javax.faces.webapp

Class FacesServlet

java.lang.Object

javax.faces.webapp.FacesServlet

All Implemented Interfaces:

Servlet

public final class FacesServlet
extends Object
implements Servlet

FacesServlet is a servlet that manages the request processing lifecycle for web applications that are utilizing JavaServer Faces to construct the user interface.

If the application is running in a Servlet 3.0 (and beyond) container, the runtime must provide an implementation of the ServletContainerInitializer interface that declares the following classes in its HandlesTypes annotation.

• ResourceDependencies
• ResourceDependency
• javax.faces.bean.ManagedBean
• FacesComponent
• UIComponent
• Converter
• FacesConverter
• ListenerFor
• ListenersFor
• FacesBehaviorRenderer
• Renderer
• FacesValidator
• Validator

This servlet must automatically be mapped if it is not explicitly mapped in web.xml or web-fragment.xml and one or more of the following conditions are true.

• A faces-config.xml file is found in WEB-INF

• A faces-config.xml file is found in the META-INF directory of a jar in the application's classpath.

• A filename ending in .faces-config.xml is found in the META-INF directory of a jar in the application's classpath.

• The javax.faces.CONFIG_FILES context param is declared in web.xml or web-fragment.xml.

• The Set of classes passed to the onStartup() method of the ServletContainerInitializer implementation is not empty.

If the runtime determines that the servlet must be automatically mapped, it must be mapped to the following <url-pattern> entries.

• /faces
• *.jsf
• *.faces

This class must be annotated with javax.servlet.annotation.MultipartConfig. This causes the Servlet container in which the JSF implementation is running to correctly handle multipart form data.

Some security considerations relating to this class

The topic of web application security is a cross-cutting concern and every aspect of the specification address it. However, as with any framework, the application developer needs to pay careful attention to security. Please consider these topics among the rest of the security concerns for the application. This is by no means a complete list of security concerns, and is no substitute for a thorough application level security review.

Prefix mappings and the FacesServlet

If the FacesServlet is mapped using a prefix <url-pattern>, such as <url-pattern>/faces/*</url-pattern>, something must be done to prevent access to the view source without its first being processed by the FacesServlet. One common approach is to apply a <security-constraint> to all facelet files and flow definition files. Please see the Deployment Descriptor chapter of the Java Servlet Specification for more information the use of <security-constraint>.

Allowable HTTP Methods

The JSF specification only requires the use of the GET and POST http methods. If your web application does not require any other http methods, such as PUT and DELETE, please consider restricting the allowable http methods using the <http-method> and <http-method-omission> elements. Please see the Security of the Java Servlet Specification for more information the use of these elements.

Field Summary

Fields

Modifier and Type	Field and Description
static String	CONFIG_FILES_ATTR Context initialization parameter name for a comma delimited list of context-relative resource paths (in addition to /WEB-INF/faces-config.xml which is loaded automatically if it exists) containing JavaServer Faces configuration information.
static String	LIFECYCLE_ID_ATTR Context initialization parameter name for the lifecycle identifier of the Lifecycle instance to be utilized.

Constructor Summary

Constructors

Constructor and Description
FacesServlet()

Method Summary

Modifier and Type	Method and Description
void	destroy() Release all resources acquired at startup time.
ServletConfig	getServletConfig() Return the ServletConfig instance for this servlet.
String	getServletInfo() Return information about this Servlet.
void	init(ServletConfig servletConfig) Acquire the factory instances we will require.
void	service(ServletRequest req, ServletResponse resp) Process an incoming request, and create the corresponding response according to the following specification.

Methods inherited from class java.lang.Object

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

Field Detail

CONFIG_FILES_ATTR

public static final String CONFIG_FILES_ATTR

Context initialization parameter name for a comma delimited list of context-relative resource paths (in addition to /WEB-INF/faces-config.xml which is loaded automatically if it exists) containing JavaServer Faces configuration information.

See Also:

Constant Field Values

LIFECYCLE_ID_ATTR

public static final String LIFECYCLE_ID_ATTR

Context initialization parameter name for the lifecycle identifier of the Lifecycle instance to be utilized.

See Also:

Constant Field Values

Constructor Detail

FacesServlet

public FacesServlet()

Method Detail

destroy

public void destroy()

Release all resources acquired at startup time.

Specified by:

destroy in interface Servlet

getServletConfig

public ServletConfig getServletConfig()

Return the ServletConfig instance for this servlet.

Specified by:

getServletConfig in interface Servlet

Returns:

the ServletConfig object that initializes this servlet

See Also:

Servlet.init(javax.servlet.ServletConfig)

getServletInfo

public String getServletInfo()

Return information about this Servlet.

Specified by:

getServletInfo in interface Servlet

Returns:

a String containing servlet information

init

public void init(ServletConfig servletConfig)
          throws ServletException

Acquire the factory instances we will require.

Specified by:

init in interface Servlet

Parameters:

servletConfig - a ServletConfig object containing the servlet's configuration and initialization parameters

Throws:

ServletException - if, for any reason, the startup of this Faces application failed. This includes errors in the config file that is parsed before or during the processing of this init() method.

See Also:

UnavailableException, Servlet.getServletConfig()

service

public void service(ServletRequest req,
                    ServletResponse resp)
             throws IOException,
                    ServletException

Process an incoming request, and create the corresponding response according to the following specification.

If the request and response arguments to this method are not instances of HttpServletRequest and HttpServletResponse, respectively, the results of invoking this method are undefined.

This method must respond to requests that contain the following strings by invoking the sendError method on the response argument (cast to HttpServletResponse), passing the code HttpServletResponse.SC_NOT_FOUND as the argument.

/WEB-INF/
/WEB-INF
/META-INF/
/META-INF

If none of the cases described above in the specification for this method apply to the servicing of this request, the following action must be taken to service the request.

Acquire a FacesContext instance for this request.

Acquire the ResourceHandler for this request by calling Application.getResourceHandler(). Call ResourceHandler.isResourceRequest(javax.faces.context.FacesContext). If this returns true call ResourceHandler.handleResourceRequest(javax.faces.context.FacesContext). If this returns false, call Lifecycle.attachWindow(javax.faces.context.FacesContext) followed by Lifecycle.execute(javax.faces.context.FacesContext) followed by Lifecycle.render(javax.faces.context.FacesContext). If a FacesException is thrown in either case, extract the cause from the FacesException. If the cause is null extract the message from the FacesException, put it inside of a new ServletException instance, and pass the FacesException instance as the root cause, then rethrow the ServletException instance. If the cause is an instance of ServletException, rethrow the cause. If the cause is an instance of IOException, rethrow the cause. Otherwise, create a new ServletException instance, passing the message from the cause, as the first argument, and the cause itself as the second argument.

The implementation must make it so FacesContext.release() is called within a finally block as late as possible in the processing for the JSF related portion of this request.

Specified by:

service in interface Servlet

Parameters:

req - The servlet request we are processing

resp - The servlet response we are creating

Throws:

IOException - if an input/output error occurs during processing

ServletException - if a servlet error occurs during processing