org.springframework.web.context
Class ContextLoaderServlet

java.lang.Object
  javax.servlet.GenericServlet
      javax.servlet.http.HttpServlet
          org.springframework.web.context.ContextLoaderServlet

All Implemented Interfaces:

Serializable, Servlet, ServletConfig

public class ContextLoaderServlet
extends HttpServlet

Bootstrap servlet to start up Spring's root WebApplicationContext. Simply delegates to ContextLoader.

This servlet should have a lower load-on-startup value in web.xml than any servlets that access the root web application context.

Note that this class has been deprecated for containers implementing Servlet API 2.4 or higher, in favor of ContextLoaderListener.
According to Servlet 2.4, listeners must be initialized before load-on-startup servlets. Many Servlet 2.3 containers already enforce this behavior. If you use such a container, this servlet can be replaced with ContextLoaderListener. Else or if working with a Servlet 2.2 container, stick with this servlet.

Servlet 2.3 containers known to work with bootstrap listeners are:

• Apache Tomcat 4.x
• Jetty 4.x
• Resin 2.1.8+
• Orion 2.0.2+
• BEA WebLogic 8.1 SP3

For working with any of them, ContextLoaderListener is recommended.

Servlet 2.3 containers known not to work with bootstrap listeners are:

• BEA WebLogic up to 8.1 SP2
• IBM WebSphere 5.x
• Oracle OC4J 9.0.3

If you happen to work with such a server, this servlet has to be used.

So unfortunately, the only context initialization option that is compatible with all Servlet 2.3 containers is this servlet.

Note that a startup failure of this servlet will not stop the rest of the web application from starting, in contrast to a listener failure. This can lead to peculiar side effects if other servlets get started that depend on initialization of the root web application context.

Author:

Juergen Hoeller, Darren Davison

See Also:

ContextLoader, ContextLoaderListener, Log4jConfigServlet, Serialized Form

Constructor Summary

ContextLoaderServlet()

Method Summary

protected ContextLoader	createContextLoader() Create the ContextLoader to use.
void	destroy() Close the root web application context.
ContextLoader	getContextLoader() Return the ContextLoader used by this servlet.
String	getServletInfo()
void	init() Initialize the root web application context.
void	service(HttpServletRequest request, HttpServletResponse response) This should never even be called since no mapping to this servlet should ever be created in web.xml.

Methods inherited from class javax.servlet.http.HttpServlet

doDelete, doGet, doHead, doOptions, doPost, doPut, doTrace, getLastModified, service

Methods inherited from class javax.servlet.GenericServlet

getInitParameter, getInitParameterNames, getServletConfig, getServletContext, getServletName, init, log, log

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ContextLoaderServlet

public ContextLoaderServlet()

Method Detail

init

public void init()
          throws ServletException

Initialize the root web application context.

Overrides:

init in class GenericServlet

Throws:

ServletException

createContextLoader

protected ContextLoader createContextLoader()

Create the ContextLoader to use. Can be overridden in subclasses.

Returns:

the new ContextLoader

getContextLoader

public ContextLoader getContextLoader()

Return the ContextLoader used by this servlet.

destroy

public void destroy()

Close the root web application context.

Specified by:

destroy in interface Servlet

Overrides:

destroy in class GenericServlet

service

public void service(HttpServletRequest request,
                    HttpServletResponse response)
             throws IOException

This should never even be called since no mapping to this servlet should ever be created in web.xml. That's why a correctly invoked Servlet 2.3 listener is much more appropriate for initialization work ;-)

Overrides:

service in class HttpServlet

Throws:

IOException

getServletInfo

public String getServletInfo()

Specified by:

getServletInfo in interface Servlet

Overrides:

getServletInfo in class GenericServlet