javax.el.ELException: The identifier [static] is not a valid Java identifier

Tomcat 6下能够正常跑的程序，在Tomcat 7 下抛出以下异常信息：

May 25, 2012 11:35:43 AM org.apache.catalina.core.ApplicationDispatcher invoke
SEVERE: Servlet.service() for servlet jsp threw exception
javax.el.ELException: The identifier [static] is not a valid Java identifier as required by section 1.19 of the EL specification (Identifier ::= Java language identifier). This check can be disabled by setting the system property org.apache.el.parser.SKIP_IDENTIFIER_CHECK to true.
at org.apache.el.parser.AstIdentifier.setImage(AstIdentifier.java:132)
at org.apache.el.parser.ELParser.Identifier(ELParser.java:1215)
at org.apache.el.parser.ELParser.NonLiteral(ELParser.java:1191)
at org.apache.el.parser.ELParser.ValuePrefix(ELParser.java:1017)
at org.apache.el.parser.ELParser.Value(ELParser.java:966)
at org.apache.el.parser.ELParser.Unary(ELParser.java:948)
at org.apache.el.parser.ELParser.Multiplication(ELParser.java:712)
at org.apache.el.parser.ELParser.Math(ELParser.java:632)
at org.apache.el.parser.ELParser.Compare(ELParser.java:444)

原因是Tomcat 7 默认对标识符（identiifeers）过分讲究，吹毛求疵，所以，当访问到没有根据的标识符时就会抛出上面的异常信息。正如异常信息所描述的：是因为[static]这个标志符号引起。

我在jsp页面中搜索“static”，发现了这句：

<link rel="stylesheet" type="text/css" href="${static}/style/css/form_button_style.css">

后来发现static没有定义。

解决方案：

最直接的方法就是在启动tomcat的时候设置 SKIP_IDENTIFIER_CHECK=true 
export JAVA_OPTS="-Dorg.apache.el.parser.SKIP_IDENTIFIER_CHECK=true"

Open the file "catalina.properties" under $CATALINA_HOME/conf
Add "org.apache.el.parser.SKIP_IDENTIFIER_CHECK=true" at the end of this file
Save the file
Restart the Tomcat server
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