java web运行中报错： Exception Report Message Error instantiating servlet class

在运行java web中遇到如下报错：

HTTP Status 500 – Internal Server Error

Type Exception Report

Message Error instantiating servlet class [cn.java.servlet.LoginServlet]

Description The server encountered an unexpected condition that prevented it from fulfilling the request.

Exception

javax.servlet.ServletException: Error instantiating servlet class [cn.java.servlet.LoginServlet]
	org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:493)
	org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
	org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:650)
	org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
	org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:800)
	org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
	org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:806)
	org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1498)
	org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
	java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	java.lang.Thread.run(Thread.java:748)

 问题分析：在web.xml上，"内容"应该配置为servlet所在的包名.servlet的名称