1
我有以下类，它是较大的域结构的一部分。换句话说，Squad不是文档的基础：在集合上引用具有@DBRef注释的文档
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;
}
}
如何Player长相并不具有相关性的问题。
我使用Spring Data MongoDB版本1.10.1，这允许我使用@DBRef引用Player S作为单独的文件。
存储和阅读我正在扩展的文档MongoRepository。
我没有问题存储文档，但是当从数据库中读取它们时，Spring Data会尝试使用List构造函数创建Squad。
我尝试保持我的域名清洁，并且由于一个小队应该包含独特的球员，Set使得感觉。此外，我想避免使用构造函数混淆我的类（例如默认构造函数），只是为了使这个工作。作为一个方面说明，我试图让我的域名不可变。
如何让Spring Data MongoDB知道如何在从数据库读取数据库时将一组实例化为一组Player？或者这只是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作为参数可以工作，但正如我所说我想避免这种情况。我也尝试使用一个私人的构造函数在Collection，但然后Spring数据期望没有参数构造函数（我猜是因为两个构造函数在哪里找到）。
也许并不相关，但这是堆栈跟踪我得到：
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]
什么我的测试控制器返回：
{
"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 [[email protected], my.package.per[email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]]",
"path": "/club"
}
基于字段和基于setter的注入都可以正常工作，并使用spring的收集转换器转换为'Set'。这不会帮助您处理不可变的部分。看起来像创建bean的相关代码（基于构造函数的注入）是批量获取DBRef到List中，然后传递它以创建Bean，并在过程中丢失目标类型'Set'。如果你喜欢，你可以在这里创建一个jira。 https://jira.spring.io/secure/Dashboard.jspa –
Veeram
我可能是错的，但您可能需要它作为List，因为Spring Mongo DB实现可能需要索引和排序。如果你真的想要一个Set，你唯一的选择可能是保持它作为一个内部的实现细节，并转换到其他地方的一个集合。 – Snickers3192
@Veeram您的评论有资格作为答案。您是否深入了解源代码并发现它总是使用列表来实例化对象？一个私有默认构造函数和一个私有setter（接受'Collection'）是否可以解决这个问题？ Spring会使用私有构造函数和私有setter来实例化对象吗？ –
Magnilex