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.
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Field SummaryFieldsModifier and TypeFieldDescriptionstatic final StringThe name of the request attribute that should be set by the container when custom error-handling servlet or JSP page is invoked.static final StringThe name of the request attribute that should be set by the container when custom error-handling servlet or JSP page is invoked.static final StringThe name of the request attribute that should be set by the container when custom error-handling servlet or JSP page is invoked.static final StringThe name of the request attribute that should be set by the container when custom error-handling servlet or JSP page is invoked.static final StringThe name of the request attribute that should be set by the container when custom error-handling servlet or JSP page is invoked.static final StringThe name of the request attribute that should be set by the container when custom error-handling servlet or JSP page is invoked.static final StringThe name of the request attribute that should be set by the container when theforward(ServletRequest, ServletResponse)method is called.static final StringThe name of the request attribute that should be set by the container when theforward(ServletRequest, ServletResponse)method is called.static final StringThe name of the request attribute that should be set by the container when theforward(ServletRequest, ServletResponse)method is called.static final StringThe name of the request attribute that should be set by the container when theforward(ServletRequest, ServletResponse)method is called.static final StringThe name of the request attribute that should be set by the container when theforward(ServletRequest, ServletResponse)method is called.static final StringThe name of the request attribute that should be set by the container when theforward(ServletRequest, ServletResponse)method is called.static final StringThe name of the request attribute that should be set by the container when theinclude(ServletRequest, ServletResponse)method is called on theRequestDispatcherobtained by a path and not by a name.static final StringThe name of the request attribute that should be set by the container when theinclude(ServletRequest, ServletResponse)method is called on theRequestDispatcherobtained by a path and not by a name.static final StringThe name of the request attribute that should be set by the container when theinclude(ServletRequest, ServletResponse)method is called on theRequestDispatcherobtained by a path and not by a name.static final StringThe name of the request attribute that should be set by the container when theinclude(ServletRequest, ServletResponse)method is called on theRequestDispatcherobtained by a path and not by a name.static final StringThe name of the request attribute that should be set by the container when theinclude(ServletRequest, ServletResponse)method is called on theRequestDispatcherobtained by a path and not by a name.static final StringThe name of the request attribute that should be set by the container when theinclude(ServletRequest, ServletResponse)method is called on theRequestDispatcherobtained by a path and not by a name.
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Method SummaryModifier and TypeMethodDescriptionvoidforward(ServletRequest request, ServletResponse response) Forwards a request from a servlet to another resource (servlet, JSP file, or HTML file) on the server.voidinclude(ServletRequest request, ServletResponse response) Includes the content of a resource (servlet, JSP page, HTML file) in the response.
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Field Details- 
FORWARD_REQUEST_URIThe name of the request attribute that should be set by the container when theforward(ServletRequest, ServletResponse)method is called. It provides the original value of a path-related property of the request. See the chapter "Forwarded Request Parameters" in the Servlet Specification for details.- Since:
- Servlet 3.0
- See Also:
 
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FORWARD_CONTEXT_PATHThe name of the request attribute that should be set by the container when theforward(ServletRequest, ServletResponse)method is called. It provides the original value of a path-related property of the request. See the chapter "Forwarded Request Parameters" in the Servlet Specification for details.- Since:
- Servlet 3.0
- See Also:
 
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FORWARD_MAPPINGThe name of the request attribute that should be set by the container when theforward(ServletRequest, ServletResponse)method is called. It provides the original value of a path-related property of the request. See the chapter "Forwarded Request Parameters" in the Servlet Specification for details.- Since:
- Servlet 4.0
- See Also:
 
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FORWARD_PATH_INFOThe name of the request attribute that should be set by the container when theforward(ServletRequest, ServletResponse)method is called. It provides the original value of a path-related property of the request. See the chapter "Forwarded Request Parameters" in the Servlet Specification for details.- Since:
- Servlet 3.0
- See Also:
 
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FORWARD_SERVLET_PATHThe name of the request attribute that should be set by the container when theforward(ServletRequest, ServletResponse)method is called. It provides the original value of a path-related property of the request. See the chapter "Forwarded Request Parameters" in the Servlet Specification for details.- Since:
- Servlet 3.0
- See Also:
 
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FORWARD_QUERY_STRINGThe name of the request attribute that should be set by the container when theforward(ServletRequest, ServletResponse)method is called. It provides the original value of a path-related property of the request. See the chapter "Forwarded Request Parameters" in the Servlet Specification for details.- Since:
- Servlet 3.0
- See Also:
 
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INCLUDE_REQUEST_URIThe name of the request attribute that should be set by the container when theinclude(ServletRequest, ServletResponse)method is called on theRequestDispatcherobtained by a path and not by a name. It provides information on the path that was used to obtain theRequestDispatcherinstance for this include call. See the chapter "Included Request Parameters" in the Servlet Specification for details.- Since:
- Servlet 3.0
- See Also:
 
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INCLUDE_CONTEXT_PATHThe name of the request attribute that should be set by the container when theinclude(ServletRequest, ServletResponse)method is called on theRequestDispatcherobtained by a path and not by a name. It provides information on the path that was used to obtain theRequestDispatcherinstance for this include call. See the chapter "Included Request Parameters" in the Servlet Specification for details.- Since:
- Servlet 3.0
- See Also:
 
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INCLUDE_PATH_INFOThe name of the request attribute that should be set by the container when theinclude(ServletRequest, ServletResponse)method is called on theRequestDispatcherobtained by a path and not by a name. It provides information on the path that was used to obtain theRequestDispatcherinstance for this include call. See the chapter "Included Request Parameters" in the Servlet Specification for details.- Since:
- Servlet 3.0
- See Also:
 
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INCLUDE_MAPPINGThe name of the request attribute that should be set by the container when theinclude(ServletRequest, ServletResponse)method is called on theRequestDispatcherobtained by a path and not by a name. It provides information on the path that was used to obtain theRequestDispatcherinstance for this include call. See the chapter "Included Request Parameters" in the Servlet Specification for details.- Since:
- Servlet 4.0
- See Also:
 
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INCLUDE_SERVLET_PATHThe name of the request attribute that should be set by the container when theinclude(ServletRequest, ServletResponse)method is called on theRequestDispatcherobtained by a path and not by a name. It provides information on the path that was used to obtain theRequestDispatcherinstance for this include call. See the chapter "Included Request Parameters" in the Servlet Specification for details.- Since:
- Servlet 3.0
- See Also:
 
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INCLUDE_QUERY_STRINGThe name of the request attribute that should be set by the container when theinclude(ServletRequest, ServletResponse)method is called on theRequestDispatcherobtained by a path and not by a name. It provides information on the path that was used to obtain theRequestDispatcherinstance for this include call. See the chapter "Included Request Parameters" in the Servlet Specification for details.- Since:
- Servlet 3.0
- See Also:
 
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ERROR_EXCEPTIONThe name of the request attribute that should be set by the container when custom error-handling servlet or JSP page is invoked. The value of the attribute is of typejava.lang.Throwable. See the chapter "Error Handling" in the Servlet Specification for details.- Since:
- Servlet 3.0
- See Also:
 
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ERROR_EXCEPTION_TYPEThe name of the request attribute that should be set by the container when custom error-handling servlet or JSP page is invoked. The value of the attribute is of typejava.lang.Class. See the chapter "Error Handling" in the Servlet Specification for details.- Since:
- Servlet 3.0
- See Also:
 
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ERROR_MESSAGEThe name of the request attribute that should be set by the container when custom error-handling servlet or JSP page is invoked. The value of the attribute is of typeString. See the chapter "Error Handling" in the Servlet Specification for details.- Since:
- Servlet 3.0
- See Also:
 
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ERROR_REQUEST_URIThe name of the request attribute that should be set by the container when custom error-handling servlet or JSP page is invoked. The value of the attribute is of typeString. See the chapter "Error Handling" in the Servlet Specification for details.- Since:
- Servlet 3.0
- See Also:
 
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ERROR_SERVLET_NAMEThe name of the request attribute that should be set by the container when custom error-handling servlet or JSP page is invoked. The value of the attribute is of typeString. See the chapter "Error Handling" in the Servlet Specification for details.- Since:
- Servlet 3.0
- See Also:
 
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ERROR_STATUS_CODEThe name of the request attribute that should be set by the container when custom error-handling servlet or JSP page is invoked. The value of the attribute is of typejava.lang.Integer. See the chapter "Error Handling" in the Servlet Specification for details.- Since:
- Servlet 3.0
- See Also:
 
 
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Method Details- 
forwardForwards 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 RequestDispatcherobtained viagetRequestDispatcher(), theServletRequestobject has its path elements and parameters adjusted to match the path of the target resource.forwardshould 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 anIllegalStateException. 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 ServletRequestWrapperorServletResponseWrapperclasses that wrap them.- Parameters:
- request- a- ServletRequestobject that represents the request the client makes of the servlet
- response- a- ServletResponseobject 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
 
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includeIncludes the content of a resource (servlet, JSP page, HTML file) in the response. In essence, this method enables programmatic server-side includes.The ServletResponseobject 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 ServletRequestWrapperorServletResponseWrapperclasses that wrap them.- Parameters:
- request- a- ServletRequestobject that contains the client's request
- response- a- ServletResponseobject that contains the servlet's response
- Throws:
- ServletException- if the included resource throws this exception
- IOException- if the included resource throws this exception
 
 
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