NOT_FOUND_ERR: An attempt is made to reference a node in a context where it does not exist

错误：“NOT_FOUND_ERR: An attempt is made to reference a node in a context where it does not exist.”
org.xhtmlrenderer.util.XRRuntimeException: Can't load the XML resource (using TRaX transformer). org.w3c.dom.DOMException: NOT_FOUND_ERR: An attempt is made to reference a node in a context where it does not exist.
at org.xhtmlrenderer.resource.XMLResource$XMLResourceBuilder.createXMLResource(XMLResource.java:191)
at org.xhtmlrenderer.resource.XMLResource.load(XMLResource.java:75)
at org.xhtmlrenderer.pdf.ITextRenderer.setDocumentFromString(ITextRenderer.java:158)
at org.xhtmlrenderer.pdf.ITextRenderer.setDocumentFromString(ITextRenderer.java:153)
at com.iris.egrant.utils.pdf.PDFUtil.exportPdfFile(PDFUtil.java:932)
at com.iris.egrant.utils.pdf.PDFUtil.remoteExportPdfFile(PDFUtil.java:824)
at com.iris.egrant.service.pdf.PdfServiceImpl.genPdf(PdfServiceImpl.java:627)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:317)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
at com.sun.proxy.$Proxy86.genPdf(Unknown Source)
at com.iris.egrant.webapp.struts2.pdf.PdfAction.genPdf(PdfAction.java:84)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at ognl.OgnlRuntime.invokeMethod(OgnlRuntime.java:894)
at ognl.OgnlRuntime.callAppropriateMethod(OgnlRuntime.java:1539)
at ognl.ObjectMethodAccessor.callMethod(ObjectMethodAccessor.java:68)
at com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor.callMethodWithDebugInfo(XWorkMethodAccessor.java:117)
at com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor.callMethod(XWorkMethodAccessor.java:108)
at ognl.OgnlRuntime.callMethod(OgnlRuntime.java:1615)
at ognl.ASTMethod.getValueBody(ASTMethod.java:91)
at ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:212)
at ognl.SimpleNode.getValue(SimpleNode.java:258)

解决办法：
Looks like you have issue with wrong version of xerces. Search PATH_TO_TOMCAT/webapps/YOUR_APP/WEB-INF/lib for xml-apis, xerces, xercesImpl and xmlParserAPIs. If you have 2 of them - exclude one in build.gradle.
effectively a new xercesImpl jar was the cause of the problem.
实际处理办法：mv xercesImpl-2.8.1.jar xercesImpl-2.8.1.jar_bak 将lib中的xercesImpl-2.8.1.jar删除即可