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Interface javax.servlet.RequestDispatcher
- public interface RequestDispatcher
Defines a object which serves as a wrapper around a server
resource accessible via a particular URL path. This interface
is primary used to access the functionality of one servlet
from another.
This class is not implemented by servlet programmers, but by
servlet engine authors.
- See Also:
- getRequestDispatcher
-
forward(ServletRequest, ServletResponse)
- Used for forwarding a request from one servlet to another
component within the server.
-
include(ServletRequest, ServletResponse)
- Includes the generated response from the target resource into
the current response.
forward
public abstract void forward(ServletRequest request,
ServletResponse response) throws ServletException, IOException
- Used for forwarding a request from one servlet to another
component within the server. This method is useful in cases
where one servlet does preliminary processing of a request
and wants to programmatically hand off the generation of a
response to another servlet.
This method may not be used if the calling servlet has
already output any response to the client.
- Parameters:
- request - the client's request on the servlet
- response - the client's response from the servlet
- Throws: ServletException
- if a servlet exception is thrown by the
target servlet
- Throws: IOException
- if an I/O Exception occurs
- Throws: IllegalStateException
- if the ServletOutputStream or a writer
had allready been obtained from the response object
include
public abstract void include(ServletRequest request,
ServletResponse response) throws ServletException, IOException
- Includes the generated response from the target resource into
the current response. This method allows for programmatic
server side includes.
The called servlet (or other resource) will only be able to
have access to the PrintWriter or OutputStream of the given request.
No headers may be set by the called resource. Any methods that
require access to response headers to properly function, such as
HttpServletRequest.getSession(), may not function properly when
used by a included resource.
- Parameters:
- request - the client's request on the servlet
- response - the client's response from the servlet
- Throws: ServletException
- if a servlet exception is thrown by the
target servlet
- Throws: IOException
- if the ServletOutputStream or a writer
had already been obtained from the response object
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