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HttpSession (Servlet API Documentation)
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javax.servlet.http</FONT>
<BR>
Interface HttpSession</H2>
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<DL>
<DT>public interface <B>HttpSession</B></DL>
<P>
Provides a way to identify a user across more than one page
request or visit to a Web site and to store information about that user.
<p>The servlet container uses this interface to create a session
between an HTTP client and an HTTP server. The session persists
for a specified time period, across more than one connection or
page request from the user. A session usually corresponds to one
user, who may visit a site many times. The server can maintain a
session in many ways such as using cookies or rewriting URLs.
<p>This interface allows servlets to
<ul>
<li>View and manipulate information about a session, such as
the session identifier, creation time, and last accessed time
<li>Bind objects to sessions, allowing user information to persist
across multiple user connections
</ul>
<p>When an application stores an object in or removes an object from a
session, the session checks whether the object implements
<A HREF="../../../javax/servlet/http/HttpSessionBindingListener.html" title="interface in javax.servlet.http"><CODE>HttpSessionBindingListener</CODE></A>. If it does,
the servlet notifies the object that it has been bound to or unbound
from the session. Notifications are sent after the binding methods complete.
For session that are invalidated or expire, notifications are sent after
the session has been invalidated or expired.
<p> When container migrates a session between VMs in a distributed container
setting, all session attributes implementing the <A HREF="../../../javax/servlet/http/HttpSessionActivationListener.html" title="interface in javax.servlet.http"><CODE>HttpSessionActivationListener</CODE></A>
interface are notified.
<p>A servlet should be able to handle cases in which
the client does not choose to join a session, such as when cookies are
intentionally turned off. Until the client joins the session,
<code>isNew</code> returns <code>true</code>. If the client chooses
not to join
the session, <code>getSession</code> will return a different session
on each request, and <code>isNew</code> will always return
<code>true</code>.
<p>Session information is scoped only to the current web application
(<code>ServletContext</code>), so information stored in one context
will not be directly visible in another.
<P>
<P>
<DL>
<DT><B>Version:</B></DT>
<DD>$Version$</DD>
<DT><B>Author:</B></DT>
<DD>Various</DD>
<DT><B>See Also:</B><DD><A HREF="../../../javax/servlet/http/HttpSessionBindingListener.html" title="interface in javax.servlet.http"><CODE>HttpSessionBindingListener</CODE></A>,
<A HREF="../../../javax/servlet/http/HttpSessionContext.html" title="interface in javax.servlet.http"><CODE>HttpSessionContext</CODE></A></DL>
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<B>Method Summary</B></FONT></TD>
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<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE> java.lang.Object</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../javax/servlet/http/HttpSession.html#getAttribute(java.lang.String)">getAttribute</A></B>(java.lang.String name)</CODE>
<BR>
Returns the object bound with the specified name in this session, or
<code>null</code> if no object is bound under the name.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE> java.util.Enumeration</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../javax/servlet/http/HttpSession.html#getAttributeNames()">getAttributeNames</A></B>()</CODE>
<BR>
Returns an <code>Enumeration</code> of <code>String</code> objects
containing the names of all the objects bound to this session.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE> long</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../javax/servlet/http/HttpSession.html#getCreationTime()">getCreationTime</A></B>()</CODE>
<BR>
Returns the time when this session was created, measured
in milliseconds since midnight January 1, 1970 GMT.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE> java.lang.String</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../javax/servlet/http/HttpSession.html#getId()">getId</A></B>()</CODE>
<BR>
Returns a string containing the unique identifier assigned
to this session.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE> long</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../javax/servlet/http/HttpSession.html#getLastAccessedTime()">getLastAccessedTime</A></B>()</CODE>
<BR>
Returns the last time the client sent a request associated with
this session, as the number of milliseconds since midnight
January 1, 1970 GMT, and marked by the time the container received the request.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE> int</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../javax/servlet/http/HttpSession.html#getMaxInactiveInterval()">getMaxInactiveInterval</A></B>()</CODE>
<BR>
Returns the maximum time interval, in seconds, that
the servlet container will keep this session open between
client accesses.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE> <A HREF="../../../javax/servlet/ServletContext.html" title="interface in javax.servlet">ServletContext</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../javax/servlet/http/HttpSession.html#getServletContext()">getServletContext</A></B>()</CODE>
<BR>
Returns the ServletContext to which this session belongs.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE> <A HREF="../../../javax/servlet/http/HttpSessionContext.html" title="interface in javax.servlet.http">HttpSessionContext</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../javax/servlet/http/HttpSession.html#getSessionContext()">getSessionContext</A></B>()</CODE>
<BR>
<B>Deprecated.</B> <I>As of Version 2.1, this method is
deprecated and has no replacement.
It will be removed in a future
version of the Java Servlet API.</I></TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE> java.lang.Object</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../javax/servlet/http/HttpSession.html#getValue(java.lang.String)">getValue</A></B>(java.lang.String name)</CODE>
<BR>
<B>Deprecated.</B> <I>As of Version 2.2, this method is
replaced by <A HREF="../../../javax/servlet/http/HttpSession.html#getAttribute(java.lang.String)"><CODE>getAttribute(java.lang.String)</CODE></A>.</I></TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE> java.lang.String[]</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../javax/servlet/http/HttpSession.html#getValueNames()">getValueNames</A></B>()</CODE>
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