HTTP状态500怎么解决，初学者，求大神，下面是代码

l_shua 2014-01-31 10:52:51

报错提示：
type Exception report

message

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

exception

javax.servlet.ServletException: Wrapper cannot find servlet class com.tsinghua.hello or a class it depends on
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:856)
org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:744)
org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80)
org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
java.lang.Thread.run(Unknown Source)
root cause

java.lang.ClassNotFoundException: com.tsinghua.hello
org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1332)
org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1181)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:856)
org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:744)
org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80)
org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
java.lang.Thread.run(Unknown Source)
note The full stack trace of the root cause is available in the Apache Tomcat/5.5.9 logs.
代码：

package com.tsinghua;
import javax.servlet.*;
import java.io.*;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import java.io.IOException;
public class hello{
/**
* Method init
*
*
* @param parm1
*
@throws ServletException
*
*/
public void init(ServletConfig parm1) throws ServletException {
// TODO: Add your code here
System.out.println("init it");
}

/**
* Method getServletConfig
*
*
* @return
*
*/
public ServletConfig getServletConfig() {
// TODO: Add your code here
return null;
}

/**
* Method service
*
*
* @param parm1
* @param parm2
*
@throws ServletException
@throws IOException
*
*/
public void service(ServletRequest req, ServletResponse res) throws ServletException, IOException {
// TODO: Add your code here
System.out.println("service it");
PrintWriter pw=res.getWriter();
pw.println("helloworld");
}

/**
* Method getServletInfo
*
*
* @return
*
*/
public String getServletInfo() {
// TODO: Add your code here
return null;
}

/**
* Method destroy
*
*
*/
public void destroy() {
// TODO: Add your code here
System.out.println("destyoy it");

}

}

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