javax.servlet: public interface: RequestDispatcher

javax.servlet
public interface: RequestDispatcher [javadoc | source] Defines an object that receives requests from the client and sends them to any resource (such as a servlet, HTML file, or JSP file) on the server. The servlet container creates the RequestDispatcher object, which is used as a wrapper around a server resource located at a particular path or given by a particular name.

This interface is intended to wrap servlets, but a servlet container can create RequestDispatcher objects to wrap any type of resource.

Also see:

ServletContext#getRequestDispatcher(java.lang.String)

ServletContext#getNamedDispatcher(java.lang.String)

ServletRequest#getRequestDispatcher(java.lang.String)

author: Various -

version: $ - Version$

Method from javax.servlet.RequestDispatcher Summary:
forward, include

Method from javax.servlet.RequestDispatcher Detail:
public void forward(ServletRequest request, ServletResponse response) throws IOException, ServletException Forwards a request from a servlet to another resource (servlet, JSP file, or HTML file) on the server. This method allows one servlet to do preliminary processing of a request and another resource to generate the response. For a `RequestDispatcher` obtained via `getRequestDispatcher()`, the `ServletRequest` object has its path elements and parameters adjusted to match the path of the target resource. `forward` should be called before the response has been committed to the client (before response body output has been flushed). If the response already has been committed, this method throws an `IllegalStateException`. Uncommitted output in the response buffer is automatically cleared before the forward. The request and response parameters must be either the same objects as were passed to the calling servlet's service method or be subclasses of the ServletRequestWrapper or ServletResponseWrapper classes that wrap them.
public void include(ServletRequest request, ServletResponse response) throws IOException, ServletException Includes the content of a resource (servlet, JSP page, HTML file) in the response. In essence, this method enables programmatic server-side includes. The ServletResponse object has its path elements and parameters remain unchanged from the caller's. The included servlet cannot change the response status code or set headers; any attempt to make a change is ignored. The request and response parameters must be either the same objects as were passed to the calling servlet's service method or be subclasses of the ServletRequestWrapper or ServletResponseWrapper classes that wrap them.

Method from javax.servlet.RequestDispatcher Detail:

 public  void forward(ServletRequest request,
    ServletResponse response) throws IOException, ServletExceptionForwards a request from
a servlet to another resource (servlet, JSP file, or
HTML file) on the server. This method allows
one servlet to do preliminary processing of
a request and another resource to generate
the response.

For a RequestDispatcher obtained via
getRequestDispatcher(), the ServletRequest
object has its path elements and parameters adjusted to match
the path of the target resource.

forward should be called before the response has been
committed to the client (before response body output has been flushed).
If the response already has been committed, this method throws
an IllegalStateException.
Uncommitted output in the response buffer is automatically cleared
before the forward.

The request and response parameters must be either the same
objects as were passed to the calling servlet's service method or be
subclasses of the ServletRequestWrapper  or ServletResponseWrapper  classes
that wrap them.

 public  void include(ServletRequest request,
    ServletResponse response) throws IOException, ServletExceptionIncludes the content of a resource (servlet, JSP page,
HTML file) in the response. In essence, this method enables
programmatic server-side includes.

The ServletResponse  object has its path elements
and parameters remain unchanged from the caller's. The included
servlet cannot change the response status code or set headers;
any attempt to make a change is ignored.

The request and response parameters must be either the same
objects as were passed to the calling servlet's service method or be
subclasses of the ServletRequestWrapper  or ServletResponseWrapper  classes
that wrap them.