework.data.mongodb.core.convert.MappingMongoConverter$MongoDbPropertyValueProvider.getPropertyValue(MappingMongoConverter.java:1125) ~[spring-data-mongodb-1.10.1.RELEASE.jar:na]
at org.springframework.data.mapping.model.PersistentEntityParameterValueProvider.getParameterValue(PersistentEntityParameterValueProvider.java:78) ~[spring-data-commons-1.13.1.RELEASE.jar:na]
at org.springframework.data.mapping.model.SpELExpressionParameterValueProvider.getParameterValue(SpELExpressionParameterValueProvider.java:63) ~[spring-data-commons-1.13.1.RELEASE.jar:na]
at org.springframework.data.convert.ReflectionEntityInstantiator.createInstance(ReflectionEntityInstantiator.java:71) ~[spring-data-commons-1.13.1.RELEASE.jar:na]
at org.springframework.data.convert.ClassGeneratingEntityInstantiator.createInstance(ClassGeneratingEntityInstantiator.java:83) ~[spring-data-commons-1.13.1.RELEASE.jar:na]
at org.springframework.data.mongodb.core.convert.MappingMongoConverter.read(MappingMongoConverter.java:257) ~[spring-data-mongodb-1.10.1.RELEASE.jar:na]
at org.springframework.data.mongodb.core.convert.MappingMongoConverter.read(MappingMongoConverter.java:237) ~[spring-data-mongodb-1.10.1.RELEASE.jar:na]
at org.springframework.data.mongodb.core.convert.MappingMongoConverter.read(MappingMongoConverter.java:197) ~[spring-data-mongodb-1.10.1.RELEASE.jar:na]
at org.springframework.data.mongodb.core.convert.MappingMongoConverter.read(MappingMongoConverter.java:193) ~[spring-data-mongodb-1.10.1.RELEASE.jar:na]
at org.springframework.data.mongodb.core.convert.MappingMongoConverter.read(MappingMongoConverter.java:84) ~[spring-data-mongodb-1.10.1.RELEASE.jar:na]
at org.springframework.data.mongodb.core.MongoTemplate$ReadDbObjectCallback.doWith(MongoTemplate.java:2313) ~[spring-data-mongodb-1.10.1.RELEASE.jar:na]
at org.springframework.data.mongodb.core.MongoTemplate.executeFindMultiInternal(MongoTemplate.java:1966) ~[spring-data-mongodb-1.10.1.RELEASE.jar:na]
at org.springframework.data.mongodb.core.MongoTemplate.doFind(MongoTemplate.java:1784) ~[spring-data-mongodb-1.10.1.RELEASE.jar:na]
at org.springframework.data.mongodb.core.MongoTemplate.doFind(MongoTemplate.java:1767) ~[spring-data-mongodb-1.10.1.RELEASE.jar:na]
at org.springframework.data.mongodb.core.MongoTemplate.find(MongoTemplate.java:641) ~[spring-data-mongodb-1.10.1.RELEASE.jar:na]
at org.springframework.data.mongodb.repository.support.SimpleMongoRepository.findAll(SimpleMongoRepository.java:359) ~[spring-data-mongodb-1.10.1.RELEASE.jar:na]
at org.springframework.data.mongodb.repository.support.SimpleMongoRepository.findAll(SimpleMongoRepository.java:197) ~[spring-data-mongodb-1.10.1.RELEASE.jar:na]
at org.springframework.data.mongodb.repository.support.SimpleMongoRepository.findAll(SimpleMongoRepository.java:51) ~[spring-data-mongodb-1.10.1.RELEASE.jar:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_121]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_121]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_121]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_121]
at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.executeMethodOn(RepositoryFactorySupport.java:504) ~[spring-data-commons-1.13.1.RELEASE.jar:na]
at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.doInvoke(RepositoryFactorySupport.java:489) ~[spring-data-commons-1.13.1.RELEASE.jar:na]
at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:461) ~[spring-data-commons-1.13.1.RELEASE.jar:na]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:61) ~[spring-data-commons-1.13.1.RELEASE.jar:na]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92) ~[spring-aop-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.data.repository.core.support.SurroundingTransactionDetectorMethodInterceptor.invoke(SurroundingTransactionDetectorMethodInterceptor.java:57) ~[spring-data-commons-1.13.1.RELEASE.jar:na]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:213) ~[spring-aop-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at com.sun.proxy.$Proxy67.findAll(Unknown Source) ~[na:na]
at my.package.TestController.getAllTeams(TestController.java:39) ~[classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_121]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_121]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_121]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_121]
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:116) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:622) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) ~[tomcat-embed-websocket-8.5.11.jar:8.5.11]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:105) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:474) [tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79) [tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:349) [tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:783) [tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:798) [tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1434) [tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.11.jar:8.5.11]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_121]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_121]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.11.jar:8.5.11]
at java.lang.Thread.run(Thread.java:745) [na:1.8.0_121]

以及我的测试控制器返回的内容：

{
  "timestamp": 1491657302229,
  "status": 500,
  "error": "Internal Server Error",
  "exception": "org.springframework.data.mapping.model.MappingInstantiationException",
  "message": "Failed to instantiate my.package.team.Squad using constructor public my.package.team.Squad(java.util.Set) with arguments [my.package.person.player.Player@2afde45b, my.package.person.player.Player@7f87e2e6, my.package.person.player.Player@337d278d, my.package.person.player.Player@3637e725, my.package.person.player.Player@732d0284, my.package.person.player.Player@337d5ed5, my.package.person.player.Player@69665678, my.package.person.player.Player@60e19abe, my.package.person.player.Player@7b439d04, my.package.person.player.Player@2211ef4f, my.package.person.player.Player@799fb8e3, my.package.person.player.Player@1547f904, my.package.person.player.Player@728bed15, my.package.person.player.Player@5fcd1f9c, my.package.person.player.Player@5b91ec26, my.package.person.player.Player@7134b189, my.package.person.player.Player@5cfa19ff, my.package.person.player.Player@6bfcdc03, my.package.person.player.Player@3fd8fd86, my.package.person.player.Player@6bb4ab0d]",
  "path": "/club"
}

共 (1) 个答案

  1. # 1 楼答案

    字段和属性访问器映射都可以很好地工作，并使用spring的集合转换器转换为Set<Player>

    这并不能帮助你解决不可改变的部分

    看起来与bean创建相关的代码是将DBRef批量获取到列表中，然后将其传递给bean创建，并在过程中丢失目标类型Set

    下面的jira已被记录，以涵盖允许集合类型进入构造函数创建的更改

    https://jira.spring.io/browse/DATAMONGO-1666

    现在的解决方法是将构造函数更改为接受Collection类型，就像您已经找到的那样