使用 JSTL 会导致更改时出现 deferredExpression 错误
我最近按照这篇帖子。但现在，如果我尝试更改我的视图之一，我会收到 deferredExpression 错误。要消除该错误，我只需终止然后重新启动项目即可。
这是怎么回事？ eclipse 不能即时编译 jstl 吗？我可以更改某些内容，这样我就不必每次更改时都重新部署吗？
堆栈跟踪
java.lang.NoSuchFieldError: deferredExpression
at org.apache.taglibs.standard.tag.common.core.ForEachSupport.release(ForEachSupport.java:212)
at org.apache.jasper.runtime.TagHandlerPool.release(TagHandlerPool.java:166)
at org.apache.jsp.l.profile_jsp._jspDestroy(profile_jsp.java:114)
at org.apache.jasper.runtime.HttpJspBase.destroy(HttpJspBase.java:88)
at org.apache.jasper.servlet.JspServletWrapper.destroy(JspServletWrapper.java:428)
at org.apache.jasper.servlet.JspServletWrapper.getServlet(JspServletWrapper.java:139)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:329)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
at com.google.appengine.tools.development.PrivilegedJspServlet.access$101(PrivilegedJspServlet.java:23)
at com.google.appengine.tools.development.PrivilegedJspServlet$2.run(PrivilegedJspServlet.java:59)
at java.security.AccessController.doPrivileged(Native Method)
at com.google.appengine.tools.development.PrivilegedJspServlet.service(PrivilegedJspServlet.java:57)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
at com.google.appengine.tools.appstats.AppstatsFilter.doFilter(AppstatsFilter.java:141)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.appspot.MySite.Controller.FacebookLogin.doFilter(FacebookLogin.java:140)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.appengine.tools.development.HeaderVerificationFilter.doFilter(HeaderVerificationFilter.java:35)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:58)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:122)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.appengine.tools.development.BackendServersFilter.doFilter(BackendServersFilter.java:97)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
at com.google.apphosting.utils.jetty.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:70)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:351)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:326)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:923)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:547)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409)
at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)
I recently removed all scriptlets on my project as advised by this post. But now, if I try and make a change to one of my views, I get a deferredExpression error. To get rid of the error, I simply have to terminate, then restart the project.
What is going on here? Is eclipse not able to compile jstl on the fly? Is there something I can change so I don't have to redeploy every time I make a change?
Stack Trace
java.lang.NoSuchFieldError: deferredExpression
at org.apache.taglibs.standard.tag.common.core.ForEachSupport.release(ForEachSupport.java:212)
at org.apache.jasper.runtime.TagHandlerPool.release(TagHandlerPool.java:166)
at org.apache.jsp.l.profile_jsp._jspDestroy(profile_jsp.java:114)
at org.apache.jasper.runtime.HttpJspBase.destroy(HttpJspBase.java:88)
at org.apache.jasper.servlet.JspServletWrapper.destroy(JspServletWrapper.java:428)
at org.apache.jasper.servlet.JspServletWrapper.getServlet(JspServletWrapper.java:139)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:329)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
at com.google.appengine.tools.development.PrivilegedJspServlet.access$101(PrivilegedJspServlet.java:23)
at com.google.appengine.tools.development.PrivilegedJspServlet$2.run(PrivilegedJspServlet.java:59)
at java.security.AccessController.doPrivileged(Native Method)
at com.google.appengine.tools.development.PrivilegedJspServlet.service(PrivilegedJspServlet.java:57)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
at com.google.appengine.tools.appstats.AppstatsFilter.doFilter(AppstatsFilter.java:141)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.appspot.MySite.Controller.FacebookLogin.doFilter(FacebookLogin.java:140)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.appengine.tools.development.HeaderVerificationFilter.doFilter(HeaderVerificationFilter.java:35)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:58)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:122)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.appengine.tools.development.BackendServersFilter.doFilter(BackendServersFilter.java:97)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
at com.google.apphosting.utils.jetty.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:70)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:351)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:326)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:923)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:547)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409)
at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)
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评论（2）
您的类路径被不同的 JSTL 实现版本污染。此特定异常意味着类路径中同时存在 JSTL 1.2 的
jstl-1.2.jar文件和 JSTL 1.1 或 1.0 的standard.jar文件。该字段是在 JSTL 1.2 中引入的，并且ForEachSupport类存在于两个 JAR 文件中。显然，在某个时刻，standard.jar已被加载并使用，同时 JVM 内存中仍保留有 JSTL 1.2 API。解决方案是删除
standard.jar。 JSTL 1.2 根本不需要它。另请参阅：
更新：根据评论，您实际上还需要删除 jstl-1.2.jar，因为 Servlet 2.5 兼容版本的 GAE/Jetty 显然已经随 JSTL 1.1 一起发布 盒子。这与 JSTL 1.2 相冲突。在你的网络应用程序中。
Your classpath is polluted with different JSTL implementation versions. This particular exception means that you've both the
jstl-1.2.jarfile of JSTL 1.2 and thestandard.jarfile of JSTL 1.1 or 1.0 in the classpath. This field is introduced in JSTL 1.2 and theForEachSupportclass is present in the both JAR files. Apparently at some point the one ofstandard.jaris been loaded and used while still having the JSTL 1.2 API in JVM memory.The solution is to remove the
standard.jar. You don't need it for JSTL 1.2 at all.See also:
Update: as per the comments, you actually need to remove the
jstl-1.2.jaras well, because the Servlet 2.5 compatible version of GAE/Jetty apparently already ships with JSTL 1.1 out the box. This was conflicting with JSTL 1.2. in your webapp.您很可能有两个版本的 JSTL (javax.servlet:jstl:)。删除旧版本并确保在使用旧版本的所有地方都更新版本，这样就可以了。
You most likely have two versions of JSTL (javax.servlet:jstl:). Remove the older version and make sure you update the version everywhere you were using the older one, and you should be good.