Thanks! Now,I am clear about it. If I want to use "http://huaiyin.cf" instead of "http://huaiyin.cf/huaiyin", what should I do? Do I need to name it "ROOT.war"?
I have put "huaiyin.war" in "/home/huaiyin/". Then,I login "http://johnny.heliohost.org:2082/frontend/x3/java/index.live.php".It is redirected "http://johnny.heliohost.org:2082/cpsess7417316650/frontend/paper_lantern/java/index.live.php?login=1&post_login=17546368057709". HTTP error 404 The requested page was not found. Possible reasons why you are seeing this page: A bookmarked URL may have changed since you last visited. The URL was entered incorrectly. The URL was entered with inaccurate capitalization (URLs are case sensitive). Please re-check the URL you are trying to reach. (Go Back) Why?
http://huaiyin.heliohost.org/jsptest.jsp HTTP Status 404 - /jsptest.jsp But,The PHP files can be accessed. http://huaiyin.heliohost.org/filebox.php And now, I changed the domain to "huaiyin.cf".