Interface ServletRequest

All Known Subinterfaces:
HttpServletRequest
All Known Implementing Classes:
HttpServletRequestWrapper, ServletRequestWrapper
public interface ServletRequest
Defines an object to provide client request information to a servlet. The servlet container creates a ServletRequest object and passes it as an argument to the servlet's service method.

A ServletRequest object provides data including parameter name and values, attributes, and an input stream. Interfaces that extend ServletRequest can provide additional protocol-specific data (for example, HTTP data is provided by HttpServletRequest.

See Also:

  • Method Details

    • getAttribute

      Object getAttribute(String name)
      Returns the value of the named attribute as an Object, or null if no attribute of the given name exists.

      Attributes can be set two ways. The servlet container may set attributes to make available custom information about a request. For example, for requests made using HTTPS, the attribute jakarta.servlet.request.X509Certificate can be used to retrieve information on the certificate of the client. Attributes can also be set programmatically using setAttribute(java.lang.String, java.lang.Object). This allows information to be embedded into a request before a RequestDispatcher call.

      Attribute names should follow the same conventions as package names. Names beginning with jakarta.* are reserved for use by the Jakarta EE platform.

      Parameters:
      name - a String specifying the name of the attribute
      Returns:
      an Object containing the value of the attribute, or null if the attribute does not exist

    • getAttributeNames

      Enumeration<String> getAttributeNames()
      Returns an Enumeration containing the names of the attributes available to this request. This method returns an empty Enumeration if the request has no attributes available to it.
      Returns:
      an Enumeration of strings containing the names of the request's attributes

    • getCharacterEncoding

      String getCharacterEncoding()
      Returns the name of the character encoding used in the body of this request. This method returns null if the no character encoding has been specified. The following priority order is used to determine the specified encoding:
      1. per request
      2. web application default via the deployment descriptor or ServletContext.setRequestCharacterEncoding(String)
      3. container default via container specific configuration
      Returns:
      a String containing the name of the character encoding, or null if the request does not specify a character encoding

    • setCharacterEncoding

      void setCharacterEncoding(String encoding) throws UnsupportedEncodingException
      Overrides the name of the character encoding used in the body of this request. This method must be called prior to reading request parameters or reading input using getReader().
      Parameters:
      encoding - a String containing the name of the character encoding
      Throws:
      UnsupportedEncodingException - if this is not a valid encoding

    • setCharacterEncoding

      default void setCharacterEncoding(Charset encoding)
      Overrides the character encoding used in the body of this request. This method must be called prior to reading request parameters or reading input using getReader(). Otherwise, it has no effect.

      Implementations are strongly encouraged to override this default method and provide a more efficient implementation.

      Parameters:
      encoding - Charset representing the character encoding.
      Since:
      Servlet 6.1

    • getContentLength

      int getContentLength()
      Returns the length, in bytes, of the request body and made available by the input stream, or -1 if the length is not known. For HTTP servlets, same as the value of the CGI variable CONTENT_LENGTH.
      Returns:
      an integer containing the length of the request body or -1 if the length is not known or is greater than Integer.MAX_VALUE

    • getContentLengthLong

      long getContentLengthLong()
      Returns the length, in bytes, of the request body and made available by the input stream, or -1 if the length is not known. For HTTP servlets, same as the value of the CGI variable CONTENT_LENGTH.
      Returns:
      a long integer containing the length of the request body or -1 if the length is not known
      Since:
      Servlet 3.1

    • getContentType

      String getContentType()
      Returns the MIME type of the body of the request, or null if the type is not known. For HTTP servlets, same as the value of the CGI variable CONTENT_TYPE.
      Returns:
      a String containing the name of the MIME type of the request, or null if the type is not known

    • getInputStream

      ServletInputStream getInputStream() throws IOException
      Retrieves the body of the request as binary data using a ServletInputStream. Either this method or getReader() may be called to read the body, not both.
      Returns:
      a ServletInputStream object containing the body of the request
      Throws:
      IllegalStateException - if the getReader() method has already been called for this request
      IOException - if an input or output exception occurred

    • getParameter

      String getParameter(String name)
      Returns the value of a request parameter as a String, or null if the parameter does not exist. Request parameters are extra information sent with the request. For HTTP servlets, parameters are contained in the query string or posted form data.

      You should only use this method when you are sure the parameter has only one value. If the parameter might have more than one value, use getParameterValues(java.lang.String).

      If you use this method with a multivalued parameter, the value returned is equal to the first value in the array returned by getParameterValues.

      If the parameter data was sent in the request body, such as occurs with an HTTP POST request, then reading the body directly via getInputStream() or getReader() can interfere with the execution of this method.

      If not already parsed, calling this method will trigger the parsing of the query string, POSTed form data where the request body has content type is application/x-www-form-urlencoded and POSTed form data where the request body has content-type multipart/form-data and the Servlet is configured with a MultipartConfig annotation or a multipart-config element in the deployment descriptor.

      Parameters:
      name - a String specifying the name of the parameter
      Returns:
      a String representing the single value of the parameter
      Throws:
      IllegalStateException - if parameter parsing is triggered and a problem is encountered parsing the parameters including, but not limited to: invalid percent (%nn) encoding; invalid byte sequence for the specified character set; I/O errors reading the request body; and triggering a container defined limit related to parameter parsing. Containers may provide container specific options to handle some or all of these errors in an alternative manner that may include not throwing an exception.
      See Also:

    • getParameterNames

      Enumeration<String> getParameterNames()
      Returns an Enumeration of String objects containing the names of the parameters contained in this request. If the request has no parameters, the method returns an empty Enumeration.

      If not already parsed, calling this method will trigger the parsing of the query string, POSTed form data where the request body has content type is application/x-www-form-urlencoded and POSTed form data where the request body has content-type multipart/form-data and the Servlet is configured with a MultipartConfig annotation or a multipart-config element in the deployment descriptor.

      Returns:
      an Enumeration of String objects, each String containing the name of a request parameter; or an empty Enumeration if the request has no parameters
      Throws:
      IllegalStateException - if parameter parsing is triggered and a problem is encountered parsing the parameters including, but not limited to: invalid percent (%nn) encoding; invalid byte sequence for the specified character set; I/O errors reading the request body; and triggering a container defined limit related to parameter parsing. Containers may provide container specific options to handle some or all of these errors in an alternative manner that may include not throwing an exception.

    • getParameterValues

      String[] getParameterValues(String name)
      Returns an array of String objects containing all of the values the given request parameter has, or null if the parameter does not exist.

      If the parameter has a single value, the array has a length of 1.

      If not already parsed, calling this method will trigger the parsing of the query string, POSTed form data where the request body has content type is application/x-www-form-urlencoded and POSTed form data where the request body has content-type multipart/form-data and the Servlet is configured with a MultipartConfig annotation or a multipart-config element in the deployment descriptor.

      Parameters:
      name - a String containing the name of the parameter whose value is requested
      Returns:
      an array of String objects containing the parameter's values
      Throws:
      IllegalStateException - if parameter parsing is triggered and a problem is encountered parsing the parameters including, but not limited to: invalid percent (%nn) encoding; invalid byte sequence for the specified character set; I/O errors reading the request body; and triggering a container defined limit related to parameter parsing. Containers may provide container specific options to handle some or all of these errors in an alternative manner that may include not throwing an exception.
      See Also:

    • getParameterMap

      Map<String,String[]> getParameterMap()
      Returns a java.util.Map of the parameters of this request. Request parameters are extra information sent with the request. For HTTP servlets, parameters are contained in the query string or posted form data.

      If not already parsed, calling this method will trigger the parsing of the query string, POSTed form data where the request body has content type is application/x-www-form-urlencoded and POSTed form data where the request body has content-type multipart/form-data and the Servlet is configured with a MultipartConfig annotation or a multipart-config element in the deployment descriptor.

      Returns:
      an immutable java.util.Map containing parameter names as keys and parameter values as map values. The keys in the parameter map are of type String. The values in the parameter map are of type String array.
      Throws:
      IllegalStateException - if parameter parsing is triggered and a problem is encountered parsing the parameters including, but not limited to: invalid percent (%nn) encoding; invalid byte sequence for the specified character set; I/O errors reading the request body; and triggering a container defined limit related to parameter parsing. Containers may provide container specific options to handle some or all of these errors in an alternative manner that may include not throwing an exception.

    • getProtocol

      String getProtocol()
      Returns the name and version of the protocol the request uses in the form protocol/majorVersion.minorVersion, for example, HTTP/1.1. For HTTP servlets, the value returned is the same as the value of the CGI variable SERVER_PROTOCOL.
      Returns:
      a String containing the protocol name and version number

    • getScheme

      String getScheme()
      Returns the name of the scheme used to make this request, for example, http, https, or ftp. Different schemes have different rules for constructing URLs, as noted in RFC 1738.
      Returns:
      a String containing the name of the scheme used to make this request

    • getServerName

      String getServerName()
      Returns the host name of the server to which the request was sent. It is the value of the part before ":" in the Host header value, if any, or the resolved server name, or the server IP address.
      Returns:
      a String containing the name of the server

    • getServerPort

      int getServerPort()
      Returns the port number to which the request was sent. It is the value of the part after ":" in the Host header value, if any, or the server port where the client connection was accepted on.
      Returns:
      an integer specifying the port number

    • getReader

      BufferedReader getReader() throws IOException
      Retrieves the body of the request as character data using a BufferedReader. The reader translates the character data according to the character encoding used on the body. Either this method or getInputStream() may be called to read the body, not both.
      Returns:
      a BufferedReader containing the body of the request
      Throws:
      UnsupportedEncodingException - if the character set encoding used is not supported and the text cannot be decoded
      IllegalStateException - if getInputStream() method has been called on this request
      IOException - if an input or output exception occurred
      See Also:

    • getRemoteAddr

      String getRemoteAddr()
      Returns the Internet Protocol (IP) address of the client or last proxy that sent the request. For HTTP servlets, same as the value of the CGI variable REMOTE_ADDR.
      Returns:
      a String containing the IP address of the client that sent the request

    • getRemoteHost

      String getRemoteHost()
      Returns the fully qualified name of the client or the last proxy that sent the request. If the engine cannot or chooses not to resolve the hostname (to improve performance), this method returns the dotted-string form of the IP address. For HTTP servlets, same as the value of the CGI variable REMOTE_HOST.
      Returns:
      a String containing the fully qualified name of the client

    • setAttribute

      void setAttribute(String name, Object o)
      Stores an attribute in this request. Attributes are reset between requests. This method is most often used in conjunction with RequestDispatcher.

      Attribute names should follow the same conventions as package names. Names beginning with jakarta.* are reserved for use by the Jakarta EE platform.

      If the object passed in is null, the effect is the same as calling removeAttribute(java.lang.String).
      It is warned that when the request is dispatched from the servlet resides in a different web application by RequestDispatcher, the object set by this method may not be correctly retrieved in the caller servlet.

      Parameters:
      name - a String specifying the name of the attribute
      o - the Object to be stored

    • removeAttribute

      void removeAttribute(String name)
      Removes an attribute from this request. This method is not generally needed as attributes only persist as long as the request is being handled.

      Attribute names should follow the same conventions as package names. Names beginning with jakarta.* are reserved for use by the Jakarta EE platform.

      Parameters:
      name - a String specifying the name of the attribute to remove

    • getLocale

      Locale getLocale()
      Returns the preferred Locale that the client will accept content in, based on the Accept-Language header. If the client request doesn't provide an Accept-Language header, this method returns the default locale for the server.
      Returns:
      the preferred Locale for the client

    • getLocales

      Enumeration<Locale> getLocales()
      Returns an Enumeration of Locale objects indicating, in decreasing order starting with the preferred locale, the locales that are acceptable to the client based on the Accept-Language header. If the client request doesn't provide an Accept-Language header, this method returns an Enumeration containing one Locale, the default locale for the server.
      Returns:
      an Enumeration of preferred Locale objects for the client

    • isSecure

      boolean isSecure()
      Returns a boolean indicating whether this request was made using a secure channel, such as HTTPS.
      Returns:
      a boolean indicating if the request was made using a secure channel

    • getRequestDispatcher

      RequestDispatcher getRequestDispatcher(String path)
      Returns a RequestDispatcher object that acts as a wrapper for the resource located at the given path. A RequestDispatcher object can be used to forward a request to the resource or to include the resource in a response. The resource can be dynamic or static.

      The pathname specified may be relative, although it cannot extend outside the current servlet context. If the path begins with a "/" it is interpreted as relative to the current context root. This method returns null if the servlet container cannot return a RequestDispatcher.

      The difference between this method and ServletContext.getRequestDispatcher(java.lang.String) is that this method can take a relative path.

      Parameters:
      path - a String specifying the pathname to the resource. If it is relative, it must be relative against the current servlet.
      Returns:
      a RequestDispatcher object that acts as a wrapper for the resource at the specified path, or null if the servlet container cannot return a RequestDispatcher
      See Also:

    • getRemotePort

      int getRemotePort()
      Returns the Internet Protocol (IP) source port of the client or last proxy that sent the request.
      Returns:
      an integer specifying the port number
      Since:
      Servlet 2.4

    • getLocalName

      String getLocalName()
      Returns the host name of the Internet Protocol (IP) interface on which the request was received.
      Returns:
      a String containing the host name of the IP on which the request was received.
      Since:
      Servlet 2.4

    • getLocalAddr

      String getLocalAddr()
      Returns the Internet Protocol (IP) address of the interface on which the request was received.
      Returns:
      a String containing the IP address on which the request was received.
      Since:
      Servlet 2.4

    • getLocalPort

      int getLocalPort()
      Returns the Internet Protocol (IP) port number of the interface on which the request was received.
      Returns:
      an integer specifying the port number
      Since:
      Servlet 2.4

    • getServletContext

      ServletContext getServletContext()
      Returns:
      TODO
      Since:
      Servlet 3.0 TODO SERVLET3 - Add comments

    • startAsync

      AsyncContext startAsync() throws IllegalStateException
      Returns:
      TODO
      Throws:
      IllegalStateException - If async is not supported for this request
      Since:
      Servlet 3.0 TODO SERVLET3 - Add comments

    • startAsync

      AsyncContext startAsync(ServletRequest servletRequest, ServletResponse servletResponse) throws IllegalStateException
      Parameters:
      servletRequest - The ServletRequest with which to initialise the asynchronous context
      servletResponse - The ServletResponse with which to initialise the asynchronous context
      Returns:
      TODO
      Throws:
      IllegalStateException - If async is not supported for this request
      Since:
      Servlet 3.0 TODO SERVLET3 - Add comments

    • isAsyncStarted

      boolean isAsyncStarted()
      Returns:
      TODO
      Since:
      Servlet 3.0 TODO SERVLET3 - Add comments

    • isAsyncSupported

      boolean isAsyncSupported()
      Returns:
      TODO
      Since:
      Servlet 3.0 TODO SERVLET3 - Add comments

    • getAsyncContext

      AsyncContext getAsyncContext()
      Get the current AsyncContext.
      Returns:
      The current AsyncContext
      Throws:
      IllegalStateException - if the request is not in asynchronous mode (i.e. @link #isAsyncStarted() is false)
      Since:
      Servlet 3.0

    • getDispatcherType

      DispatcherType getDispatcherType()
      Returns:
      TODO
      Since:
      Servlet 3.0 TODO SERVLET3 - Add comments

    • getRequestId

      String getRequestId()
      Obtain a unique (within the lifetime of the Servlet container) identifier string for this request.

      There is no defined format for this string. The format is implementation dependent.

      Returns:
      A unique identifier for the request
      Since:
      Servlet 6.0

    • getProtocolRequestId

      String getProtocolRequestId()
      Obtain the request identifier for this request as defined by the protocol in use. Note that some protocols do not define such an identifier.

      Examples of protocol provided request identifiers include:

      HTTP 1.x
      None, so the empty string should be returned
      HTTP 2
      The stream identifier
      HTTP 3
      The stream identifier
      AJP
      None, so the empty string should be returned
      Returns:
      The request identifier if one is defined, otherwise an empty string
      Since:
      Servlet 6.0

    • getServletConnection

      ServletConnection getServletConnection()
      Obtain details of the network connection to the Servlet container that is being used by this request. The information presented may differ from information presented elsewhere in the Servlet API as raw information is presented without adjustments for, example, use of reverse proxies that may be applied elsewhere in the Servlet API.
      Returns:
      The network connection details.
      Since:
      Servlet 6.0