Struts2 严重: Exception starting filter struts2

In this directory you find two jar files: xercesImpl.jar and xml-apis.jar needed by tomcat and that must be loaded before all xmsl stuff present in the jdk (1.4 naming problem). And in the file xml-apis.jar the TransformerFactoryImpl is set to "org.apache.xalan.processor.TransformerFactoryImpl". 

解决办法： 
1. 将xml-apis.jar移出endorsed文件夹。 
2. 用xalan系列jar包替换原来的xercesImpl.jar和xml-apis.jar。 
xalan系列jar包：serializer.jar、xalan.jar、xercesImpl.jar和xml-apis.jar。 
3. For other application, just check this file or dom3-xml-apis.jar in your class path.