初学者关于servlet 500的错误，求大神解答

[呵呵哒_007]

type Exception report

message Error instantiating servlet class com.qiangge.servelet.HelloWorldServlet

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

exception

javax.servlet.ServletException: Error instantiating servlet class com.qiangge.servelet.HelloWorldServlet
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:503)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:526)
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1078)
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:655)
org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:222)
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1566)
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1523)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
java.lang.Thread.run(Thread.java:745)
root cause

java.lang.ClassNotFoundException:xxx.HelloWorldServlet
org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1324)
org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1177)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:503)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:526)
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1078)
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:655)
org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:222)
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1566)
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1523)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
java.lang.Thread.run(Thread.java:745)
note The full stack trace of the root cause is available in the Apache Tomcat/8.0.9 logs.

[蝶恋花雨]

java不会，应该是哪里没配置好，检查下面的方法 1：servlet-api.jar已经复制到jdk里的ext目录 中 Java\jdk1.6.0_32\jre\lib\ext\servlet-api.jar 2：类名前有public并继承HttpServlet 3：已经用package定义包了,class文件在web-inf/classes/包中的目录中 4：环境变量 classpath里加上了Java\jdk1.6.0_32\jre\lib\ext\servlet-api.jar java_home:Java\jdk1.6.0_32\jre\

[街头小贩]

com.qiangge.servelet.HelloWorldServlet web.xml中配置与类路径一致吗？是不是少打了什么