到底什么是Web Server什么是HTTP server?什么是application server?

Web server is the container which deploy and run web application, so that all the users can get access to some content through Web browser.
选用web服务器 我们要选和JSP/servlet兼容的服务器。

Web server(就是HTTP服务器): only support http protocol, html, url. the main function of it is to deliver page so that web browser can parse and render. in short, it used to handle http requests. [Apache, nginx, Tomcat(轻量级应用服务器)]
application server: used for providing function for client to use. so any server which have the application to explain and execute server-side code.（JBoss, WebLogic）

总结：
web serverhttp serverhandle http request
application server is bigger, used to explain and execute server-side code (business logic)