From Wikipedia, the free encyclopedia
An application server is a software
framework dedicated to the efficient execution of procedures
(scripts, routines, programs, ...) for supporting the construction
of applications. The term was created in the context of web
applications. In these, the application server acts as a set of
components accessible to the software developer through an API defined by the
platform itself. These components are usually performed in the same
machine where the web server is running, and their main job is to
support the construction of dynamic pages. [1]
Other uses of the term can refer to:123456
- the services that a server
makes available
- the computer hardware on which the services
run
Java
application servers
Following the success of the Java platform, the
term application server sometimes refers to a J2EE or Java EE
5 application server. Some of the better-known Java Enterprise
Edition application servers include:
The web modules include servlets and JavaServer Pages. Business logic
resides in Enterprise JavaBeans (EJB-3 and
later). The Hibernate project offers an EJB-3 container implementation for
the JBoss
application server. Tomcat from Apache and JOnAS from
ObjectWeb exemplify typical containers which can store these
modules.
A Java Server Page (JSP) (a servlet from Java) executes in a web container — the
Java equivalent of CGI scripts. JSPs provide a way to create
HTML pages by embedding references
to the server logic within the page. HTML coders and Java
programmers can work side by side by referencing each other's code
from within their own. JavaBeans are the independent class
components of the Java architecture from Sun
Microsystems.
The application servers mentioned above mainly serve web
applications. Some application servers target networks other
than web-based ones: Session Initiation Protocol
servers, for instance, target telephony networks.
Microsoft
platform
Microsoft has
contributed the .NET Framework to the world of
application servers. .NET technology includes the Windows Communication
Foundation, .NET
Remoting, ADO.NET, and
ASP.NET among several other
components. It works with (or depends upon) other Microsoft
products, such as Microsoft Message Queuing and
Internet Information
Services.
TrustLeap has released the G-WAN application server in July
2009. TrustLeap G-WAN, which runs in user-mode, offers 'edit &
play' scripted ANSI C servlets
that match Microsoft's IIS 7.0 static pages performances (which run
in kernel-mode). In November 2009, TrustLeap released a Linux port of G-WAN which is much
faster than the Windows version.
Microsoft definitely
lacks a sharp focus on the "application server" term. What .NET framework offers is really too much of
a low level plumbing that one can certainly utilize to build an
application server purposed for specific case i.e.: serving
business applications. For example, ITAdapter Corp. is working on a .NET-powered
technology called NFX.Backend which will deliver all
similar-to-Java services out-of-the-box.
Zend
platform
Zend
offers an application server called Zend Server — used for running and managing
PHP applications.
Other
platforms
Open-source application servers also come from other vendors.
Examples include:
Non-Java offerings have no formal interoperability
specifications on a par with the Java Specification Request. As a
result, interoperability between non-Java products is poor compared
to that of Java EE based products. To address these shortcomings,
specifications for enterprise application
integration and service-oriented
architecture were designed to connect the many different
products. These specifications include Business
Application Programming Interface, Web Services
Interoperability, and Java EE Connector
Architecture.
Advantages of application
servers
- Data and
code integrity
- By centralizing business logic on an individual server or on a
small number of server machines, updates and upgrades to the
application for all users can be guaranteed. There is no risk of
old versions of the application accessing or manipulating data in
an older, incompatible manner.
- Centralized configuration
- Changes to the application configuration, such as a move of
database server, or system settings, can take place centrally.
- Security
- A central point through which service-providers can manage
access to data and portions of the application itself counts as a
security benefit, devolving responsibility for authentication away
from the potentially insecure client layer without exposing the
database layer.
- Performance
- By limiting the network traffic to performance-tier traffic the
client-server model improves the performance of large applications
in heavy usage environments.
- Total Cost of
Ownership (TCO)
- In combination, the benefits above may result in cost savings
to an organization developing enterprise
applications. In practice, however, the technical challenges of
writing software that conforms to that paradigm, combined with the
need for software distribution to
distribute client code, somewhat negate these benefits.
- Transaction Support
- A transaction represents a unit of
activity in which many updates to resources (on the same or
distributed data sources) can be made atomic (as an indivisible
unit of work). End-users can benefit from a system-wide standard
behaviour, from reduced time to develop, and from reduced costs. As
the server does a lot of the tedious code-generation, developers
can focus on business logic.
See also
External
links
- ^
Template:Title=Designing Data Intensive Web Applications, 2Q03
Wikis
Quiz
Map
Search
