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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><!--NewPage--><HTML><HEAD><!-- Generated by javadoc (build 1.4.2_02) on Thu Nov 13 17:20:50 PST 2003 --><TITLE>HttpSession (Java 2 Platform Ent. Ed. v1.4)</TITLE><META NAME="keywords" CONTENT="javax.servlet.http.HttpSession interface"><LINK REL ="stylesheet" TYPE="text/css" HREF="../../../stylesheet.css" TITLE="Style"><SCRIPT type="text/javascript">function windowTitle(){ parent.document.title="HttpSession (Java 2 Platform Ent. Ed. v1.4)";}</SCRIPT></HEAD><BODY BGCOLOR="white" onload="windowTitle();"><!-- ========= START OF TOP NAVBAR ======= --><A NAME="navbar_top"><!-- --></A><A HREF="#skip-navbar_top" title="Skip navigation links"></A><TABLE BORDER="0" WIDTH="100%" CELLPADDING="1" CELLSPACING="0" SUMMARY=""><TR><TD COLSPAN=3 BGCOLOR="#EEEEFF" CLASS="NavBarCell1"><A NAME="navbar_top_firstrow"><!-- --></A><TABLE BORDER="0" CELLPADDING="0" CELLSPACING="3" SUMMARY=""> <TR ALIGN="center" VALIGN="top"> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../overview-summary.html"><FONT CLASS="NavBarFont1"><B>Overview</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="package-summary.html"><FONT CLASS="NavBarFont1"><B>Package</B></FONT></A> </TD> <TD BGCOLOR="#FFFFFF" CLASS="NavBarCell1Rev"> <FONT CLASS="NavBarFont1Rev"><B>Class</B></FONT> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="package-tree.html"><FONT CLASS="NavBarFont1"><B>Tree</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../deprecated-list.html"><FONT CLASS="NavBarFont1"><B>Deprecated</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../index-all.html"><FONT CLASS="NavBarFont1"><B>Index</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../help-doc.html"><FONT CLASS="NavBarFont1"><B>Help</B></FONT></A> </TD> </TR></TABLE></TD><TD ALIGN="right" VALIGN="top" ROWSPAN=3><EM><b>Java<sup><font size=-2>TM</font></sup> 2 Platform<br>Ent. Ed. v1.4</b></EM></TD></TR><TR><TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../../javax/servlet/http/HttpServletResponse.html" title="interface in javax.servlet.http"><B>PREV CLASS</B></A> <A HREF="../../../javax/servlet/http/HttpSessionActivationListener.html" title="interface in javax.servlet.http"><B>NEXT CLASS</B></A></FONT></TD><TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../../index.html" target="_top"><B>FRAMES</B></A> <A HREF="HttpSession.html" target="_top"><B>NO FRAMES</B></A> <SCRIPT type="text/javascript"> <!-- if(window==top) { document.writeln('<A HREF="../../../allclasses-noframe.html"><B>All Classes</B></A>'); } //--></SCRIPT><NOSCRIPT> <A HREF="../../../allclasses-noframe.html"><B>All Classes</B></A></NOSCRIPT></FONT></TD></TR><TR><TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2"> SUMMARY: NESTED | FIELD | CONSTR | <A HREF="#method_summary">METHOD</A></FONT></TD><TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2">DETAIL: FIELD | CONSTR | <A HREF="#method_detail">METHOD</A></FONT></TD></TR></TABLE><A NAME="skip-navbar_top"></A><!-- ========= END OF TOP NAVBAR ========= --><HR><!-- ======== START OF CLASS DATA ======== --><H2><FONT SIZE="-1">javax.servlet.http</FONT><BR>Interface HttpSession</H2><HR><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 invalidatd 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><HR><P><!-- ======== NESTED CLASS SUMMARY ======== --><!-- =========== FIELD SUMMARY =========== --><!-- ======== CONSTRUCTOR SUMMARY ======== --><!-- ========== METHOD SUMMARY =========== --><A NAME="method_summary"><!-- --></A><TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""><TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"><TD COLSPAN=2><FONT SIZE="+2"><B>Method Summary</B></FONT></TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> <A HREF="http://java.sun.com/j2se/1.4/docs/api/java/lang/Object.html" title="class or interface in java.lang">Object</A></CODE></FONT></TD><TD><CODE><B><A HREF="../../../javax/servlet/http/HttpSession.html#getAttribute(java.lang.String)">getAttribute</A></B>(<A HREF="http://java.sun.com/j2se/1.4/docs/api/java/lang/String.html" title="class or interface in java.lang">String</A> 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> <A HREF="http://java.sun.com/j2se/1.4/docs/api/java/util/Enumeration.html" title="class or interface in java.util">Enumeration</A></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> <A HREF="http://java.sun.com/j2se/1.4/docs/api/java/lang/String.html" title="class or interface in java.lang">String</A></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> <A HREF="http://java.sun.com/j2se/1.4/docs/api/java/lang/Object.html" title="class or interface in java.lang">Object</A></CODE></FONT></TD><TD><CODE><B><A HREF="../../../javax/servlet/http/HttpSession.html#getValue(java.lang.String)">getValue</A></B>(<A HREF="http://java.sun.com/j2se/1.4/docs/api/java/lang/String.html" title="class or interface in java.lang">String</A> 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> <A HREF="http://java.sun.com/j2se/1.4/docs/api/java/lang/String.html" title="class or interface in java.lang">String</A>[]</CODE></FONT></TD>⌨️ 快捷键说明
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