我按照书上面得HelloWorld的配置和做法，完全一样可是我的就是不出现HelloWorld这个页面，总是出现
HTTP Status 404 -
--------------------------------------------------------------------------------
type Status report
message
description The requested resource () is not available.
--------------------------------------------------------------------------------
Apache Tomcat/6.0.20
HTTP Status 404 -
--------------------------------------------------------------------------------
type Status report
message
description The requested resource () is not available.
--------------------------------------------------------------------------------
Apache Tomcat/6.0.20
