Web server/Application Server

1. Concept

The basic function of Web server is to provide Web information browsing service. It only supports HTTP protocols, HTML document formats, and URLs. Mates with the client's Web browser. Because the Web server mainly supports the protocol is HTTP, so usually the HTTP server and the Web server is equal (there is no support other than HTTP protocol Web server, the author has not verified), said the same thing.

Application Server (Application server), let's take a look at Microsoft's definition of it: "We define the application server as the underlying system software that executes the shared business application as a server." Just as file servers provide files for many users, application servers allow multiple users to use the application at the same time (typically customer-created applications) "

2. function

In layman's words, Web server delivery (serves) pages allow the browser to browse, whereas the application server provides a method (methods) that the client application can invoke (call). To be exact, you can say that the Web server is dedicated to HTTP requests (request), but the application server is providing (serves) business logic for the application through a number of protocols.

In Java EE, for example, the Web server mainly handles static page processing and acts as a servlet container to interpret and execute servlet/jsp, while the application server runs business logic, primarily the Java EE API, such as EJB, Jndi, and JMX APIs, and includes transactional processing, Database connectivity, the application server provides more power than a Web server in an enterprise-class application.

3. General Division

With this definition, IIS, Apache, and Tomcat can all belong to the Web server, and Weblogic and WebSphere belong to the application server.

　　Apache: in a Web server, Apache is a purely Web server that is often paired with Tomcat. It has a powerful interpretation of HTML pages, but does not explain the server-side scripting code (Jsp/servlet) within the embedded page.

　　Tomcat: early Tomcat was a Jsp/servlet interpretation engine embedded in Apache Apache+tomcat equivalent to iis+asp. Later Tomcat is no longer embedded in Apache, and the Tomcat process runs independently of the Apache process. Furthermore, Tomcat is already a standalone servlet and JSP container, and the business Logic layer code and interface interaction layer code can be separated. So, someone called Tomcat a lightweight application server.

　　IIS: Microsoft's early IIS is a purely Web server. Later, it embeds an ASP engine that interprets VBScript and JScript server-side code, which can be used concurrently as an application server. Of course, it doesn't compare with the Java EE Application Server at all, but, functionally speaking, it can be called the application server in principle. To be exact, it is a Web server with a bit of application server functionality.

　　Comprehensive :

Apache is a purely Web server,

While Tomcat and IIS have the ability to interpret server-side code, they can be called a lightweight application server or a Web server with server functionality.

Weblogic, WebSphere is undoubtedly the absolute application server because it can provide the powerful Java EE function.

For Tomcat in the middle, it can be used with a pure Web server Apache, or as an application server to be deployed with the application server:

Http://jingyan.baidu.com/article/6d704a13ef0a2c28db51cade.html

Http://www.cnblogs.com/zhaoyl/archive/2012/10/10/2718575.html

Web server/Application Server