Package javax.servlet.http

Interface HttpServletResponse

All Superinterfaces:
ServletResponse
All Known Implementing Classes:
HttpServletResponseWrapper
public interface HttpServletResponse extends ServletResponse
Extends the ServletResponse interface to provide HTTP-specific functionality in sending a response. For example, it has methods to access HTTP headers and cookies.

The servlet container creates an HttpServletResponse object and passes it as an argument to the servlet's service methods (doGet, doPost, etc).

See Also:

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final int
    SC_ACCEPTED
    Status code (202) indicating that a request was accepted for processing, but was not completed.
    static final int
    SC_BAD_GATEWAY
    Status code (502) indicating that the HTTP server received an invalid response from a server it consulted when acting as a proxy or gateway.
    static final int
    SC_BAD_REQUEST
    Status code (400) indicating the request sent by the client was syntactically incorrect.
    static final int
    SC_CONFLICT
    Status code (409) indicating that the request could not be completed due to a conflict with the current state of the resource.
    static final int
    SC_CONTINUE
    Status code (100) indicating the client can continue.
    static final int
    SC_CREATED
    Status code (201) indicating the request succeeded and created a new resource on the server.
    static final int
    SC_EXPECTATION_FAILED
    Status code (417) indicating that the server could not meet the expectation given in the Expect request header.
    static final int
    SC_FORBIDDEN
    Status code (403) indicating the server understood the request but refused to fulfill it.
    static final int
    SC_FOUND
    Status code (302) indicating that the resource reside temporarily under a different URI.
    static final int
    SC_GATEWAY_TIMEOUT
    Status code (504) indicating that the server did not receive a timely response from the upstream server while acting as a gateway or proxy.
    static final int
    SC_GONE
    Status code (410) indicating that the resource is no longer available at the server and no forwarding address is known.
    static final int
    SC_HTTP_VERSION_NOT_SUPPORTED
    Status code (505) indicating that the server does not support or refuses to support the HTTP protocol version that was used in the request message.
    static final int
    SC_INTERNAL_SERVER_ERROR
    Status code (500) indicating an error inside the HTTP server which prevented it from fulfilling the request.
    static final int
    SC_LENGTH_REQUIRED
    Status code (411) indicating that the request cannot be handled without a defined Content-Length.
    static final int
    SC_METHOD_NOT_ALLOWED
    Status code (405) indicating that the method specified in the Request-Line is not allowed for the resource identified by the Request-URI.
    static final int
    SC_MOVED_PERMANENTLY
    Status code (301) indicating that the resource has permanently moved to a new location, and that future references should use a new URI with their requests.
    static final int
    SC_MOVED_TEMPORARILY
    Status code (302) indicating that the resource has temporarily moved to another location, but that future references should still use the original URI to access the resource.
    static final int
    SC_MULTIPLE_CHOICES
    Status code (300) indicating that the requested resource corresponds to any one of a set of representations, each with its own specific location.
    static final int
    SC_NO_CONTENT
    Status code (204) indicating that the request succeeded but that there was no new information to return.
    static final int
    SC_NON_AUTHORITATIVE_INFORMATION
    Status code (203) indicating that the meta information presented by the client did not originate from the server.
    static final int
    SC_NOT_ACCEPTABLE
    Status code (406) indicating that the resource identified by the request is only capable of generating response entities which have content characteristics not acceptable according to the accept headers sent in the request.
    static final int
    SC_NOT_FOUND
    Status code (404) indicating that the requested resource is not available.
    static final int
    SC_NOT_IMPLEMENTED
    Status code (501) indicating the HTTP server does not support the functionality needed to fulfill the request.
    static final int
    SC_NOT_MODIFIED
    Status code (304) indicating that a conditional GET operation found that the resource was available and not modified.
    static final int
    SC_OK
    Status code (200) indicating the request succeeded normally.
    static final int
    SC_PARTIAL_CONTENT
    Status code (206) indicating that the server has fulfilled the partial GET request for the resource.
    static final int
    SC_PAYMENT_REQUIRED
    Status code (402) reserved for future use.
    static final int
    SC_PRECONDITION_FAILED
    Status code (412) indicating that the precondition given in one or more of the request-header fields evaluated to false when it was tested on the server.
    static final int
    SC_PROXY_AUTHENTICATION_REQUIRED
    Status code (407) indicating that the client MUST first authenticate itself with the proxy.
    static final int
    SC_REQUEST_ENTITY_TOO_LARGE
    Status code (413) indicating that the server is refusing to process the request because the request entity is larger than the server is willing or able to process.
    static final int
    SC_REQUEST_TIMEOUT
    Status code (408) indicating that the client did not produce a request within the time that the server was prepared to wait.
    static final int
    SC_REQUEST_URI_TOO_LONG
    Status code (414) indicating that the server is refusing to service the request because the Request-URI is longer than the server is willing to interpret.
    static final int
    SC_REQUESTED_RANGE_NOT_SATISFIABLE
    Status code (416) indicating that the server cannot serve the requested byte range.
    static final int
    SC_RESET_CONTENT
    Status code (205) indicating that the agent SHOULD reset the document view which caused the request to be sent.
    static final int
    SC_SEE_OTHER
    Status code (303) indicating that the response to the request can be found under a different URI.
    static final int
    SC_SERVICE_UNAVAILABLE
    Status code (503) indicating that the HTTP server is temporarily overloaded, and unable to handle the request.
    static final int
    SC_SWITCHING_PROTOCOLS
    Status code (101) indicating the server is switching protocols according to Upgrade header.
    static final int
    SC_TEMPORARY_REDIRECT
    Status code (307) indicating that the requested resource resides temporarily under a different URI.
    static final int
    SC_UNAUTHORIZED
    Status code (401) indicating that the request requires HTTP authentication.
    static final int
    SC_UNSUPPORTED_MEDIA_TYPE
    Status code (415) indicating that the server is refusing to service the request because the entity of the request is in a format not supported by the requested resource for the requested method.
    static final int
    SC_USE_PROXY
    Status code (305) indicating that the requested resource MUST be accessed through the proxy given by the Location field.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    addCookie(Cookie cookie)
    Adds the specified cookie to the response.
    void
    addDateHeader(String name, long date)
    Adds a response header with the given name and date-value.
    void
    addHeader(String name, String value)
    Adds a response header with the given name and value.
    void
    addIntHeader(String name, int value)
    Adds a response header with the given name and integer value.
    boolean
    containsHeader(String name)
    Returns a boolean indicating whether the named response header has already been set.
    String
    encodeRedirectUrl(String url)
    Deprecated.
    As of version 2.1, use encodeRedirectURL(String url) instead
    String
    encodeRedirectURL(String url)
    Encodes the specified URL for use in the sendRedirect method or, if encoding is not needed, returns the URL unchanged.
    String
    encodeUrl(String url)
    Deprecated.
    As of version 2.1, use encodeURL(String url) instead
    String
    encodeURL(String url)
    Encodes the specified URL by including the session ID in it, or, if encoding is not needed, returns the URL unchanged.
    String
    getHeader(String name)
    Return the value for the specified header, or null if this header has not been set.
    Collection<String>
    getHeaderNames()
    Get the header names set for this HTTP response.
    Collection<String>
    getHeaders(String name)
    Return a Collection of all the header values associated with the specified header name.
    int
    getStatus()
    Get the HTTP status code for this Response.
    default Supplier<Map<String,String>>
    getTrailerFields()
    Obtain the supplier of the trailer headers.
    void
    sendError(int sc)
    Sends an error response to the client using the specified status code and clears the buffer.
    void
    sendError(int sc, String msg)
    Sends an error response to the client using the specified status code and clears the output buffer.
    void
    sendRedirect(String location)
    Sends a redirect response to the client using the specified redirect location URL with the status code SC_FOUND 302 (Found), clears the response buffer and commits the response.
    void
    setDateHeader(String name, long date)
    Sets a response header with the given name and date-value.
    void
    setHeader(String name, String value)
    Sets a response header with the given name and value.
    void
    setIntHeader(String name, int value)
    Sets a response header with the given name and integer value.
    void
    setStatus(int sc)
    Sets the status code for this response.
    void
    setStatus(int sc, String sm)
    Deprecated.
    As of version 2.1, due to ambiguous meaning of the message parameter.
    default void
    setTrailerFields(Supplier<Map<String,String>> supplier)
    Configure the supplier of the trailer headers.

    Methods inherited from interface javax.servlet.ServletResponse

    flushBuffer, getBufferSize, getCharacterEncoding, getContentType, getLocale, getOutputStream, getWriter, isCommitted, reset, resetBuffer, setBufferSize, setCharacterEncoding, setContentLength, setContentLengthLong, setContentType, setLocale

  • Field Details

    • SC_CONTINUE

      static final int SC_CONTINUE
      Status code (100) indicating the client can continue.
      See Also:

    • SC_SWITCHING_PROTOCOLS

      static final int SC_SWITCHING_PROTOCOLS
      Status code (101) indicating the server is switching protocols according to Upgrade header.
      See Also:

    • SC_OK

      static final int SC_OK
      Status code (200) indicating the request succeeded normally.
      See Also:

    • SC_CREATED

      static final int SC_CREATED
      Status code (201) indicating the request succeeded and created a new resource on the server.
      See Also:

    • SC_ACCEPTED

      static final int SC_ACCEPTED
      Status code (202) indicating that a request was accepted for processing, but was not completed.
      See Also:

    • SC_NON_AUTHORITATIVE_INFORMATION

      static final int SC_NON_AUTHORITATIVE_INFORMATION
      Status code (203) indicating that the meta information presented by the client did not originate from the server.
      See Also:

    • SC_NO_CONTENT

      static final int SC_NO_CONTENT
      Status code (204) indicating that the request succeeded but that there was no new information to return.
      See Also:

    • SC_RESET_CONTENT

      static final int SC_RESET_CONTENT
      Status code (205) indicating that the agent SHOULD reset the document view which caused the request to be sent.
      See Also:

    • SC_PARTIAL_CONTENT

      static final int SC_PARTIAL_CONTENT
      Status code (206) indicating that the server has fulfilled the partial GET request for the resource.
      See Also:

    • SC_MULTIPLE_CHOICES

      static final int SC_MULTIPLE_CHOICES
      Status code (300) indicating that the requested resource corresponds to any one of a set of representations, each with its own specific location.
      See Also:

    • SC_MOVED_PERMANENTLY

      static final int SC_MOVED_PERMANENTLY
      Status code (301) indicating that the resource has permanently moved to a new location, and that future references should use a new URI with their requests.
      See Also:

    • SC_MOVED_TEMPORARILY

      static final int SC_MOVED_TEMPORARILY
      Status code (302) indicating that the resource has temporarily moved to another location, but that future references should still use the original URI to access the resource. This definition is being retained for backwards compatibility. SC_FOUND is now the preferred definition.
      See Also:

    • SC_FOUND

      static final int SC_FOUND
      Status code (302) indicating that the resource reside temporarily under a different URI. Since the redirection might be altered on occasion, the client should continue to use the Request-URI for future requests.(HTTP/1.1) To represent the status code (302), it is recommended to use this variable.
      See Also:

    • SC_SEE_OTHER

      static final int SC_SEE_OTHER
      Status code (303) indicating that the response to the request can be found under a different URI.
      See Also:

    • SC_NOT_MODIFIED

      static final int SC_NOT_MODIFIED
      Status code (304) indicating that a conditional GET operation found that the resource was available and not modified.
      See Also:

    • SC_USE_PROXY

      static final int SC_USE_PROXY
      Status code (305) indicating that the requested resource MUST be accessed through the proxy given by the Location field.
      See Also:

    • SC_TEMPORARY_REDIRECT

      static final int SC_TEMPORARY_REDIRECT
      Status code (307) indicating that the requested resource resides temporarily under a different URI. The temporary URI SHOULD be given by the Location field in the response.
      See Also:

    • SC_BAD_REQUEST

      static final int SC_BAD_REQUEST
      Status code (400) indicating the request sent by the client was syntactically incorrect.
      See Also:

    • SC_UNAUTHORIZED

      static final int SC_UNAUTHORIZED
      Status code (401) indicating that the request requires HTTP authentication.
      See Also:

    • SC_PAYMENT_REQUIRED

      static final int SC_PAYMENT_REQUIRED
      Status code (402) reserved for future use.
      See Also:

    • SC_FORBIDDEN

      static final int SC_FORBIDDEN
      Status code (403) indicating the server understood the request but refused to fulfill it.
      See Also:

    • SC_NOT_FOUND

      static final int SC_NOT_FOUND
      Status code (404) indicating that the requested resource is not available.
      See Also:

    • SC_METHOD_NOT_ALLOWED

      static final int SC_METHOD_NOT_ALLOWED
      Status code (405) indicating that the method specified in the Request-Line is not allowed for the resource identified by the Request-URI.
      See Also:

    • SC_NOT_ACCEPTABLE

      static final int SC_NOT_ACCEPTABLE
      Status code (406) indicating that the resource identified by the request is only capable of generating response entities which have content characteristics not acceptable according to the accept headers sent in the request.
      See Also:

    • SC_PROXY_AUTHENTICATION_REQUIRED

      static final int SC_PROXY_AUTHENTICATION_REQUIRED
      Status code (407) indicating that the client MUST first authenticate itself with the proxy.
      See Also:

    • SC_REQUEST_TIMEOUT

      static final int SC_REQUEST_TIMEOUT
      Status code (408) indicating that the client did not produce a request within the time that the server was prepared to wait.
      See Also:

    • SC_CONFLICT

      static final int SC_CONFLICT
      Status code (409) indicating that the request could not be completed due to a conflict with the current state of the resource.
      See Also:

    • SC_GONE

      static final int SC_GONE
      Status code (410) indicating that the resource is no longer available at the server and no forwarding address is known. This condition SHOULD be considered permanent.
      See Also:

    • SC_LENGTH_REQUIRED

      static final int SC_LENGTH_REQUIRED
      Status code (411) indicating that the request cannot be handled without a defined Content-Length.
      See Also:

    • SC_PRECONDITION_FAILED

      static final int SC_PRECONDITION_FAILED
      Status code (412) indicating that the precondition given in one or more of the request-header fields evaluated to false when it was tested on the server.
      See Also:

    • SC_REQUEST_ENTITY_TOO_LARGE

      static final int SC_REQUEST_ENTITY_TOO_LARGE
      Status code (413) indicating that the server is refusing to process the request because the request entity is larger than the server is willing or able to process.
      See Also:

    • SC_REQUEST_URI_TOO_LONG

      static final int SC_REQUEST_URI_TOO_LONG
      Status code (414) indicating that the server is refusing to service the request because the Request-URI is longer than the server is willing to interpret.
      See Also:

    • SC_UNSUPPORTED_MEDIA_TYPE

      static final int SC_UNSUPPORTED_MEDIA_TYPE
      Status code (415) indicating that the server is refusing to service the request because the entity of the request is in a format not supported by the requested resource for the requested method.
      See Also:

    • SC_REQUESTED_RANGE_NOT_SATISFIABLE

      static final int SC_REQUESTED_RANGE_NOT_SATISFIABLE
      Status code (416) indicating that the server cannot serve the requested byte range.
      See Also:

    • SC_EXPECTATION_FAILED

      static final int SC_EXPECTATION_FAILED
      Status code (417) indicating that the server could not meet the expectation given in the Expect request header.
      See Also:

    • SC_INTERNAL_SERVER_ERROR

      static final int SC_INTERNAL_SERVER_ERROR
      Status code (500) indicating an error inside the HTTP server which prevented it from fulfilling the request.
      See Also:

    • SC_NOT_IMPLEMENTED

      static final int SC_NOT_IMPLEMENTED
      Status code (501) indicating the HTTP server does not support the functionality needed to fulfill the request.
      See Also:

    • SC_BAD_GATEWAY

      static final int SC_BAD_GATEWAY
      Status code (502) indicating that the HTTP server received an invalid response from a server it consulted when acting as a proxy or gateway.
      See Also:

    • SC_SERVICE_UNAVAILABLE

      static final int SC_SERVICE_UNAVAILABLE
      Status code (503) indicating that the HTTP server is temporarily overloaded, and unable to handle the request.
      See Also:

    • SC_GATEWAY_TIMEOUT

      static final int SC_GATEWAY_TIMEOUT
      Status code (504) indicating that the server did not receive a timely response from the upstream server while acting as a gateway or proxy.
      See Also:

    • SC_HTTP_VERSION_NOT_SUPPORTED

      static final int SC_HTTP_VERSION_NOT_SUPPORTED
      Status code (505) indicating that the server does not support or refuses to support the HTTP protocol version that was used in the request message.
      See Also:

  • Method Details

    • addCookie

      void addCookie(Cookie cookie)
      Adds the specified cookie to the response. This method can be called multiple times to set more than one cookie.
      Parameters:
      cookie - the Cookie to return to the client

    • containsHeader

      boolean containsHeader(String name)
      Returns a boolean indicating whether the named response header has already been set.
      Parameters:
      name - the header name
      Returns:
      true if the named response header has already been set; false otherwise

    • encodeURL

      String encodeURL(String url)
      Encodes the specified URL by including the session ID in it, or, if encoding is not needed, returns the URL unchanged. The implementation of this method includes the logic to determine whether the session ID needs to be encoded in the URL. For example, if the browser supports cookies, or session tracking is turned off, URL encoding is unnecessary.

      For robust session tracking, all URLs emitted by a servlet should be run through this method. Otherwise, URL rewriting cannot be used with browsers which do not support cookies.

      Parameters:
      url - the url to be encoded.
      Returns:
      the encoded URL if encoding is needed; the unchanged URL otherwise.

    • encodeRedirectURL

      String encodeRedirectURL(String url)
      Encodes the specified URL for use in the sendRedirect method or, if encoding is not needed, returns the URL unchanged. The implementation of this method includes the logic to determine whether the session ID needs to be encoded in the URL. Because the rules for making this determination can differ from those used to decide whether to encode a normal link, this method is separated from the encodeURL method.

      All URLs sent to the HttpServletResponse.sendRedirect method should be run through this method. Otherwise, URL rewriting cannot be used with browsers which do not support cookies.

      Parameters:
      url - the url to be encoded.
      Returns:
      the encoded URL if encoding is needed; the unchanged URL otherwise.
      See Also:

    • encodeUrl

      @Deprecated String encodeUrl(String url)
      Deprecated.
      As of version 2.1, use encodeURL(String url) instead
      Parameters:
      url - the url to be encoded.
      Returns:
      the encoded URL if encoding is needed; the unchanged URL otherwise.

    • encodeRedirectUrl

      @Deprecated String encodeRedirectUrl(String url)
      Deprecated.
      As of version 2.1, use encodeRedirectURL(String url) instead
      Parameters:
      url - the url to be encoded.
      Returns:
      the encoded URL if encoding is needed; the unchanged URL otherwise.

    • sendError

      void sendError(int sc, String msg) throws IOException
      Sends an error response to the client using the specified status code and clears the output buffer. The server defaults to creating the response to look like an HTML-formatted server error page containing the specified message, setting the content type to "text/html", leaving cookies and other headers unmodified. If an error-page declaration has been made for the web application corresponding to the status code passed in, it will be served back in preference to the suggested msg parameter.

      If the response has already been committed, this method throws an IllegalStateException. After using this method, the response should be considered to be committed and should not be written to.

      Parameters:
      sc - the error status code
      msg - the descriptive message
      Throws:
      IOException - If an input or output exception occurs
      IllegalStateException - If the response was committed

    • sendError

      void sendError(int sc) throws IOException
      Sends an error response to the client using the specified status code and clears the buffer. This is equivalent to calling sendError(int, String) with the same status code and null for the message.
      Parameters:
      sc - the error status code
      Throws:
      IOException - If an input or output exception occurs
      IllegalStateException - If the response was committed before this method call

    • sendRedirect

      void sendRedirect(String location) throws IOException
      Sends a redirect response to the client using the specified redirect location URL with the status code SC_FOUND 302 (Found), clears the response buffer and commits the response. The response buffer will be replaced with a short hypertext note as per RFC 9110.

      This method has no effect if called from an include.

      This method accepts both relative and absolute URLs. Absolute URLs passed to this method are used as provided as the redirect location URL. Relative URLs are converted to absolute URLs. If converting a relative URL to an absolute URL then:

      • If the location is relative without a leading '/' the container interprets it as relative to the current request URI.
      • If the location is relative with a leading '/' the container interprets it as relative to the servlet container root.
      • If the location is relative with two leading '/' the container interprets it as a network-path reference (see RFC 3986: Uniform Resource Identifier (URI): Generic Syntax, section 4.2 "Relative Reference").

      If the response has already been committed, this method throws an IllegalStateException. After using this method, the response should be considered to be committed and should not be written to.

      Parameters:
      location - the redirect location URL (may be absolute or relative)
      Throws:
      IOException - If an input or output exception occurs
      IllegalArgumentException - If a relative URL is given and cannot be converted into an absolute URL
      IllegalStateException - If the response was already committed when this method was called

    • setDateHeader

      void setDateHeader(String name, long date)
      Sets a response header with the given name and date-value. The date is specified in terms of milliseconds since the epoch. If the header had already been set, the new value overwrites the previous one. The containsHeader method can be used to test for the presence of a header before setting its value.
      Parameters:
      name - the name of the header to set
      date - the assigned date value
      See Also:

    • addDateHeader

      void addDateHeader(String name, long date)
      Adds a response header with the given name and date-value. The date is specified in terms of milliseconds since the epoch. This method allows response headers to have multiple values.
      Parameters:
      name - the name of the header to set
      date - the additional date value
      See Also:

    • setHeader

      void setHeader(String name, String value)
      Sets a response header with the given name and value. If the header had already been set, the new value overwrites the previous one. The containsHeader method can be used to test for the presence of a header before setting its value.
      Parameters:
      name - the name of the header
      value - the header value If it contains octet string, it should be encoded according to RFC 2047 (http://www.ietf.org/rfc/rfc2047.txt)
      See Also:

    • addHeader

      void addHeader(String name, String value)
      Adds a response header with the given name and value. This method allows response headers to have multiple values.
      Parameters:
      name - the name of the header
      value - the additional header value If it contains octet string, it should be encoded according to RFC 2047 (http://www.ietf.org/rfc/rfc2047.txt)
      See Also:

    • setIntHeader

      void setIntHeader(String name, int value)
      Sets a response header with the given name and integer value. If the header had already been set, the new value overwrites the previous one. The containsHeader method can be used to test for the presence of a header before setting its value.
      Parameters:
      name - the name of the header
      value - the assigned integer value
      See Also:

    • addIntHeader

      void addIntHeader(String name, int value)
      Adds a response header with the given name and integer value. This method allows response headers to have multiple values.
      Parameters:
      name - the name of the header
      value - the assigned integer value
      See Also:

    • setStatus

      void setStatus(int sc)
      Sets the status code for this response. This method is used to set the return status code when there is no error (for example, for the status codes SC_OK or SC_MOVED_TEMPORARILY). If there is an error, and the caller wishes to invoke an error-page defined in the web application, the sendError method should be used instead.

      The container clears the buffer and sets the Location header, preserving cookies and other headers.

      Parameters:
      sc - the status code
      See Also:

    • setStatus

      @Deprecated void setStatus(int sc, String sm)
      Deprecated.
      As of version 2.1, due to ambiguous meaning of the message parameter. To set a status code use setStatus(int), to send an error with a description use sendError(int, String).
      Sets the status code and message for this response.
      Parameters:
      sc - the status code
      sm - the status message

    • getStatus

      int getStatus()
      Get the HTTP status code for this Response.
      Returns:
      The HTTP status code for this Response
      Since:
      Servlet 3.0

    • getHeader

      String getHeader(String name)
      Return the value for the specified header, or null if this header has not been set. If more than one value was added for this name, only the first is returned; use getHeaders(String) to retrieve all of them.
      Parameters:
      name - Header name to look up
      Returns:
      The first value for the specified header. This is the raw value so if multiple values are specified in the first header then they will be returned as a single header value .
      Since:
      Servlet 3.0

    • getHeaders

      Collection<String> getHeaders(String name)
      Return a Collection of all the header values associated with the specified header name.
      Parameters:
      name - Header name to look up
      Returns:
      The values for the specified header. These are the raw values so if multiple values are specified in a single header that will be returned as a single header value.
      Since:
      Servlet 3.0

    • getHeaderNames

      Collection<String> getHeaderNames()
      Get the header names set for this HTTP response.
      Returns:
      The header names set for this HTTP response.
      Since:
      Servlet 3.0

    • setTrailerFields

      default void setTrailerFields(Supplier<Map<String,String>> supplier)
      Configure the supplier of the trailer headers. The supplier will be called in the scope of the thread that completes the response.
      Trailers that don't meet the requirements of RFC 7230, section 4.1.2 will be ignored.
      The default implementation is a NO-OP.
      Parameters:
      supplier - The supplier for the trailer headers
      Throws:
      IllegalStateException - if this method is called when the underlying protocol does not support trailer headers or if using HTTP/1.1 and the response has already been committed
      Since:
      Servlet 4.0

    • getTrailerFields

      default Supplier<Map<String,String>> getTrailerFields()
      Obtain the supplier of the trailer headers.
      The default implementation returns null.
      Returns:
      The supplier for the trailer headers
      Since:
      Servlet 4.0