没辙了。在建了个web工程就加了javax.servlet.jsp.jar这个包，按照自定义标签步骤都做好，在tomcat5.5下跑了起来，没问题，问题是换到tomcat6.0.33的版本居然报错了。死活查不了是什么原因。错误如下。
2011-12-13 10:16:31 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet jsp threw exception
org.apache.jasper.JasperException: Unable to compile class for JSP:
An error occurred at line: 31 in the generated java file
The method getJspApplicationContext(ServletContext) is undefined for the type JspFactory
Stacktrace:
at org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.java:92)
at org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:330)
at org.apache.jasper.compiler.JDTCompiler.generateClass(JDTCompiler.java:439)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:356)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:334)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:321)
at org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:592)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:328)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
at org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:877)
at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:594)
at org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:1675)
at java.lang.Thread.run(Thread.java:662)
本来是在struts2的环境下想加入自己的自定义标签，无奈报错，后来才有这后面的工程。
测试不同版本的tomcat居然还会不一样，晕死了。（5.5下成功，6.0报错），例子最简单的，想测通就ok，好继续后面的事。当然网上查了很多例子了，调通，很多说是包的问题，就是查不出了。第一次提问不太会什么规矩，还望多包涵
