java - 使用命名空间评估 xpath 表达式时出现 IncompleteClassChangeError

Question

我需要修改一个具有多个命名空间的 xml 文档。我的代码在本地计算机上运行没有问题，但当我将其部署到 IBM Websphere 应用程序服务器时遇到 java.lang.IncompleteClassChangeError。

我正在使用 xercesImpl-2.8.1.jar 和 xalan-2.7.0.jar。是什么导致了这个错误以及如何解决它？或者，是否有其他方法可以通过命名空间支持来修改 xml 文档？

代码:

System.setProperty("javax.xml.parsers.DocumentBuilderFactory", "org.apache.xerces.jaxp.DocumentBuilderFactoryImpl");

DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
dbf.setNamespaceAware(true);
DocumentBuilder db = dbf.newDocumentBuilder();
org.w3c.dom.Document doc = db.parse(new java.io.FileInputStream("c:/test.xml"));

System.setProperty("javax.xml.xpath.XPathFactory", "org.apache.xpath.jaxp.XPathFactoryImpl");
XPathFactory xf = XPathFactory.newInstance();
XPath xpath = xf.newXPath();
xpath.setNamespaceContext(new MyNamespaceContext());

// get the node for editing
String xpathExpr = ...
org.w3c.dom.Node n = (org.w3c.dom.Node)xpath.compile(xpathExpr).evaluate(doc, XPathConstants.NODE); // IncompatibleClassChangeError here

异常堆栈跟踪:

java.lang.IncompatibleClassChangeError
        at org.apache.xpath.jaxp.JAXPPrefixResolver.getNamespaceForPrefix(JAXPPrefixResolver.java:45)
        at org.apache.xpath.compiler.Lexer.mapNSTokens(Lexer.java:587)
        at org.apache.xpath.compiler.Lexer.tokenize(Lexer.java:265)
        at org.apache.xpath.compiler.Lexer.tokenize(Lexer.java:96)
        at org.apache.xpath.compiler.XPathParser.initXPath(XPathParser.java:110)
        at org.apache.xpath.XPath.<init>(XPath.java:176)
        at org.apache.xpath.XPath.<init>(XPath.java:264)
        at org.apache.xpath.jaxp.XPathImpl.compile(XPathImpl.java:394)
        at com.ibm._jsp._xml._jspService(_xml.java:94)
        at com.ibm.ws.jsp.runtime.HttpJspBase.service(HttpJspBase.java:87)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
        at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1146)
        at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:592)
        at com.ibm.ws.wswebcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:525)
        at com.ibm.wsspi.webcontainer.servlet.GenericServletWrapper.handleRequest(GenericServletWrapper.java:122)
        at com.ibm.ws.jsp.webcontainerext.AbstractJSPExtensionServletWrapper.handleRequest(AbstractJSPExtensionServletWrapper.java:232)
        at com.ibm.ws.webcontainer.webapp.WebApp.handleRequest(WebApp.java:3548)
        at com.ibm.ws.webcontainer.webapp.WebGroup.handleRequest(WebGroup.java:269)
        at com.ibm.ws.webcontainer.WebContainer.handleRequest(WebContainer.java:831)
        at com.ibm.ws.wswebcontainer.WebContainer.handleRequest(WebContainer.java:1478)
        at com.ibm.ws.webcontainer.channel.WCChannelLink.ready(WCChannelLink.java:133)
        at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleDiscrimination(HttpInboundLink.java:458)
        at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleNewInformation(HttpInboundLink.java:387)
        at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.ready(HttpInboundLink.java:267)
        at com.ibm.ws.ssl.channel.impl.SSLConnectionLink.determineNextChannel(SSLConnectionLink.java:1037)
        at com.ibm.ws.ssl.channel.impl.SSLConnectionLink$MyReadCompletedCallback.complete(SSLConnectionLink.java:644)
        at com.ibm.ws.ssl.channel.impl.SSLReadServiceContext$SSLReadCompletedCallback.complete(SSLReadServiceContext.java:1818)
        at com.ibm.ws.tcp.channel.impl.AioReadCompletionListener.futureCompleted(AioReadCompletionListener.java:165)
        at com.ibm.io.async.AbstractAsyncFuture.invokeCallback(AbstractAsyncFuture.java:217)
        at com.ibm.io.async.AsyncChannelFuture.fireCompletionActions(AsyncChannelFuture.java:161)
        at com.ibm.io.async.AsyncFuture.completed(AsyncFuture.java:136)
        at com.ibm.io.async.ResultHandler.complete(ResultHandler.java:196)
        at com.ibm.io.async.ResultHandler.runEventProcessingLoop(ResultHandler.java:751)
        at com.ibm.io.async.ResultHandler$2.run(ResultHandler.java:881)
        at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java:1497)

Answer 1

我通常的经验法则是，IncompleteClassChangeError 意味着编译器在编译时看到的某个类的版本与运行时加载的同一类的版本不兼容。堆栈跟踪显示 XPath 引擎正在对您的 NamespaceResolver 进行回调，因此应该重点关注调查。