说明：  1、在eclipse中建立一个web网站 2、在eclipse中配置tomcat9，config目录用tomcat自身的 3、编辑server.xml，发布网站 4、在eclipse中修改网站的程序，刷新网页观察
(1. Establish a web website in eclipse 2, configure tomcat9 in eclipse, config directory with Tomcat itself. 3, edit server.xml, publish web site 4, modify the website program in eclipse, refresh web page observation.)