初学者：请帮忙看看问题出现在哪里，，关于tomcat+jsp的。
HTTP   Status   500   -  

--------------------------------------------

type   Exception   report

message  

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

exception  

org.apache.jasper.JasperException
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:372)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)


root   cause  

java.lang.NullPointerException
org.apache.jsp.login_jsp._jspService(login_jsp.java:72)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:94)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:324)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)


note   The   full   stack   trace   of   the   root   cause   is   available   in   the   Apache   Tomcat/5.0.28   logs.



------解决方案--------------------
最基本的错误，你照着你所做的例子再重新做一下试试看
------解决方案--------------------
jsp页面错误
------解决方案--------------------
看看你页面配置有没有问题，连接正不正常，这个不算大问题
------解决方案--------------------
到%tomcat%\work\Catalina\localhost\目录下面找到你的那个工程。
然后打开login_jsp.java文件。看看72行是什么，你的错误就在那里！
------解决方案--------------------
java.lang.NullPointerException
login_jsp的72行代码出现空指针异常.
我的异常网推荐解决方案：The server encountered an internal error () that prevented it from fulfilling this request.,http://www.aiyiweb.com/java-web/317.html