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Interface javax.servlet.ServletRequest

public interface ServletRequest

Some of the data provided by the ServletRequest object includes parameter names and values, attributes, and an input stream. Subclasses of ServletRequest can provide additional protocol-specific data. For example, HTTP data is provided by the interface HttpServletRequest, which extends ServletRequest. This framework provides the servlet's only access to this data.

See Also:

HttpServletRequest

getAttribute(String)

Returns the value of the named attribute of the request, or null if the attribute does not exist.

getContentLength()

Returns the size of the request entity data, or -1 if not known.

getContentType()

Returns the Internet Media Type of the request entity data, or null if not known.

getInputStream()

Returns an input stream for reading the request body.

getParameter(String)

Returns a string containing the lone value of the specified parameter, or null if the parameter does not exist.

getParameterNames()

Returns the parameter names for this request as an enumeration of strings, or an empty enumeration if there are no parameters or the input stream is empty.

getParameterValues(String)

Returns the values of the specified parameter for the request as an array of strings, or null if the named parameter does not exist.

getProtocol()

Returns the protocol and version of the request as a string of the form <protocol>/<major version>.<minor version>.

getRealPath(String)

Applies alias rules to the specified virtual path and returns the corresponding real path, or null if the translation can not be performed for any reason.

getRemoteAddr()

Returns the IP address of the agent that sent the request.

getRemoteHost()

Returns the fully qualified host name of the agent that sent the request.

getScheme()

Returns the scheme of the URL used in this request, for example "http", "https", or "ftp".

getServerName()

Returns the host name of the server that received the request.

getServerPort()

Returns the port number on which this request was received.

 public abstract int getContentLength()

Returns the size of the request entity data, or -1 if not known. Same as the CGI variable CONTENT_LENGTH.

 public abstract String getContentType()

Returns the Internet Media Type of the request entity data, or null if not known. Same as the CGI variable CONTENT_TYPE.

 public abstract String getProtocol()

Returns the protocol and version of the request as a string of the form <protocol>/<major version>.<minor version>. Same as the CGI variable SERVER_PROTOCOL.

 public abstract String getScheme()

Returns the scheme of the URL used in this request, for example "http", "https", or "ftp". Different schemes have different rules for constructing URLs, as noted in RFC 1738. The URL used to create a request may be reconstructed using this scheme, the server name and port, and additional information such as URIs.

 public abstract String getServerName()

Returns the host name of the server that received the request. Same as the CGI variable SERVER_NAME.

 public abstract int getServerPort()

Returns the port number on which this request was received. Same as the CGI variable SERVER_PORT.

 public abstract String getRemoteAddr()

Returns the IP address of the agent that sent the request. Same as the CGI variable REMOTE_ADDR.

 public abstract String getRemoteHost()

Returns the fully qualified host name of the agent that sent the request. Same as the CGI variable REMOTE_HOST.

 public abstract String getRealPath(String path)

Applies alias rules to the specified virtual path and returns the corresponding real path, or null if the translation can not be performed for any reason. For example, an HTTP servlet would resolve the path using the virtual docroot, if virtual hosting is enabled, and with the default docroot otherwise. Calling this method with the string "/" as an argument returns the document root.

Parameters:

path - the virtual path to be translated to a real path

 public abstract ServletInputStream getInputStream() throws IOException

Returns an input stream for reading the request body.

 public abstract String getParameter(String name)

Returns a string containing the lone value of the specified parameter, or null if the parameter does not exist. For example, in an HTTP servlet this method would return the value of the specified query string parameter. Servlet writers should use this method only when they are sure that there is only one value for the parameter. If the parameter has (or could have) multiple values, servlet writers should use getParameterValues. If a multiple valued parameter name is passed as an argument, the return value is implementation dependent.

Parameters:

name - the name of the parameter whose value is required.

See Also:

getParameterValues

 public abstract String[] getParameterValues(String name)

Returns the values of the specified parameter for the request as an array of strings, or null if the named parameter does not exist. For example, in an HTTP servlet this method would return the values of the specified query string or posted form as an array of strings.

Parameters:

name - the name of the parameter whose value is required.

See Also:

getParameter

 public abstract Enumeration getParameterNames()

Returns the parameter names for this request as an enumeration of strings, or an empty enumeration if there are no parameters or the input stream is empty. The input stream would be empty if all the data had been read from the stream returned by the method getInputStream.

 public abstract Object getAttribute(String name)

Returns the value of the named attribute of the request, or null if the attribute does not exist. This method allows access to request information not already provided by the other methods in this interface. Attribute names should follow the same convention as package names. The package names java.*, and javax.* are reserved for use by Javasoft, and com.sun.* is reserved for use by Sun Microsystems.

Parameters:

name - the name of the attribute whose value is required

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