HTTP Status 500

运行某个jsp页面时提示

type Exception report

message javax.servlet.ServletException: java.lang.NoClassDefFoundError: org/apache/taglibs/standard/tag/common/core/ChooseTag

description The server encountered an internal error that prevented it from fulfilling this request.

exception org.apache.jasper.JasperException: javax.servlet.ServletException: java.lang.NoClassDefFoundError: org/apache/taglibs/standard/tag/common/core/ChooseTag

	org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:556)
	org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:462)
	org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:395)
	org.apache.jasper.servlet.JspServlet.service(JspServlet.java:339)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
	cn.itcast.servlet.FoodTypeServlet.goTo(FoodTypeServlet.java:186)
	cn.itcast.servlet.FoodTypeServlet.list(FoodTypeServlet.java:112)
	cn.itcast.servlet.FoodTypeServlet.doGet(FoodTypeServlet.java:51)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:624)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:731)

或者提示
The absolute uri: http://java.sun.com/jsp/jstl/core 
cannot be resolved in either web.xml or the jar files deployed with this application

直接将jstl.jar跟standard.jar包放在lib 重启服务器就行了。项目一定要重新发布 意思就是说你用了jstl标签没有导入
该包。也可以在web.xml直接引用jar的网址。配置一下就行了。重点：一定要在tomcat发布的目录-lib目录下看有没有
这两个jar.如果不出意外应该是没事了。