javax.servlet
public interface RequestDispatcher
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.
Version: $Version$
See Also: ServletContext ServletContext
Method Summary | |
---|---|
void | forward(ServletRequest request, ServletResponse response)
Forwards a request from
a servlet to another resource (servlet, JSP file, or
HTML file) on the server. |
void | include(ServletRequest request, ServletResponse response)
Includes the content of a resource (servlet, JSP page,
HTML file) in 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.
Parameters: request a ServletRequest object that represents the request the client makes of the servlet response a ServletResponse object that represents the response the servlet returns to the client
Throws: ServletException if the target resource throws this exception IOException if the target resource throws this exception IllegalStateException if the response was already committed
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.
Parameters: request a ServletRequest object that contains the client's request response a ServletResponse object that contains the servlet's response
Throws: ServletException if the included resource throws this exception IOException if the included resource throws this exception