java.lang.LinkageError: loader constraint violation: when resolving interface method "javax.servlet.jsp.JspApplicationContext.getExpressionFactory()Ljavax/el/ExpressionFactory;" the class loader (instance of org/apache/jasper/servlet/JasperLoader) of the current class, org/apache/jsp/_1_jsp, and the class loader (instance of org/codehaus/plexus/classworlds/realm/ClassRealm) for the method's defining class, javax/servlet/jsp/JspApplicationContext, have different Class objects for the type javax/el/ExpressionFactory used in the signature
可能是由于容器提供的包和web应用引入的包冲突引起的，排除重复包。
That will happen when you include server-specific libraries of a different server make/version in the /WEB-INF/lib of your web application, such as jsp-api.jar, el-api.jar, servlet-api.jar, etc. You need to remove them all. The /WEB-INF/lib should not contain any server-specific libraries. They belongs in the specific server itself (Tomcat has them in its /lib folder already).
This is by the way a pretty common beginner's mistake whenever they encounter compilation errors on the JSP/Servlet API in their IDE project. This should have been solved differently, namely by integrating the server in the IDE and adding the server as "Target runtime" to the project.
Tomcat内置的jsp jar包和你导入的jsp jar包版本不一致，删掉一个
就是jar文件冲突了
最好使用maven来管理项目
http://blog.csdn.net/je_ge/article/details/53725357
尝试删掉同名低版本jar包