LazyInitializationException在訪問@Id時

我們在我們的wicket/spring/hibernate應用程序中發現了org.hibernate.LazyInitializationException。很少發生這種情況，也許每隔100代碼運行一次。首先，當我們訪問延遲加載的對象數據（大約每隔100次代碼運行時），我們就會得到異常。所以我們認爲如果我們手動將對象加載到內存中，通過使用其ID從數據庫中獲取它，問題就會得到解決。我們的理解是，註明javax.persistence.Id的字段應該始終在內存中。令我們驚訝的是，當訪問ID時，我們仍然會得到例外。也許一個例子更清楚..LazyInitializationException在訪問@Id時

這些都是我們的POJO的：

public abstract class SuperDimension{ @Id @GeneratedValue(generator = "Dimension_id_gen", strategy = GenerationType.TABLE) @GenericGenerator(name = "Dimension_id_gen", strategy = "uuid") protected String UUID; /*getters, setters and abstract stuff*/ } public class Dimension extends SuperDimension{ private String number; /*getters, setters and overridden methods*/ } public class DimensionHolder{ @OneToOne(fetch = FetchType.LAZY) @JoinColumn(name = "myDim") private Dimension myDim; /*getters, setters*/ }

我們有DimensionHolder的一個實例，並希望得到它的尺寸（myDims）號。起初，我們這樣做：在.getNumber

dimensionHolder.getMyDim().getNumber();

這引起了（每100次）延遲初始化異常（）。這是當我們試圖訪問數前手動加載它：

Dimension freshDimensionFromDataBase = dataBase.getDimensionFromUUID(dimensionHolder.getMyDim().getUUID); String number = freshDimensionFromDataBase.getNumber();

這還是引起了對.getUUID延遲初始化異常（）。即使myDim是代理，是否該ID仍然可用？

是否有可能是id在Dimensions超類中，而且我們使用的Dimension的當前實例是來自hibernate的代理對象？這在我們耳中聽起來很奇怪，所以也許某種靈魂可以爲我們的問題提供一些啓示。

謝謝！

編輯：這裏的堆棧跟蹤：

Root cause: org.hibernate.LazyInitializationException: could not initialize proxy - no Session Root Cause Message: LazyInitializationException: could not initialize proxy - no Session Message: WicketRuntimeException: Method onRequest of interface org.apache.wicket.behavior.IBehaviorListener targeted at eyesys.web.invoice.invoice.InvoicePage$20 {event='onclick'} on component [WebMarkupContainer [Component id = okayButton]] threw an exception at org.apache.wicket.RequestListenerInterface.internalInvoke(RequestListenerInterface.java:270) at org.apache.wicket.RequestListenerInterface.invoke(RequestListenerInterface.java:241) at org.apache.wicket.request.handler.ListenerInterfaceRequestHandler.invokeListener(ListenerInterfaceRequestHandler.java:255) at org.apache.wicket.request.handler.ListenerInterfaceRequestHandler.respond(ListenerInterfaceRequestHandler.java:234) at org.apache.wicket.request.cycle.RequestCycle$HandlerExecutor.respond(RequestCycle.java:781) at org.apache.wicket.request.RequestHandlerStack.execute(RequestHandlerStack.java:64) at org.apache.wicket.request.cycle.RequestCycle.execute(RequestCycle.java:255) at org.apache.wicket.request.cycle.RequestCycle.processRequest(RequestCycle.java:212) at org.apache.wicket.request.cycle.RequestCycle.processRequestAndDetach(RequestCycle.java:283) at org.apache.wicket.protocol.http.WicketFilter.processRequest(WicketFilter.java:185) at org.apache.wicket.protocol.http.WicketFilter.doFilter(WicketFilter.java:241) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293) at org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:879) at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:600) at org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:1703) at java.lang.Thread.run(Thread.java:662) Caused by: at sun.reflect.GeneratedMethodAccessor78.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.apache.wicket.RequestListenerInterface.internalInvoke(RequestListenerInterface.java:260) at org.apache.wicket.RequestListenerInterface.invoke(RequestListenerInterface.java:241) at org.apache.wicket.request.handler.ListenerInterfaceRequestHandler.invokeListener(ListenerInterfaceRequestHandler.java:255) at org.apache.wicket.request.handler.ListenerInterfaceRequestHandler.respond(ListenerInterfaceRequestHandler.java:234) at org.apache.wicket.request.cycle.RequestCycle$HandlerExecutor.respond(RequestCycle.java:781) at org.apache.wicket.request.RequestHandlerStack.execute(RequestHandlerStack.java:64) at org.apache.wicket.request.cycle.RequestCycle.execute(RequestCycle.java:255) at org.apache.wicket.request.cycle.RequestCycle.processRequest(RequestCycle.java:212) at org.apache.wicket.request.cycle.RequestCycle.processRequestAndDetach(RequestCycle.java:283) at org.apache.wicket.protocol.http.WicketFilter.processRequest(WicketFilter.java:185) at org.apache.wicket.protocol.http.WicketFilter.doFilter(WicketFilter.java:241) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293) at org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:879) at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:600) at org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:1703) at java.lang.Thread.run(Thread.java:662) Caused by: at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:167) at org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:215) at org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer.invoke(JavassistLazyInitializer.java:190) at eyesys.domain.Dimension3_$$_javassist_17.getUUID(Dimension3_$$_javassist_17.java) at eyesys.web.invoice.invoice.lines2.AccountingLineRow$33.validate(AccountingLineRow.java:918) at org.apache.wicket.markup.html.form.Form.validateFormValidator(Form.java:1826) at org.apache.wicket.markup.html.form.Form.validateFormValidators(Form.java:1839) at org.apache.wicket.markup.html.form.Form$17.component(Form.java:1865) at org.apache.wicket.markup.html.form.Form$17.component(Form.java:1853) at org.apache.wicket.util.visit.Visits.visitPostOrderHelper(Visits.java:273) at org.apache.wicket.util.visit.Visits.visitPostOrderHelper(Visits.java:261) at org.apache.wicket.util.visit.Visits.visitPostOrderHelper(Visits.java:261) at org.apache.wicket.util.visit.Visits.visitPostOrderHelper(Visits.java:261) at org.apache.wicket.util.visit.Visits.visitPostOrderHelper(Visits.java:261) at org.apache.wicket.util.visit.Visits.visitPostOrderHelper(Visits.java:261) at org.apache.wicket.util.visit.Visits.visitPostOrderHelper(Visits.java:261) at org.apache.wicket.util.visit.Visits.visitPostOrderHelper(Visits.java:261) at org.apache.wicket.util.visit.Visits.visitPostOrderHelper(Visits.java:261) at org.apache.wicket.util.visit.Visits.visitPostOrderHelper(Visits.java:261) at org.apache.wicket.util.visit.Visits.visitPostOrderHelper(Visits.java:261) at org.apache.wicket.util.visit.Visits.visitPostOrderHelper(Visits.java:261) at org.apache.wicket.util.visit.Visits.visitPostOrderHelper(Visits.java:261) at org.apache.wicket.util.visit.Visits.visitPostOrderHelper(Visits.java:261) at org.apache.wicket.util.visit.Visits.visitPostOrderHelper(Visits.java:261) at org.apache.wicket.util.visit.Visits.visitPostOrderHelper(Visits.java:261) at org.apache.wicket.util.visit.Visits.visitPostOrderHelper(Visits.java:261) at org.apache.wicket.util.visit.Visits.visitPostOrder(Visits.java:244) at org.apache.wicket.markup.html.form.Form.validateNestedForms(Form.java:1851) at org.apache.wicket.markup.html.form.Form.validate(Form.java:1715) at org.apache.wicket.markup.html.form.Form.process(Form.java:803) at org.apache.wicket.markup.html.form.Form.onFormSubmitted(Form.java:762) at org.apache.wicket.ajax.form.AjaxFormSubmitBehavior.onEvent(AjaxFormSubmitBehavior.java:158) at org.apache.wicket.ajax.AjaxEventBehavior.respond(AjaxEventBehavior.java:184) at org.apache.wicket.ajax.AbstractDefaultAjaxBehavior.onRequest(AbstractDefaultAjaxBehavior.java:369) at sun.reflect.GeneratedMethodAccessor78.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.apache.wicket.RequestListenerInterface.internalInvoke(RequestListenerInterface.java:260) at org.apache.wicket.RequestListenerInterface.invoke(RequestListenerInterface.java:241) at org.apache.wicket.request.handler.ListenerInterfaceRequestHandler.invokeListener(ListenerInterfaceRequestHandler.java:255) at org.apache.wicket.request.handler.ListenerInterfaceRequestHandler.respond(ListenerInterfaceRequestHandler.java:234) at org.apache.wicket.request.cycle.RequestCycle$HandlerExecutor.respond(RequestCycle.java:781) at org.apache.wicket.request.RequestHandlerStack.execute(RequestHandlerStack.java:64) at org.apache.wicket.request.cycle.RequestCycle.execute(RequestCycle.java:255) at org.apache.wicket.request.cycle.RequestCycle.processRequest(RequestCycle.java:212) at org.apache.wicket.request.cycle.RequestCycle.processRequestAndDetach(RequestCycle.java:283) at org.apache.wicket.protocol.http.WicketFilter.processRequest(WicketFilter.java:185) at org.apache.wicket.protocol.http.WicketFilter.doFilter(WicketFilter.java:241) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293) at org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:879) at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:600) at org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:1703) at java.lang.Thread.run(Thread.java:662)

AccountingLineRow = DimensionHolder。

Dimension3 =尺寸。

來源

2013-02-28 bumaklion

你可以發佈stacktrace嗎？ – ben75 2013-02-28 10:26:41

LazyInitializationException總是在首次訪問由延遲加載加載的子元素之前關閉會話時發生。您的代碼sniplet不夠長，無法查看可能發生的情況。 – Johanna 2013-02-28 10:37:31

添加了堆棧跟蹤。 – bumaklion 2013-02-28 12:57:12

AFAIK，代理被初始化，無論您調用哪種方法。而且可能有充足的理由這樣做。例如，您的getId()方法可以包含以下說明：

public void getId() { 
    LOG.debug("getId() called for entity with ID " + this.id + " and name " + name); 
    return this.id; 
}

如果代理未初始化，登錄名會是零，這是不正確的。

我讀過某處說，如果您使用屬性訪問類型而不是字段訪問類型（即，如果您的getter註釋的映射註釋比您的字段更精確），則在調用getId()時，代理未初始化。

但我只是在關閉會話之前初始化對象，而不是初始化它之後，通過發出新的sessio和新的數據庫查詢。

來源

2013-02-28 13:41:22

「如果代理未初始化，則記錄的名稱將爲空，這將是不正確的。」 - 但這是我們試圖訪問的ID，而不是名稱。從stacktrace：'eyesys.domain.Dimension3 _ $$ _ javassist_17.getUUID（Dimension3 _ $$ _ javassist_17.java）'。 – bumaklion 2013-02-28 15:44:42

LazyInitializationException在訪問@Id時

回答

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