| --- |
| layout: core-developers |
| title: Configuration Elements |
| --- |
| |
| # Configuration Elements |
| |
| A web application uses a deployment descriptor to initialize resources like servlets and taglibs. The deployment |
| descriptor is formatted as a XML document and named `web.xml`. |
| |
| Likewise, the framework uses a configuration file to initialize its own resources. These resources include: |
| - _Interceptors_ that can preprocess and postprocess a request |
| - _Action classes_ that can call business logic and data access code |
| - _Results_ that can prepare views, like JavaServer Pages and FreeMarker templates |
| |
| At runtime, there is a single configuration for an application. Prior to runtime, the configuration is defined through |
| one or more XML documents, including the default `struts.xml` document. There are several elements that can be configured, |
| including packages, namespaces, includes, actions, results, interceptors, and exceptions. |
| |
| > See [struts.xml](struts-xml) for a working example. |
| |
| ## Administrative Elements |
| |
| - [Bean Configuration](bean-configuration) |
| - [Constant Configuration](constant-configuration) |
| - [Package Configuration](package-configuration) |
| - [Namespace Configuration](namespace-configuration) |
| - [Include Configuration](include-configuration) |
| |
| ## Request Handling Elements |
| |
| - [Interceptor Configuration](include-configuration) |
| - [Action Configuration](action-configuration) |
| - [Wildcard Mappings](wildcard-mappings) |
| - [Result Configuration](result-configuration) |
| - [Unknown Handlers](unknown-handlers) |
| |
| ## Error Handling |
| |
| - [Exception Configuration](exceptio-configuration) |
