An Application Server is a server that has an ability to run web applications. That is to say applications to handle incoming web request, and generate an appropriate response. An application server has a role distinct from that of a web server. These are two essential components and both Tomcat can do.
A Tomcat Java application server can generate HTML response to a request after making a number of operations (connection to a database, an LDAP directory …). For the client (usually a web browser), there is no difference between a static web page: it still receives the HTML language ET to only understand how the response made to server-side exchange.
Requests for the client do not differ either if it wants to access a static resource or a web application, it still uses a URL in the same format (standard HTTP).
- The customer sends a request (ie calling a URL) to a resource request to the server. Example:
- http://bodhost.com/. He Does not know the answer here if will be received IS static (simple HTML page) or dynamic (generated by a web application). In our case, that this is an application meets at welcome on the server bodhost.com.
- On the server side, the web server (eg Apache) that processes incoming HTTP requests. Therefor it deals with all applications, They require a static or dynamic resource. Only one HTTP server does not know answer to requests for static resources. It Can Only return HTML pages, images, etc … existing ones.
- Thus, if the HTTP server finds that the received request is for the application server, it sends it to HTML. Both are connected by a channel named connector.
- The application server (eg Tomcat) receives the request in turn. Tomcat itself is able to execute piece of the application (the servlet ) which is for the query, based on the URL. This is done from the server side Configuration.
- Tomcat Java application server is an operation: representing a query, the other representing the response. The servlet can now work, and generate the response to the request. This May involve the consultation of data sources such as databases.
- Once the response is generated, the application server sends it back through the connector web server. And if ET recovers itself for a static resource, it simply delegates the recovery of the response to generate it properly.
- Now the simple task remains to understand HTML code by a browser as it is. And the HTTP server can return the response to the client to read it accurately.
Web server / application server
Remember the web server and application server are two separate things. These two components are needed on the actual server side, because they depend on each other. How? The application server can not handle HTTP request and the web server does not know how to run applications. These two components are essential and they should not be separated. Therefore to handle both simple HTTP requests (static resources) and web applications it needs to be operated independently. The idea is to change the connector, including one to use HTTP request instead of queries sorted from the server.
Note: Choose a hosting plan that offer dedicated resources for Tomcat such as VPS, Cloud Server Hosting, Hyper-V VPS, Dedicated Server Hosting, etc … )
