Interface: javax.servlet.ServletRequest
- public interface ServletRequest
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 javax.servlet.http.HttpServletRequest.
Methods
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getAttributetop
Returns the value of the named attribute as anObject, ornullif 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.X509Certificatecan be used to retrieve information on the certificate of the client. Attributes can also be set programatically using javax.servlet.ServletRequest.setAttribute(java.lang.String, java.lang.Object). This allows information to be embedded into a request before a javax.servlet.RequestDispatcher call.Attribute names should follow the same conventions as package names. This specification reserves names matching
java.*,javax.*, andsun.*. -
getAttributeNamestop
public Enumeration getAttributeNames()Returns anEnumerationcontaining the names of the attributes available to this request. This method returns an emptyEnumerationif the request has no attributes available to it. -
getCharacterEncodingtop
public String getCharacterEncoding()Returns the name of the character encoding used in the body of this request. This method returnsnullif the request does not specify a character encoding -
getContentLengthtop
public 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. -
getContentTypetop
public String getContentType()Returns the MIME type of the body of the request, ornullif the type is not known. For HTTP servlets, same as the value of the CGI variable CONTENT_TYPE. -
getInputStreamtop
public ServletInputStream getInputStream() throws IOExceptionRetrieves the body of the request as binary data using a javax.servlet.ServletInputStream. Either this method or javax.servlet.ServletRequest.getReader() may be called to read the body, not both. -
getLocalAddrtop
public String getLocalAddr()Returns the Internet Protocol (IP) address of the interface on which the request was received. -
getLocalNametop
public String getLocalName()Returns the host name of the Internet Protocol (IP) interface on which the request was received. -
getLocalPorttop
public int getLocalPort()Returns the Internet Protocol (IP) port number of the interface on which the request was received. -
getLocaletop
public Locale getLocale()Returns the preferredLocalethat 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. -
getLocalestop
public Enumeration getLocales()Returns anEnumerationofLocaleobjects 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 anEnumerationcontaining oneLocale, the default locale for the server. -
getParametertop
Returns the value of a request parameter as aString, ornullif 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 javax.servlet.ServletRequest.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 javax.servlet.ServletRequest.getInputStream() or javax.servlet.ServletRequest.getReader() can interfere with the execution of this method.
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getParameterMaptop
public 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. -
getParameterNamestop
public Enumeration getParameterNames()Returns anEnumerationofStringobjects containing the names of the parameters contained in this request. If the request has no parameters, the method returns an emptyEnumeration. -
getParameterValuestop
Returns an array ofStringobjects containing all of the values the given request parameter has, ornullif the parameter does not exist.If the parameter has a single value, the array has a length of 1.
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getProtocoltop
public 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 variableSERVER_PROTOCOL. -
getReadertop
public BufferedReader getReader() throws IOExceptionRetrieves the body of the request as character data using aBufferedReader. The reader translates the character data according to the character encoding used on the body. Either this method or javax.servlet.ServletRequest.getInputStream() may be called to read the body, not both. -
getRealPathtop
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getRemoteAddrtop
public 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 variableREMOTE_ADDR. -
getRemoteHosttop
public 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 variableREMOTE_HOST. -
getRemotePorttop
public int getRemotePort()Returns the Internet Protocol (IP) source port of the client or last proxy that sent the request. -
getRequestDispatchertop
public RequestDispatcher getRequestDispatcher(String path)Returns a javax.servlet.RequestDispatcher object that acts as a wrapper for the resource located at the given path. ARequestDispatcherobject 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
nullif the servlet container cannot return aRequestDispatcher.The difference between this method and javax.servlet.ServletContext.getRequestDispatcher(java.lang.String) is that this method can take a relative path.
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getSchemetop
public String getScheme()Returns the name of the scheme used to make this request, for example,http,https, orftp. Different schemes have different rules for constructing URLs, as noted in RFC 1738. -
getServerNametop
public String getServerName()Returns the host name of the server to which the request was sent. It is the value of the part before ":" in theHostheader value, if any, or the resolved server name, or the server IP address. -
getServerPorttop
public int getServerPort()Returns the port number to which the request was sent. It is the value of the part after ":" in theHostheader value, if any, or the server port where the client connection was accepted on. -
isSecuretop
public boolean isSecure()Returns a boolean indicating whether this request was made using a secure channel, such as HTTPS. -
removeAttributetop
public 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
java.*,javax.*, andcom.sun.*, are reserved for use by Sun Microsystems. -
setAttributetop
Stores an attribute in this request. Attributes are reset between requests. This method is most often used in conjunction with javax.servlet.RequestDispatcher.Attribute names should follow the same conventions as package names. Names beginning with
java.*,javax.*, andcom.sun.*, are reserved for use by Sun Microsystems.
If the object passed in is null, the effect is the same as calling javax.servlet.ServletRequest.removeAttribute(java.lang.String).
It is warned that when the request is dispatched from the servlet resides in a different web application byRequestDispatcher, the object set by this method may not be correctly retrieved in the caller servlet. -
setCharacterEncodingtop
public void setCharacterEncoding(String env) throws UnsupportedEncodingExceptionOverrides 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(). Otherwise, it has no effect.
