现状:
把filter\SetCharacterEncodingFilter.class放在web-inf\classes目录
在web.xml中添加
    <welcome-file-list>
        <welcome-file>index.html</welcome-file>
        <welcome-file>index.htm</welcome-file>
        <welcome-file>index.jsp</welcome-file>
    </welcome-file-list>
 
  <filter>
   <filter-name>Set Character Encoding</filter-name>
   <filter-class>filters.SetCharacterEncodingFilter</filter-class>
   <init-param>
    <param-name>encoding</param-name>
    <param-value>GBK</param-value>
   </init-param>
  </filter>
  <filter-mapping>
   <filter-name>Set Character Encoding</filter-name>
   <url-pattern>/*</url-pattern>
  </filter-mapping>
后,启动tomcat5.0.28,出现
2007-3-13 17:43:46 org.apache.catalina.core.StandardContext start
严重: Error filterStart
2007-3-13 17:43:46 org.apache.catalina.core.StandardContext start
严重: Context startup failed due to previous errors
解决办法:
c:\> cd 主页目录\web-inf\classes
c:\> jar cvf   filters.jar   filters
形成filters.jar文件,把它放在 tomcat\common\lib下,重新启动tomcat,问题解决!