Java The Complete Reference, Seventh Edition

The ServletRequest Interface

TheServletRequestinterface enables a servlet toobtain information about a client request.
Several of its methods are summarized in Table 31-3.

The ServletResponse Interface

TheServletResponseinterface enables a servlet to formulate a response for a client. Several
of its methods are summarized in Table 31-4.

Chapter 31: Servlets 913

Method Description

Object getAttribute(Stringattr) Returns the value of the ser ver attribute namedattr.

String getMimeType(Stringfile) Returns the MIME type offile.

String getRealPath(Stringvpath) Returns the real path that corresponds to the virtual

pathvpath.

String getSer verInfo( ) Returns information about the ser ver.

void log(Strings) Writessto the ser vlet log.

void log(Strings, Throwablee) Writessand the stack trace foreto the ser vlet log.

void setAttribute(Stringattr, Objectval) Sets the attribute specified byattrto the value

passed inval.

TABLE 31-2 Various Methods Defined byServletContext

Method Description

void destroy( ) Called when the ser vlet is unloaded.

Ser vletConfig getSer vletConfig( ) Returns aServletConfigobject that contains any initialization

parameters.

String getSer vletInfo( ) Returns a string describing the ser vlet.

void init(Ser vletConfigsc)

throws Ser vletException

Called when the ser vlet is initialized. Initialization

parameters for the ser vlet can be obtained fromsc.

AnUnavailableExceptionshould be thrown if the

ser vlet cannot be initialized.

void ser vice(Ser vletRequestreq,

Ser vletResponseres)

throws Ser vletException,

IOException

Called to process a request from a client. The request from

the client can be read fromreq.The response to the client

can be written tores.An exception is generated if a ser vlet

or IO problem occurs.

TABLE 31-1 The Methods Defined byServlet