在GWT项目中用JSP替换静态主机页时出现java ClassCastException
我想为我的GWT项目使用一个JSP主机页来自动检测区域设置，如postHow to get the Current Locale in GWT using LocaleInfo中所建议的那样
<meta name="gwt:property" content="locale=<%=request.getLocale()%>">
但是，当我尝试在superdev模式下运行应用程序时，甚至在不添加此标记的情况下，我会得到500个服务器错误，堆栈跟踪如下：
java.lang.ClassCastException: org.apache.el.ExpressionFactoryImpl cannot be cast to javax.el.ExpressionFactory
at javax.el.ExpressionFactory.newInstance(ExpressionFactory.java:198)
at javax.el.ExpressionFactory.newInstance(ExpressionFactory.java:117)
at org.apache.jasper.compiler.PageInfo.<init>(PageInfo.java:79)
at org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:110)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:373)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:353)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:340)
at org.apache.jasper.JspCompilationContext.
compile(JspCompilationContext.java:646)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:357)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:686)
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:501)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:137)
at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:557)
at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:231)
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1086)
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:428)
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:193)
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1020)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:135)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:116)
at org.eclipse.jetty.server.handler.RequestLogHandler.handle(RequestLogHandler.java:68)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:116)
at org.eclipse.jetty.server.Server.handle(Server.java:370)
at org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:489)
at org.eclipse.jetty.server.AbstractHttpConnection.headerComplete(AbstractHttpConnection.java:949)
at org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.headerComplete(AbstractHttpConnection.java:1011)
at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:644)
at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:235)
at org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:82)
at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:668)
at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:52)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:608)
at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:543)
at java.lang.Thread.run(Thread.java:722)
JSP是：
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
<link type="text/css" rel="stylesheet" href="play.css">
<script type="text/javascript" src="play/play.nocache.js"></script>
<title>Insert title here</title>
</head>
<body>
</body>
</html>
我已经尝试添加javax。el api jar与我的构建路径相同，但问题仍然存在。谷歌搜索这个类的铸造例外不会带来任何相关的
# 1 楼答案
原来我的GWT项目引用的是一个java项目，它的构建路径中有Tomcat库。这显然是在gwt超级开发模式下与jetty产生冲突。当我拆除图书馆时，冲突得到了解决