Package javax.servlet

Interface RequestDispatcher

    • Field Detail

      • FORWARD_REQUEST_URI

        static final String FORWARD_REQUEST_URI
        The name of the request attribute under which the original request URI is made available to the target of a forward
        See Also:
        Constant Field Values
      • FORWARD_CONTEXT_PATH

        static final String FORWARD_CONTEXT_PATH
        The name of the request attribute under which the original context path is made available to the target of a forward
        See Also:
        Constant Field Values
      • FORWARD_PATH_INFO

        static final String FORWARD_PATH_INFO
        The name of the request attribute under which the original path info is made available to the target of a forward
        See Also:
        Constant Field Values
      • FORWARD_SERVLET_PATH

        static final String FORWARD_SERVLET_PATH
        The name of the request attribute under which the original servlet path is made available to the target of a forward
        See Also:
        Constant Field Values
      • FORWARD_QUERY_STRING

        static final String FORWARD_QUERY_STRING
        The name of the request attribute under which the original query string is made available to the target of a forward
        See Also:
        Constant Field Values
      • INCLUDE_REQUEST_URI

        static final String INCLUDE_REQUEST_URI
        The name of the request attribute under which the request URI of the target of an include is stored
        See Also:
        Constant Field Values
      • INCLUDE_CONTEXT_PATH

        static final String INCLUDE_CONTEXT_PATH
        The name of the request attribute under which the context path of the target of an include is stored
        See Also:
        Constant Field Values
      • INCLUDE_PATH_INFO

        static final String INCLUDE_PATH_INFO
        The name of the request attribute under which the path info of the target of an include is stored
        See Also:
        Constant Field Values
      • INCLUDE_SERVLET_PATH

        static final String INCLUDE_SERVLET_PATH
        The name of the request attribute under which the servlet path of the target of an include is stored
        See Also:
        Constant Field Values
      • INCLUDE_QUERY_STRING

        static final String INCLUDE_QUERY_STRING
        The name of the request attribute under which the query string of the target of an include is stored
        See Also:
        Constant Field Values
      • ERROR_EXCEPTION

        static final String ERROR_EXCEPTION
        The name of the request attribute under which the exception object is propagated during an error dispatch
        See Also:
        Constant Field Values
      • ERROR_EXCEPTION_TYPE

        static final String ERROR_EXCEPTION_TYPE
        The name of the request attribute under which the type of the exception object is propagated during an error dispatch
        See Also:
        Constant Field Values
      • ERROR_MESSAGE

        static final String ERROR_MESSAGE
        The name of the request attribute under which the exception message is propagated during an error dispatch
        See Also:
        Constant Field Values
      • ERROR_REQUEST_URI

        static final String ERROR_REQUEST_URI
        The name of the request attribute under which the request URI whose processing caused the error is propagated during an error dispatch
        See Also:
        Constant Field Values
      • ERROR_SERVLET_NAME

        static final String ERROR_SERVLET_NAME
        The name of the request attribute under which the name of the servlet in which the error occurred is propagated during an error dispatch
        See Also:
        Constant Field Values
      • ERROR_STATUS_CODE

        static final String ERROR_STATUS_CODE
        The name of the request attribute under which the response status is propagated during an error dispatch
        See Also:
        Constant Field Values
    • Method Detail

      • forward

        void forward​(ServletRequest request,
                     ServletResponse response)
              throws ServletException,
                     IOException
        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.

        This method sets the dispatcher type of the given request to DispatcherType.FORWARD.

        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
        See Also:
        ServletRequest.getDispatcherType()
      • include

        void include​(ServletRequest request,
                     ServletResponse response)
              throws ServletException,
                     IOException
        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.

        This method sets the dispatcher type of the given request to DispatcherType.INCLUDE.

        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
        See Also:
        ServletRequest.getDispatcherType()