Question

java.lang.NoClassDefFoundError: javax/el/ELResolver

HTTP Status 500 - java.lang.NoClassDefFoundError: javax/el/ELResolver
type Exception report
message java.lang.NoClassDefFoundError: javax/el/ELResolver
description The server encountered an internal error that prevented it from fulfilling this request.
exception javax.servlet.ServletException: java.lang.NoClassDefFoundError: javax/el/ELResolver
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:268)
javax.servlet.http.HttpServlet.service(HttpServlet.java:723)
root cause java.lang.NoClassDefFoundError: javax/el/ELResolver
java.lang.ClassLoader.defineClass1(Native Method)
java.lang.ClassLoader.defineClassCond(ClassLoader.java:631)

Answer 1

少了EL表达式包，到apache-tomcat/lib目录下，拷贝el-api.jar到项目中就行了

Answer 2

原因可能有二，若你曾用过连接池，则可能是web-tomcat/conf下的server.xml文件有问题。若仍不行，则很有可能是web.xml文件中出现错误配置。最好将原来添加的配置都注释掉，再运行下试试，若可以。则说明就是web.xml中配置错误啦！