An application server and/or a Application server [] is a server in a computer network, on which special software applications are implemented.

One means thereby software applications frequent with three or multilevel architecture, how they are suggested e.g. by the J2EE or.NET Framework. A goal is named-giving it - for dreischichtige architecture, the three tasks of presentation to separate business logic and data retention. The presentation is taken over by a Client, gladly a Thin Client, for example by a Webbrowser, which represents a surface definition e.g. in HTML or Swing. But ASP, JSP/Servlets, PHP or ColdFusion are often used. The business logic becomes pretty often into business processes (session Bean with J2EE) and business objects divided (Entity Beans with J2EE) and in a programming language such as Java, VB.NET, C#, Perl, PHP realizes. For the data retention usually a relational data base becomes like e.g. PostgreSQL, MySQL, Oracle, DB2 or ms SQL server assigned.

Presentation layer

The presentation layer in a Application server scenario serves the representation of contents and the receipt of user input for the representation of contents exists different alternatives:

• HTML/XHTML, XML, XForms, SVG, SMIL and other languages created for the WWW. These contents are produced by ASPs, JSPs/Servlets, PHP programs or CGIs.
• Swing, AWT, MFC, Qt, Gtk and other Toolkits for the development of graphic user surfaces.

For data exchange between presentation layer and business logic layer there are several alternatives likewise:

• SOAP, XML-RPC
• Java RMI
• CORBA/IIOP
• DCOM
• SUN RPC (Remote Procedure Call)

Business logic layer

The business logic layer realizes the actual business model, as the business objects and business process taken part in the business model are implemented.

Because Thin Clients with Webbrowsern are particularly popular Clients for Application server, most Application server is either additions of Web servers (e.g. Perl or PHP for Apache or IIS) or contains a Web server (e.g. Tomcat in JBoss, WebSphere or WebLogic).

For data exchange between business logic layer and data retention layer data base interfaces are used such as JDBC, ODBC or perl DBI as well as alternatively the direct access to the DBMS (e.g. with PHP).

Data retention layer

Despite object-oriented programming also today a relational DBMS is still usually used, in order to realize the data retention for Application server. Frequently thereby one exists "„1: 1 "“- illustration of business object classes on tables and/or business object instances on Tabellenzeilen (data records). These illustrations Object relational Mapping one calls.

Characteristics

A Application server is characterized by the following characteristics:

Applications must be developed for a certain type by Application server (types e.g. are. J2EE, .NET, SAP). A Application server offers a run time environment for the server part to Client servers of an application (with applications of Web the Webbrowser is the Client part of application) also

• explicit characteristics:
  • Packaging of data sources (adapter standardized to data bases, Message Queueing, directory services, applications)
  • Interface to services with high order: Asynchronous communication, transaction processing, data manipulation & persistence

• implicit characteristics:
  • Scaling barness, without having to modify application
  • Monitoring, calibration, LOGGING and management functions at run-time

In the meantime the designation became generally accepted Application server for J2EE-Server (BEA Weblogic, IBM WebSphere, Oracle iAS, JBoss, SUN One) and becomes synonymous for the component of an application of Web (e.g. Webmail when Lycos, search and offering with eBay or Amazon) used, dynamically the sides produces, although many of these functions do not need the function range of a Application server (a Web server with Scripting would be sufficient).

The manufacturers accomplish a differentiation of their products over the not standardized aspects: Performance with the binding of different data sources, management functions for cluster, baking UP integration, detailing the monitoring, prioritization of applications.

See also

• Application server (list)
• Apple WebObjects
• J2EE
• JBoss Application server
• .NET
• Zope
• OpenLaszlo
• GNUstepWeb

Related links

• of http://www.theserverside.com/reviews/matrix.tss list of the Application servers with all features (English)

Articles in category "Application server"

We found here 3 articles.

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