Servlet Web.xml配置问题！请高手指教！
------------------------------错误信息----------------------------------
type Exception report

message

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

exception

javax.servlet.ServletException: Error allocating a servlet instance
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:151)
org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:870)
org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:685)
java.lang.Thread.run(Unknown Source)


root cause

java.lang.NoClassDefFoundError: IllegalName: ok/Login
java.lang.ClassLoader.preDefineClass(Unknown Source)
java.lang.ClassLoader.defineClass(Unknown Source)
java.security.SecureClassLoader.defineClass(Unknown Source)
org.apache.catalina.loader.WebappClassLoader.findClassInternal(WebappClassLoader.java:1847)
org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:873)
org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1326)
org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1205)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:151)
org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:870)
org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:685)
java.lang.Thread.run(Unknown Source)


note The full stack trace of the root cause is available in the Apache Tomcat/5.5.23 logs.

项目结构：xxx/index.jsp,
xxx/web-inf/xml
xxx/web-inf/classes/ok/Login.class
------------------------------web.xml----------------------------------
<?xml version= "1.0 " encoding= "ISO-8859-1 "?>
<web-app xmlns= "http://java.sun.com/xml/ns/j2ee "
xmlns:xsi= "http://www.w3.org/2001/XMLSchema-instance "
xsi:schemaLocation= "http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd "
version= "2.4 ">

<display-name> Welcome to Tomcat </display-name>
<description>
ServLet Web.xml Test
</description>

<!-- JSPC servlet mappings start -->

<servlet>
<servlet-name> login </servlet-name>
<servlet-class> ok/Login </servlet-class>
</servlet>

<servlet-mapping>
<servlet-name> login </servlet-name>
<url-pattern> /login.do </url-pattern>
</servlet-mapping>

<!-- JSPC servlet mappings end -->

</web-app>
还请高手帮忙指点！多谢！多谢！

[解决办法]
和配置无关，你的jsp或者class有问题
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.myexception.cn/java-web/317.html