只能解决Java中的failed to lazily initialize a collection of role问题

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net.sf.json.JSONException: org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.gwl.bos.model.Region.subareas, could not initialize proxy - no Session
    at net.sf.json.JSONObject.defaultBeanProcessing(JSONObject.java:818)
    at net.sf.json.JSONObject._fromBean(JSONObject.java:699)
    at net.sf.json.JSONObject.fromObject(JSONObject.java:172)
    at net.sf.json.AbstractJSON._processValue(AbstractJSON.java:274)
    at net.sf.json.JSONArray._processValue(JSONArray.java:2513)
    at net.sf.json.JSONArray.processValue(JSONArray.java:2538)
    at net.sf.json.JSONArray.addValue(JSONArray.java:2525)
    at net.sf.json.JSONArray._fromCollection(JSONArray.java:1056)
    at net.sf.json.JSONArray.fromObject(JSONArray.java:123)
    at com.gwl.bos.web.action.base.BaseAction.responseJson(BaseAction.java:72)
    at com.gwl.bos.web.action.RegionAction.listJson(RegionAction.java:112)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at ognl.OgnlRuntime.invokeMethod(OgnlRuntime.java:902)
    at ognl.OgnlRuntime.callAppropriateMethod(OgnlRuntime.java:1547)
    at ognl.ObjectMethodAccessor.callMethod(ObjectMethodAccessor.java:68)
    at com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor.callMethodWithDebugInfo(XWorkMethodAccessor.java:98)
    at com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor.callMethod(XWorkMethodAccessor.java:90)
    at ognl.OgnlRuntime.callMethod(OgnlRuntime.java:1623)
    at ognl.ASTMethod.getValueBody(ASTMethod.java:91)
    at ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:212)
    at ognl.SimpleNode.getValue(SimpleNode.java:258)
    at ognl.Ognl.getValue(Ognl.java:470)
    at ognl.Ognl.getValue(Ognl.java:434)
    at com.opensymphony.xwork2.ognl.OgnlUtil$3.execute(OgnlUtil.java:401)
    at com.opensymphony.xwork2.ognl.OgnlUtil.compileAndExecuteMethod(OgnlUtil.java:453)
    at com.opensymphony.xwork2.ognl.OgnlUtil.callMethod(OgnlUtil.java:399)
    at com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:438)
    at com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:293)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:254)
    at org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:250)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
    at com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:179)
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:99)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
    at com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:263)
    at org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:49)
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:99)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
    at com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.doIntercept(ConversionErrorInterceptor.java:142)
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:99)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
    at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:137)
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:99)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
    at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:137)
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:99)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
    at com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:201)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
    at org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:67)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
    at org.apache.struts2.interceptor.DateTextFieldInterceptor.intercept(DateTextFieldInterceptor.java:133)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
    at org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:89)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
    at org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:243)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
    at com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:101)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
    at com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:142)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
    at com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:160)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
    at com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:175)
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:99)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
    at org.apache.struts2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:121)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
    at org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:167)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
    at com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:203)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
    at com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:196)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
    at com.gwl.bos.web.interceptor.LoginInterceptor.doIntercept(LoginInterceptor.java:14)
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:99)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
    at org.apache.struts2.factory.StrutsActionProxy.execute(StrutsActionProxy.java:48)
    at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:574)
    at org.apache.struts2.dispatcher.ExecuteOperations.executeAction(ExecuteOperations.java:79)
    at org.apache.struts2.dispatcher.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:141)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.springframework.orm.hibernate5.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:155)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:200)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:678)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:836)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1747)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.gwl.bos.model.Region.subareas, could not initialize proxy - no Session
    at org.hibernate.collection.internal.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:602)
    at org.hibernate.collection.internal.AbstractPersistentCollection.withTemporarySessionIfNeeded(AbstractPersistentCollection.java:217)
    at org.hibernate.collection.internal.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:581)
    at org.hibernate.collection.internal.AbstractPersistentCollection.read(AbstractPersistentCollection.java:148)
    at org.hibernate.collection.internal.PersistentSet.hashCode(PersistentSet.java:458)
    at java.base/java.util.HashMap.hash(HashMap.java:339)
    at java.base/java.util.HashMap.put(HashMap.java:607)
    at java.base/java.util.HashSet.add(HashSet.java:220)
    at net.sf.json.AbstractJSON.addInstance(AbstractJSON.java:63)
    at net.sf.json.JSONArray._fromCollection(JSONArray.java:1035)
    at net.sf.json.JSONArray.fromObject(JSONArray.java:123)
    at net.sf.json.AbstractJSON._processValue(AbstractJSON.java:240)
    at net.sf.json.JSONObject._processValue(JSONObject.java:2655)
    at net.sf.json.JSONObject.processValue(JSONObject.java:2721)
    at net.sf.json.JSONObject.setInternal(JSONObject.java:2736)
    at net.sf.json.JSONObject.setValue(JSONObject.java:1424)
    at net.sf.json.JSONObject.defaultBeanProcessing(JSONObject.java:765)
    ... 106 more

 解决方法：<many-to-one> & <set> 中设置 lazy="false" （默认选项是 lazy = "proxy" ）

        <!-- 一对多的关系映射 -->
        <set name="subareas" lazy="false">
            <key column="region_id"></key>
            <one-to-many class="com.gwl.bos.model.Subarea"></one-to-many>
        </set>

        <!-- 多对一的映射 -->
        <many-to-one name="region" lazy="false" class="com.gwl.bos.model.Region" column="region_id"></many-to-one>

到此，关于“只能解决Java中的failed to lazily initialize a collection of role问题”的学习就结束了，希望能够解决大家的疑惑。理论与实践的搭配能更好的帮助大家学习，快去试试吧！若想继续学习更多相关知识，请继续关注亿速云网站，小编会继续努力为大家带来更多实用的文章！