Class FrameworkServlet

All Implemented Interfaces:
Servlet, ServletConfig, Serializable, Aware, ApplicationContextAware, EnvironmentAware, EnvironmentCapable
Direct Known Subclasses:

public abstract class FrameworkServlet extends HttpServletBean implements ApplicationContextAware
Base servlet for Spring's web framework. Provides integration with a Spring application context, in a JavaBean-based overall solution.

This class offers the following functionality:

  • Manages a WebApplicationContext instance per servlet. The servlet's configuration is determined by beans in the servlet's namespace.
  • Publishes events on request processing, whether or not a request is successfully handled.

Subclasses must implement doService(jakarta.servlet.http.HttpServletRequest, jakarta.servlet.http.HttpServletResponse) to handle requests. Because this extends HttpServletBean rather than HttpServlet directly, bean properties are automatically mapped onto it. Subclasses can override initFrameworkServlet() for custom initialization.

Detects a "contextClass" parameter at the servlet init-param level, falling back to the default context class, XmlWebApplicationContext, if not found. Note that, with the default FrameworkServlet, a custom context class needs to implement the ConfigurableWebApplicationContext SPI.

Accepts an optional "contextInitializerClasses" servlet init-param that specifies one or more ApplicationContextInitializer classes. The managed web application context will be delegated to these initializers, allowing for additional programmatic configuration, e.g. adding property sources or activating profiles against the context's environment. See also ContextLoader which supports a "contextInitializerClasses" context-param with identical semantics for the "root" web application context.

Passes a "contextConfigLocation" servlet init-param to the context instance, parsing it into potentially multiple file paths which can be separated by any number of commas and spaces, like "test-servlet.xml, myServlet.xml". If not explicitly specified, the context implementation is supposed to build a default location from the namespace of the servlet.

Note: In case of multiple config locations, later bean definitions will override ones defined in earlier loaded files, at least when using Spring's default ApplicationContext implementation. This can be leveraged to deliberately override certain bean definitions via an extra XML file.

The default namespace is "'servlet-name'-servlet", e.g. "test-servlet" for a servlet-name "test" (leading to a "/WEB-INF/test-servlet.xml" default location with XmlWebApplicationContext). The namespace can also be set explicitly via the "namespace" servlet init-param.

As of Spring 3.1, FrameworkServlet may now be injected with a web application context, rather than creating its own internally. This is useful in Servlet 3.0+ environments, which support programmatic registration of servlet instances. See FrameworkServlet(WebApplicationContext) Javadoc for details.

Rod Johnson, Juergen Hoeller, Sam Brannen, Chris Beams, Rossen Stoyanchev, Phillip Webb
See Also: