Request object java servlet

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 .

Method Summary

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

Returns the length, in bytes, of the request body and made available by the input stream, or -1 if the length is not known.

Returns the preferred Locale that the client will accept content in, based on the Accept-Language header.

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.

Returns an Enumeration of String objects containing the names of the parameters contained in this request.

Returns an array of String objects containing all of the values the given request parameter has, or null if the parameter does not exist.

Returns the name and version of the protocol the request uses in the form protocol/majorVersion.minorVersion, for example, HTTP/1.1.

Returns a RequestDispatcher object that acts as a wrapper for the resource located at the given path.

Method Detail

getAttribute

java.lang.Object getAttribute(java.lang.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 javax.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 java.* and javax.* are reserved for use by the Servlet specification. Names beginning with sun.* , com.sun.* , oracle.* and com.oracle.* ) are reserved for use by Oracle Corporation.

getAttributeNames

java.util.Enumeration 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.

getCharacterEncoding

java.lang.String getCharacterEncoding()

per request
web application default via the deployment descriptor or ServletContext.setRequestCharacterEncoding(String)
container default via container specific configuration

setCharacterEncoding

void setCharacterEncoding(java.lang.String encoding) throws java.io.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().

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.

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.

getContentType

java.lang.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.

getInputStream

ServletInputStream getInputStream() throws java.io.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.

getParameter

java.lang.String getParameter(java.lang.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.

getParameterNames

java.util.Enumeration 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 .

getParameterValues

java.lang.String[] getParameterValues(java.lang.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.

getParameterMap

java.util.Map 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.

getProtocol

java.lang.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 .

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.

getServerName

java.lang.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.

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.

getReader

java.io.BufferedReader getReader() throws java.io.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.

getRemoteAddr

java.lang.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 .

getRemoteHost

java.lang.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 .

setAttribute

void setAttribute(java.lang.String name, java.lang.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 java.* and javax.* are reserved for use by the Servlet specification. Names beginning with sun.* , com.sun.* , oracle.* and com.oracle.* ) are reserved for use by Oracle Corporation.
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.

removeAttribute

void removeAttribute(java.lang.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 java.* and javax.* are reserved for use by the Servlet specification. Names beginning with sun.* , com.sun.* , oracle.* and com.oracle.* ) are reserved for use by Oracle Corporation.

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.

getLocales

java.util.Enumeration 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.

isSecure

getRequestDispatcher

RequestDispatcher getRequestDispatcher(java.lang.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.

getRealPath

@Deprecated java.lang.String getRealPath(java.lang.String path)

getRemotePort

getLocalName

java.lang.String getLocalName()

getLocalAddr

java.lang.String getLocalAddr()

getLocalPort

getServletContext

startAsync

AsyncContext startAsync() throws java.lang.IllegalStateException

startAsync

AsyncContext startAsync(ServletRequest servletRequest, ServletResponse servletResponse) throws java.lang.IllegalStateException

Request object java servlet