我正在使用Stripes，Spring，JPA和＆amp ;; Hibernate amd有一个带有多对一子集合的对象。我已将加载设置为Lazy 例如。
@OneToMany(cascade = CascadeType.MERGE, mappedBy = "paperOffering", fetch = FetchType.LAZY)
private List<PaperOfferingAssessment> paperOfferingAssessments;
现在，当我从数据库中获取这些对象的集合时，我得到了LazyInitializationException，即使我没有直接访问子集合。
我认为延迟加载意味着它只会在引用时实例化子对象集合？ 我已经尝试过查看类似的问题，但无法弄清楚这一切，所以不胜感激任何澄清。
有趣的是，我总是设置了这种关系，但实际上只是在我将数据库更改为与子表具有正确的外键关系时才注意到异常。
编辑：堆栈跟踪：
堆栈追踪：
17:39:17] ERROR org.hibernate.LazyInitializationException - failed to lazily initialize a collection of role: eis.model.PaperOffering.paperOfferingAssessments, no session or session was closed
org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: eis.model.PaperOffering.paperOfferingAssessments, no session or session was closed
at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:380)
at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationExceptionIfNotConnected(AbstractPersistentCollection.java:372)
at org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:365)
at org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:108)
at org.hibernate.collection.PersistentSet.toArray(PersistentSet.java:194)
at net.sourceforge.stripes.ajax.JavaScriptBuilder.buildCollectionNode(JavaScriptBuilder.java:524)
at net.sourceforge.stripes.ajax.JavaScriptBuilder.buildNode(JavaScriptBuilder.java:365)
at net.sourceforge.stripes.ajax.JavaScriptBuilder.buildObjectNode(JavaScriptBuilder.java:420)
at net.sourceforge.stripes.ajax.JavaScriptBuilder.buildNode(JavaScriptBuilder.java:374)
at net.sourceforge.stripes.ajax.JavaScriptBuilder.buildArrayNode(JavaScriptBuilder.java:507)
at net.sourceforge.stripes.ajax.JavaScriptBuilder.buildCollectionNode(JavaScriptBuilder.java:524)
at net.sourceforge.stripes.ajax.JavaScriptBuilder.buildNode(JavaScriptBuilder.java:365)
at net.sourceforge.stripes.ajax.JavaScriptBuilder.build(JavaScriptBuilder.java:191)
at net.sourceforge.stripes.ajax.JavaScriptResolution.execute(JavaScriptResolution.java:75)
at net.sourceforge.stripes.controller.DispatcherHelper$7.intercept(DispatcherHelper.java:508)
at net.sourceforge.stripes.controller.ExecutionContext.proceed(ExecutionContext.java:158)
at net.sourceforge.stripes.controller.HttpCacheInterceptor.intercept(HttpCacheInterceptor.java:99)
at net.sourceforge.stripes.controller.ExecutionContext.proceed(ExecutionContext.java:155)
at net.sourceforge.stripes.controller.BeforeAfterMethodInterceptor.intercept(BeforeAfterMethodInterceptor.java:113)
at net.sourceforge.stripes.controller.ExecutionContext.proceed(ExecutionContext.java:155)
at net.sourceforge.stripes.controller.ExecutionContext.wrap(ExecutionContext.java:74)
at net.sourceforge.stripes.controller.DispatcherHelper.executeResolution(DispatcherHelper.java:502)
at net.sourceforge.stripes.controller.DispatcherServlet.executeResolution(DispatcherServlet.java:286)
at net.sourceforge.stripes.controller.DispatcherServlet.service(DispatcherServlet.java:170)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:527)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1216)
at net.sourceforge.stripes.controller.StripesFilter.doFilter(StripesFilter.java:247)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1187)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:343)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:109)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:83)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:97)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:100)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:78)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:54)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:35)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:188)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:105)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:79)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.session.ConcurrentSessionFilter.doFilter(ConcurrentSessionFilter.java:109)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:149)
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:237)
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:167)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1187)
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:421)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:119)
at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:493)
at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:225)
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:930)
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:358)
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:183)
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:866)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:117)
at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:245)
at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:126)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:113)
at org.eclipse.jetty.server.Server.handle(Server.java:351)
at org.eclipse.jetty.server.HttpConnection.handleRequest(HttpConnection.java:594)
at org.eclipse.jetty.server.HttpConnection$RequestHandler.content(HttpConnection.java:1059)
at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:764)
at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:217)
at org.eclipse.jetty.server.HttpConnection.handle(HttpConnection.java:424)
at org.eclipse.jetty.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:506)
at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:436)
at java.lang.Thread.run(Thread.java:619)
[17:39:17] WARN net.sourceforge.stripes.ajax.JavaScriptBuilder - Could not translate property [paperOfferingAssessments] of type [java.util.Set] due to an exception.
org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: eis.model.PaperOffering.paperOfferingAssessments, no session or session was closed
at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:380)
at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationExceptionIfNotConnected(AbstractPersistentCollection.java:372)
at org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:365)
at org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:108)
at org.hibernate.collection.PersistentSet.toArray(PersistentSet.java:194)
at net.sourceforge.stripes.ajax.JavaScriptBuilder.buildCollectionNode(JavaScriptBuilder.java:524)
at net.sourceforge.stripes.ajax.JavaScriptBuilder.buildNode(JavaScriptBuilder.java:365)
at net.sourceforge.stripes.ajax.JavaScriptBuilder.buildObjectNode(JavaScriptBuilder.java:420)
at net.sourceforge.stripes.ajax.JavaScriptBuilder.buildNode(JavaScriptBuilder.java:374)
at net.sourceforge.stripes.ajax.JavaScriptBuilder.buildArrayNode(JavaScriptBuilder.java:507)
at net.sourceforge.stripes.ajax.JavaScriptBuilder.buildCollectionNode(JavaScriptBuilder.java:524)
at net.sourceforge.stripes.ajax.JavaScriptBuilder.buildNode(JavaScriptBuilder.java:365)
at net.sourceforge.stripes.ajax.JavaScriptBuilder.build(JavaScriptBuilder.java:191)
at net.sourceforge.stripes.ajax.JavaScriptResolution.execute(JavaScriptResolution.java:75)
at net.sourceforge.stripes.controller.DispatcherHelper$7.intercept(DispatcherHelper.java:508)
at net.sourceforge.stripes.controller.ExecutionContext.proceed(ExecutionContext.java:158)
at net.sourceforge.stripes.controller.HttpCacheInterceptor.intercept(HttpCacheInterceptor.java:99)
at net.sourceforge.stripes.controller.ExecutionContext.proceed(ExecutionContext.java:155)
at net.sourceforge.stripes.controller.BeforeAfterMethodInterceptor.intercept(BeforeAfterMethodInterceptor.java:113)
at net.sourceforge.stripes.controller.ExecutionContext.proceed(ExecutionContext.java:155)
at net.sourceforge.stripes.controller.ExecutionContext.wrap(ExecutionContext.java:74)
at net.sourceforge.stripes.controller.DispatcherHelper.executeResolution(DispatcherHelper.java:502)
at net.sourceforge.stripes.controller.DispatcherServlet.executeResolution(DispatcherServlet.java:286)
at net.sourceforge.stripes.controller.DispatcherServlet.service(DispatcherServlet.java:170)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:527)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1216)
at net.sourceforge.stripes.controller.StripesFilter.doFilter(StripesFilter.java:247)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1187)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:343)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:109)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:83)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:97)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:100)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:78)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:54)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:35)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:188)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:105)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:79)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.session.ConcurrentSessionFilter.doFilter(ConcurrentSessionFilter.java:109)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:149)
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:237)
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:167)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1187)
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:421)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:119)
at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:493)
at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:225)
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:930)
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:358)
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:183)
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:866)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:117)
at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:245)
at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:126)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:113)
at org.eclipse.jetty.server.Server.handle(Server.java:351)
at org.eclipse.jetty.server.HttpConnection.handleRequest(HttpConnection.java:594)
at org.eclipse.jetty.server.HttpConnection$RequestHandler.content(HttpConnection.java:1059)
at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:764)
at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:217)
at org.eclipse.jetty.server.HttpConnection.handle(HttpConnection.java:424)
at org.eclipse.jetty.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:506)
at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:436)
at java.lang.Thread.run(Thread.java:619)
答案 0 :(得分：1)
Lazy意味着当有人调用get(index)或其他需要使用完全初始化集合操作的方法时，将加载集合项。 size()未初始化集合。
你的错误意味着，你的代码试图从集合中获取元素，在Hibernate会话之外工作。会话在一段时间之前关闭，所以你得到了懒惰的独立收藏。
请检查您在交易中执行与收集一起操作的代码。也许，yoiu需要使用@Transactional注释标记您的方法（如果您使用声明性描述）或将代码放在
TransactionManager tm = //get TransactionManager
try {
tm.begin();
//your code
tm.commit();
} catch (Exception e) {
tm.rollback();
}
答案 1 :(得分：0)
你确定你没有访问toString，hashCode或equals-methods中的集合吗？ hibernate可以使用后面的2将结果添加到其缓存中。