Struts2 jar内的checkbox.tfl内的Freemarker异常

将应用程序迁移到struts 2时，在测试页面时，在呈现页面时遇到以下异常。看起来struts 2库使用了Freemarker。你知道如何解决这个问题吗？。它显示struts 2.5.26 jar中的“template/simple/checkbox.ftl”在jar文件中有一些参数

ERROR (freemarker.runtime) Error executing FreeMarker template
FreeMarker template error:
The following has evaluated to null or missing:
==> parameters.name  [in template "template/simple/checkbox.ftl" at line 21, column 32]

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Tip: It's the step after the last dot that caused this error, not those before it.
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Tip: If the failing expression is known to legally refer to something that's sometimes null or missing, either specify a default value like myOptionalVar!myDefault, or use <#if myOptionalVar??>when-present<#else>when-missing</#if>. (These only cover the last step of the expression; to cover the whole expression, use parenthesis: (myOptionalVar.foo)!myDefault, (myOptionalVar.foo)??
----

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FTL stack trace ("~" means nesting-related):
    - Failed at: ${parameters.name?html}  [in template "template/simple/checkbox.ftl" at line 21, column 30]
----

Java stack trace (for programmers):
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freemarker.core.InvalidReferenceException: [... Exception message was already printed; see it above ...]
    at freemarker.core.InvalidReferenceException.getInstance(InvalidReferenceException.java:134)
    at freemarker.core.EvalUtil.coerceModelToTextualCommon(EvalUtil.java:481)
    at freemarker.core.EvalUtil.coerceModelToStringOrMarkup(EvalUtil.java:401)
    at freemarker.core.EvalUtil.coerceModelToStringOrMarkup(EvalUtil.java:370)
    at freemarker.core.BuiltInForLegacyEscaping._eval(BuiltInForLegacyEscaping.java:34)
    at freemarker.core.Expression.eval(Expression.java:101)
    at freemarker.core.DollarVariable.calculateInterpolatedStringOrMarkup(DollarVariable.java:100)
    at freemarker.core.DollarVariable.accept(DollarVariable.java:63)
    at freemarker.core.Environment.visit(Environment.java:347)
    at freemarker.core.Environment.visit(Environment.java:353)
    at freemarker.core.Environment.process(Environment.java:326)
    at freemarker.template.Template.process(Template.java:383)
    at org.apache.struts2.components.template.FreemarkerTemplateEngine.renderTemplate(FreemarkerTemplateEngine.java:149)
    at org.apache.struts2.components.UIBean.mergeTemplate(UIBean.java:580)
    at org.apache.struts2.components.UIBean.end(UIBean.java:536)
    at org.apache.struts2.views.jsp.ComponentTagSupport.doEndTag(ComponentTagSupport.java:39)
    at org.apache.jsp.pages.history_jsp._jspx_meth_s_005fcheckbox_005f1(history_jsp.java:2780)
    at org.apache.jsp.pages.history_jsp._jspx_meth_c_005fotherwise_005f1(history_jsp.java:2355)
    at org.apache.jsp.pages.history_jsp._jspx_meth_c_005fchoose_005f1(history_jsp.java:1328)
    at org.apache.jsp.pages.history_jsp._jspService(history_jsp.java:294)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:748)
    at org.apache.catalina.core.ApplicationDispatcher.doInclude(ApplicationDispatcher.java:604)
    at org.apache.catalina.core.ApplicationDispatcher.include(ApplicationDispatcher.java:543)
    at org.apache.jasper.runtime.JspRuntimeLibrary.include(JspRuntimeLibrary.java:954)
    at org.apache.jasper.runtime.PageContextImpl.doInclude(PageContextImpl.java:688)
    at org.apache.jasper.runtime.PageContextImpl.include(PageContextImpl.java:682)
    at org.apache.tiles.request.jsp.JspRequest.doInclude(JspRequest.java:123)
    at org.apache.tiles.request.AbstractViewRequest.dispatch(AbstractViewRequest.java:47)
    at org.apache.tiles.request.render.DispatchRenderer.render(DispatchRenderer.java:45)
    at org.apache.tiles.request.render.ChainedDelegateRenderer.render(ChainedDelegateRenderer.java:68)
    at org.apache.tiles.impl.BasicTilesContainer.render(BasicTilesContainer.java:259)
    at org.apache.tiles.TilesContainerWrapper.render(TilesContainerWrapper.java:108)
    at org.apache.tiles.template.InsertAttributeModel.renderAttribute(InsertAttributeModel.java:188)
    at org.apache.tiles.template.InsertAttributeModel.execute(InsertAttributeModel.java:132)
    at org.apache.tiles.jsp.taglib.InsertAttributeTag.doTag(InsertAttributeTag.java:300)
    at org.apache.jsp.pages.common.baseLayout_jsp._jspx_meth_tiles_005finsertAttribute_005f4(baseLayout_jsp.java:377)
    at org.apache.jsp.pages.common.baseLayout_jsp._jspService(baseLayout_jsp.java:141)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.struts2.dispatcher.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:138)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:748)
    at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:486)
    at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:411)
    at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:338)
    at org.apache.tiles.request.servlet.ServletRequest.forward(ServletRequest.java:265)
    at org.apache.tiles.request.servlet.ServletRequest.doForward(ServletRequest.java:228)
    at org.apache.tiles.request.AbstractClientRequest.dispatch(AbstractClientRequest.java:57)
    at org.apache.tiles.request.render.DispatchRenderer.render(DispatchRenderer.java:45)
    at org.apache.tiles.impl.BasicTilesContainer.render(BasicTilesContainer.java:259)
    at org.apache.tiles.impl.BasicTilesContainer.render(BasicTilesContainer.java:397)
    at org.apache.tiles.impl.BasicTilesContainer.render(BasicTilesContainer.java:238)
    at org.apache.tiles.TilesContainerWrapper.render(TilesContainerWrapper.java:103)
    at org.apache.tiles.impl.mgmt.CachingTilesContainer.render(CachingTilesContainer.java:126)
    at org.apache.struts2.views.tiles.TilesResult.doExecute(TilesResult.java:158)
    at org.apache.struts2.result.StrutsResultSupport.execute(StrutsResultSupport.java:206)
    at com.opensymphony.xwork2.DefaultActionInvocation.executeResult(DefaultActionInvocation.java:375)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:279)
    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:140)
    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:140)
    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:207)
    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 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:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:610)

执行freemarker模板时出错（freemarker.runtime） FreeMarker模板错误： 以下内容的计算结果为null或缺失： ==>parameters.name[在第21行第32列的模板“template/simple/checkbox.ftl”中] ---- 提示：导致此错误的是最后一个点之后的步骤，而不是之前的步骤。 ---- 提示：如果已知失败的表达式在法律上引用了有时为null或缺少的内容，请指定一个默认值，如myOptionalVar！myDefault，或在出现时使用缺少时使用。（这些仅包括表达式的最后一步；要覆盖整个表达式，请使用括号：（myOptionalVar.foo）！myDefault，（myOptionalVar.foo）？？ ---- ---- FTL堆栈跟踪（“~”表示嵌套相关）： -在以下位置失败：${parameters.name？html}[在模板“template/simple/checkbox.ftl”的第21行第30列] ---- Java堆栈跟踪（针对程序员）： ---- freemarker.core.InvalidReferenceException:[…已打印异常消息；请参见上文…] 位于freemarker.core.InvalidReferenceException.getInstance（InvalidReferenceException.java:134） 在freemarker.core.EvalUtil.impresseModelToTextalCommon上（EvalUtil.java:481） 位于freemarker.core.EvalUtil.impressemodeltostringormarkup（EvalUtil.java:401） 位于freemarker.core.EvalUtil.impressemodeltostringormarkup（EvalUtil.java:370） 在freemarker.core.builtinfollegacysecaving.\u eval（builtinfollegacysecaving.java:34） 位于freemarker.core.Expression.eval（Expression.java:101） 在freemarker.core.DollarVariable.calculateInterpolatedStringOrMarkup（DollarVariable.java:100）中 在freemarker.core.DollarVariable.accept（DollarVariable.java:63）中 访问（Environment.java:347） 访问（Environment.java:353） 位于freemarker.core.Environment.process（Environment.java:326） 位于freemarker.template.template.process（template.java:383） 位于org.apache.struts2.components.template.freemakerTemplateEngine.renderTemplate（freemakerTemplateEngine.java:149） 位于org.apache.struts2.components.UIBean.mergeTemplate（UIBean.java:580） 位于org.apache.struts2.components.UIBean.end（UIBean.java:536） 位于org.apache.struts2.views.jsp.ComponentTagSupport.doEndTag（ComponentTagSupport.java:39） 在org.apache.jsp.pages.history\u jsp.\u jspx\u meth\u s\u 005fcheckbox\u 005f1（history\u jsp.java:2780） 在org.apache.jsp.pages.history\u jsp.\u jspx\u meth\u c\u 005fotherwise\u 005f1（history\u jsp.java:2355） 在org.apache.jsp.pages.history\u jsp.\u jspx\u meth\u c\u 005fchoose\u 005f1（history\u jsp.java:1328） 在org.apache.jsp.pages.history\u jsp.\u jsp服务（history\u jsp.java:294）上 位于org.apache.jasper.runtime.HttpJspBase.service（HttpJspBase.java:70） 位于javax.servlet.http.HttpServlet.service（HttpServlet.java:727） 位于org.apache.jasper.servlet.JspServletWrapper.service（JspServletWrapper.java:432） 位于org.apache.jasper.servlet.JspServlet.serviceJspFile（JspServlet.java:390） 位于org.apache.jasper.servlet.JspServlet.service（JspServlet.java:334） 位于javax.servlet.http.HttpServlet.service（HttpServlet.java:727） 位于org.apache.catalina.core.ApplicationFilterChain.internalDoFilter（ApplicationFilterChain.java:303） 位于org.apache.catalina.core.ApplicationFilterChain.doFilter（ApplicationFilterChain.java:208） 位于org.apache.catalina.core.ApplicationDispatcher.invoke（ApplicationDispatcher.java:748） 位于org.apache.catalina.core.ApplicationDispatcher.doInclude（ApplicationDispatcher.java:604） 位于org.apache.catalina.core.ApplicationDispatcher.include（ApplicationDispatcher.java:543） 位于org.apache.jasper.runtime.JspRuntimeLibrary.include（JspRuntimeLibrary.java:954） 位于org.apache.jasper.runtime.PageContextImpl.doInclude（PageContextImpl.java:688） 位于org.apache.jasper.runtime.PageContextImpl.include（PageContextImpl.java:682） 位于org.apache.tiles.request.jsp.JspRequest.doInclude（JspRequest.java:123） 位于org.apache.tiles.request.AbstractViewRequest.dispatch（AbstractViewRequest.java:47） 位于org.apache.tiles.request.render.DispatchRenderer.render（DispatchRenderer.java:45） 位于org.apache.tiles.request.render.ChainedDelegateRenderer.render（ChainedDelegateRenderer.java:68） 位于org.apache.tiles.impl.BasicTilesContainer.render（BasicTilesContainer.java:259） 位于org.apache.tiles.tileContainerRapper.render（tileContainerRapper.java:108） 位于org.apache.tiles.template.InsertAttributeModel.renderAttribute（InsertAttributeModel.java:188） 位于org.apache.tiles.template.InsertAttributeModel.execute（InsertAttributeModel.java:132） 位于org.apache.tiles.jsp.taglib.InsertAttributeTag.doTag（InsertAttributeTag.java:300） 在org.apache.jsp.pages.common.baseLayout\u jsp.\u jspx\u meth\u tiles\u 005finsertatAttribute\u 005f4（baseLayout\u jsp.java:377） 在org.apache.jsp.pages.common.baseLayout_jsp._jsp服务（baseLayout_jsp.java:141）上 位于org.apache.jasper.runtime.HttpJspBase.service（HttpJspBase.java:70） 位于javax.servlet.http.HttpServlet.service（HttpServlet.java:727） 位于org.apache.jasper.servlet.JspServletWrapper.service（JspServletWrapper.java:432） 位于org.apache.jasper.servlet.JspServlet.serviceJspFile（JspServlet.java:390） 位于org.apache.jasper.servlet.JspServlet.service（JspServlet.java:334） 位于javax.servlet.http.HttpServlet.service（HttpServlet.java:727） 位于org.apache.catalina.core.ApplicationFilterChain.internalDoFilter（ApplicationFilterChain.java:303） 位于org.apache.catalina.core.ApplicationFilterChain.doFilter（ApplicationFilterChain.java:208） 位于org.apache.tomcat.websocket.server.WsFilter.doFilter（WsFilter.java:52） 位于org.apache.catalina.core.ApplicationFilterChain.int