Java The Complete Reference, Seventh Edition

The HttpServlet Class

TheHttpServletclass extendsGenericServlet. It is commonly used when developing servlets
that receive and process HTTP requests. The methods of theHttpServletclass are summarized
in Table 31-9.

The HttpSessionEvent Class

HttpSessionEventencapsulates session events. It extendsEventObjectand is generated when
a change occurs to the session. It defines this constructor:

HttpSessionEvent(HttpSessionsession)

Here,sessionis the source of the event.
HttpSessionEventdefines one method,getSession( ), which is shown here:

HttpSession getSession( )

It returns the session in which the event occurred.

Chapter 31: Servlets 921

Method Description

void doDelete(HttpSer vletRequestreq,

HttpSer vletResponseres)

throws IOException, Ser vletException

Handles an HTTP DELETE request.

void doGet(HttpSer vletRequestreq,

HttpSer vletResponseres)

throws IOException, Ser vletException

Handles an HTTP GET request.

void doHead(HttpSer vletRequestreq,

HttpSer vletResponseres)

throws IOException,

Ser vletException

Handles an HTTP HEAD request.

void doOptions(HttpSer vletRequestreq,

HttpSer vletResponseres)

throws IOException, Ser vletException

Handles an HTTP OPTIONS request.

void doPost(HttpSer vletRequestreq,

HttpSer vletResponseres)

throws IOException, Ser vletException

Handles an HTTP POST request.

void doPut(HttpSer vletRequestreq,

HttpSer vletResponseres)

throws IOException, Ser vletException

Handles an HTTP PUT request.

void doTrace(HttpSer vletRequestreq,

HttpSer vletResponseres)

throws IOException, Ser vletException

Handles an HTTP TRACE request.

long

getLastModified(HttpSer vletRequestreq)

Returns the time (in milliseconds since midnight, Januar y 1,

1970, GMT) when the requested resource was last modified.

void ser vice(HttpSer vletRequestreq,

HttpSer vletResponseres)

throws IOException, Ser vletException

Called by the ser ver when an HTTP request arrives for this

ser vlet. The arguments provide access to the HTTP request and

response, respectively.

TABLE 31-9 The Methods Defined byHttpServlet