500 Servlet Exception

freemarker.core.InvalidReferenceException: Expression s.expect is undefined
on line 7, column 11 in news/prize/open/ssc.ftl.
	at freemarker.core.TemplateObject.assertNonNull(TemplateObject.java:124)
	at freemarker.core.Expression.getStringValue(Expression.java:118)
	at freemarker.core.Expression.getStringValue(Expression.java:93)
	at freemarker.core.DollarVariable.accept(DollarVariable.java:76)
	at freemarker.core.Environment.visit(Environment.java:209)
	at freemarker.core.MixedContent.accept(MixedContent.java:92)
	at freemarker.core.Environment.visit(Environment.java:209)
	at freemarker.core.IteratorBlock$Context.runLoop(IteratorBlock.java:179)
	at freemarker.core.Environment.visit(Environment.java:416)
	at freemarker.core.IteratorBlock.accept(IteratorBlock.java:102)
	at freemarker.core.Environment.visit(Environment.java:209)
	at freemarker.core.MixedContent.accept(MixedContent.java:92)
	at freemarker.core.Environment.visit(Environment.java:209)
	at freemarker.core.Environment.visit(Environment.java:394)
	at freemarker.core.BodyInstruction.accept(BodyInstruction.java:93)
	at freemarker.core.Environment.visit(Environment.java:209)
	at freemarker.core.MixedContent.accept(MixedContent.java:92)
	at freemarker.core.Environment.visit(Environment.java:209)
	at freemarker.core.Environment.visit(Environment.java:298)
	at freemarker.core.CompressedBlock.accept(CompressedBlock.java:73)
	at freemarker.core.Environment.visit(Environment.java:209)
	at freemarker.core.MixedContent.accept(MixedContent.java:92)
	at freemarker.core.Environment.visit(Environment.java:209)
	at freemarker.core.EscapeBlock.accept(EscapeBlock.java:84)
	at freemarker.core.Environment.visit(Environment.java:209)
	at freemarker.core.Macro$Context.runMacro(Macro.java:168)
	at freemarker.core.Environment.visit(Environment.java:602)
	at freemarker.core.UnifiedCall.accept(UnifiedCall.java:106)
	at freemarker.core.Environment.visit(Environment.java:209)
	at freemarker.core.MixedContent.accept(MixedContent.java:92)
	at freemarker.core.Environment.visit(Environment.java:209)
	at freemarker.core.Environment.process(Environment.java:189)
	at freemarker.template.Template.process(Template.java:237)
	at yixun.wap.freemarker.FreemarkerDo.doMark(FreemarkerDo.java:47)
	at _jsp._page._news._prize._open._ssc__jsp._jspService(page/news/prize/open/ssc.jsp:41)
	at com.caucho.jsp.JavaPage.service(JavaPage.java:61)
	at com.caucho.jsp.Page.pageservice(Page.java:586)
	at com.caucho.server.dispatch.PageFilterChain.doFilter(PageFilterChain.java:190)
	at yixun.wap.filter.ReplaceTextFilter.doFilter(ReplaceTextFilter.java:77)
	at com.caucho.server.dispatch.FilterFilterChain.doFilter(FilterFilterChain.java:73)
	at com.caucho.server.webapp.WebAppFilterChain.doFilter(WebAppFilterChain.java:167)
	at com.caucho.server.dispatch.ServletInvocation.service(ServletInvocation.java:226)
	at com.caucho.server.http.HttpRequest.handleRequest(HttpRequest.java:263)
	at com.caucho.server.port.TcpConnection.run(TcpConnection.java:477)
	at com.caucho.util.ThreadPool$Item.runTasks(ThreadPool.java:591)
	at com.caucho.util.ThreadPool$Item.run(ThreadPool.java:513)
	at java.lang.Thread.run(Thread.java:619)


注：
由于freemarker強(qiáng)烈不支持null，所以這個(gè)問題呢，多半就是JSP（或拋數(shù)據(jù)源的地方）數(shù)據(jù)沒有正確的傳過來。究其原因，不在ftl模板。
MyEclipse控制臺(tái)輸出：一看知道哪個(gè)頁面，哪行錯(cuò)了，so easy……  O(∩_∩)O~
[09:44:50.546] Compiling _jsp/_page/_news/_prize/_open/_ssc__jsp.java
[ERROR] 
Expression s.expect is undefined on line 7, column 11 in news/prize/open/ssc.ftl.
The problematic instruction:
----------
==> ${s.expect} [on line 7, column 9 in news/prize/open/ssc.ftl]
?in user-directive f.page [on line 3, column 1 in news/prize/open/ssc.ftl]
----------

Java backtrace for programmers:
----------
freemarker.core.InvalidReferenceException: Expression s.expect is undefined on line 7, column 11 in news/prize/open/ssc.ftl.
?at freemarker.core.TemplateObject.assertNonNull(TemplateObject.java:124)
?at freemarker.core.Expression.getStringValue(Expression.java:118)
……
……