Question

当我有实体有以下 -

@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "question", nullable = false, referencedColumnName="id")

我得到以下错误。然而，在仅将@ManyToOne关联作为EAGER后，错误消失，将双向@OneToMany保留为LAZY。

如何使用Spring DATA REST与LAZY @ManyToOne一起使用

java.lang.IllegalArgumentException: Id must be assignable to Serializable! Object of class [null] must be an instance of interface java.io.Serializable
at org.springframework.util.Assert.isInstanceOf(Assert.java:339)
at org.springframework.data.rest.webmvc.support.RepositoryEntityLinks.linkToSingleResource(RepositoryEntityLinks.java:160)
at org.springframework.data.rest.webmvc.PersistentEntityResourceAssembler.getSelfLinkFor(PersistentEntityResourceAssembler.java:203)
at org.springframework.data.rest.webmvc.PersistentEntityResourceAssembler.wrap(PersistentEntityResourceAssembler.java:107)
at org.springframework.data.rest.webmvc.PersistentEntityResourceAssembler.toResource(PersistentEntityResourceAssembler.java:84)
at org.springframework.data.rest.webmvc.RepositoryPropertyReferenceController$1.apply(RepositoryPropertyReferenceController.java:141)
at org.springframework.data.rest.webmvc.RepositoryPropertyReferenceController$1.apply(RepositoryPropertyReferenceController.java:110)
at org.springframework.data.rest.webmvc.RepositoryPropertyReferenceController.doWithReferencedProperty(RepositoryPropertyReferenceController.java:464)
at org.springframework.data.rest.webmvc.RepositoryPropertyReferenceController.followPropertyReference(RepositoryPropertyReferenceController.java:148)
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.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:215)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:132)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:749)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:689)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:83)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:938)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:870)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:961)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:852)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:687)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:837)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:769)
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:585)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:577)
at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:223)
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1125)
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:515)
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:185)
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1059)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:215)
at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:110)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:97)
at org.eclipse.jetty.server.Server.handle(Server.java:497)
at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:311)
at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:248)
at org.eclipse.jetty.io.AbstractConnection$2.run(AbstractConnection.java:540)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:610)
at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:539)
at java.lang.Thread.run(Thread.java:745)

网址错误：/ api / users / 2 / question

{
  "cause" : null,
  "message" : "Id must be assignable to Serializable! Object of class [null] must be an instance of interface java.io.Serializable"
}

Answer 1

现在似乎在1.8 M1版本中解决了问题。如JIRA中所述，

“请务必添加将Jackson Hibernate 4模块添加到类路径中让杰克逊适当地代理代理。“

Answer 2

Fetch注释中的

@ManyToOne是可选的，为什么要关心这一点。 @ManyToOne注释定义了与具有多对一多重性的另一个实体类的单值关联。请尝试以下方案。

@ManyToOne
@JoinColumn(name="childTable_id", nullable = false, referencedColumnName="id")

如果你想使用延迟初始化工作，请试试这个，

@ManyToOne(fetch=FetchType.Lazy)
@JoinColumn(name="childTable_id", nullable = false, referencedColumnName="id")

ID必须可分配给Serializable with LAZY @ManyToOne

2 个答案: