我使用的是tomcat5.0+j2sdk1.4.2,环境变量设置是: .;%JAVA_HOME%\lib\tools.jar;%JAVA_HOME%\lib\dt.jar;D:\MYJAVA;%CATALINA_HOME%\common\lib\servlet-api.jar;
并且  JAVA_HOME:        C:\j2sdk1.4.2
      CATALINA_HOME:    D:\tomcat
      CATALINA_BASE     D:\tomcat    (我的 tomcat 安装在了D盘根目录下)
启动tomcat后,我编写的.jsp文件可以运行,servlet程序(即Test.java)可以编译成.class文件(在别人机子上可以运行),但是不能在我电脑浏览器中运行(http://localhost:8080/servlet/Test),且错误提示如下:
HTTP Status 500 -

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:118)
    org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160)
    org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:799)
    org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:705)
    org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:577)
    org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
    java.lang.Thread.run(Thread.java:534)


root cause 

java.lang.UnsupportedClassVersionError: Test (Unsupported major.minor version 49.0)
    java.lang.ClassLoader.defineClass0(Native Method)
    java.lang.ClassLoader.defineClass(ClassLoader.java:537)
我的web.xml代码如下:

<?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>
     Welcome to Tomcat
  </description>

    <servlet>
        <servlet-name>org.apache.jsp.index_jsp</servlet-name>
        <servlet-class>org.apache.jsp.index_jsp</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>org.apache.jsp.index_jsp</servlet-name>
        <url-pattern>/index.jsp</url-pattern>
    </servlet-mapping>

<servlet>
<servlet-name>Test</servlet-name>
<servlet-class>Test</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>Test</servlet-name>
<url-pattern>/servlet/Test</url-pattern>
</servlet-mapping>

</web-app>
请大家帮帮忙,我实在是不知道哪里错了,先谢谢大家了!!!