Java-HttpSession

//session给用户一种标志，让用户可以在不同页面以及网站中都有一个特殊的标记
public interface HttpSession {
    /**
     * Returns the time when this session was created, measured
     * in milliseconds since midnight January 1, 1970 GMT.
     * @return				a <code>long</code> specifying
     * 	when this session was created, expressed in  milliseconds since 1/1/1970 GMT
     * @exception IllegalStateException	if this method is called on an
     *					invalidated session
     */
	//session创建时间
    public long getCreationTime();
    /**
     * Returns a string containing the unique identifier assigned
     * to this session. The identifier is assigned
     * by the servlet container and is implementation dependent.
     * @return				a string specifying the identifier
     *					assigned to this session
     * @exception IllegalStateException	if this method is called on an
     *					invalidated session
     */
    //session id
    public String getId();
    /**
     * 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.
     * <p>Actions that your application takes, such as getting or setting
     * a value associated with the session, do not affect the access time.
     * @return				a <code>long</code>
     *					representing the last time
     *					the client sent a request associated
     *					with this session, expressed in
     *					milliseconds since 1/1/1970 GMT
     * @exception IllegalStateException	if this method is called on an
     *					invalidated session
     */
    //最近一次客户端发送与这个session相关联的请求的时间
    public long getLastAccessedTime();
    /**
    * Returns the ServletContext to which this session belongs.
    * @return The ServletContext object for the web application
    * @since 2.3
    */
    //session所属于的ServletContext
    public ServletContext getServletContext();
    /**
     * Specifies the time, in seconds, between client requests before the
     * servlet container will invalidate this session.  A negative time
     * indicates the session should never timeout.
     * @param interval		An integer specifying the number of seconds
     */
    //session失效时间
    public void setMaxInactiveInterval(int interval);
   /**
    * Returns the maximum time interval, in seconds, that
    * the servlet container will keep this session open between
    * client accesses. After this interval, the servlet container
    * will invalidate the session.  The maximum time interval can be set
    * with the <code>setMaxInactiveInterval</code> method.
    * A negative time indicates the session should never timeout.
    * @return		an integer specifying the number of
    *			seconds this session remains open
    *			between client requests
    * @see		#setMaxInactiveInterval
    */
    //获得失效时间
    public int getMaxInactiveInterval();
   /**
    * @deprecated 	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.
    */

    public HttpSessionContext getSessionContext();
    /**
     * Returns the object bound with the specified name in this session, or
     * <code>null</code> if no object is bound under the name.
     * @param name		a string specifying the name of the object
     * @return			the object with the specified name
     * @exception IllegalStateException	if this method is called on an
     *					invalidated session
     */
    //session中name的对象
    public Object getAttribute(String name);
    /**
     * @deprecated 	As of Version 2.2, this method is
     * 			replaced by {@link #getAttribute}.
     * @param name		a string specifying the name of the object
     * @return			the object with the specified name
     * @exception IllegalStateException	if this method is called on an
     *					invalidated session
     */

    public Object getValue(String name);
    /**
     * Returns an <code>Enumeration</code> of <code>String</code> objects
     * containing the names of all the objects bound to this session.
     * @return			an <code>Enumeration</code> of
     *				<code>String</code> objects specifying the
     *				names of all the objects bound to
     *				this session
     * @exception IllegalStateException	if this method is called on an
     *					invalidated session
     */
    //获得所有属性的枚举
    public Enumeration getAttributeNames();
    /**
     * @deprecated 	As of Version 2.2, this method is
     * 			replaced by {@link #getAttributeNames}
     * @return				an array of <code>String</code>
     *					objects specifying the
     *					names of all the objects bound to
     *					this session
     * @exception IllegalStateException	if this method is called on an
     *					invalidated session
     */

    public String[] getValueNames();
    /**
     * Binds an object to this session, using the name specified.
     * If an object of the same name is already bound to the session,
     * the object is replaced.
     * <p>After this method executes, and if the new object
     * implements <code>HttpSessionBindingListener</code>,
     * the container calls
     * <code>HttpSessionBindingListener.valueBound</code>. The container then
     * notifies any <code>HttpSessionAttributeListener</code>s in the web
     * application.
     * <p>If an object was already bound to this session of this name
     * that implements <code>HttpSessionBindingListener</code>, its
     * <code>HttpSessionBindingListener.valueUnbound</code> method is called.
     * <p>If the value passed in is null, this has the same effect as calling
     * <code>removeAttribute()<code>.
     * @param name			the name to which the object is bound;
     *					cannot be null
     * @param value			the object to be bound
     * @exception IllegalStateException	if this method is called on an
     *					invalidated session
     */
    //设置属性
    public void setAttribute(String name, Object value);
    /**
     *
     * @deprecated 	As of Version 2.2, this method is
     * 			replaced by {@link #setAttribute}
     *
     * @param name			the name to which the object is bound;
     *					cannot be null
     *
     * @param value			the object to be bound; cannot be null
     *
     * @exception IllegalStateException	if this method is called on an
     *					invalidated session
     *
     */
    public void putValue(String name, Object value);
    /**
     * Removes the object bound with the specified name from
     * this session. If the session does not have an object
     * bound with the specified name, this method does nothing.
     * <p>After this method executes, and if the object
     * implements <code>HttpSessionBindingListener</code>,
     * the container calls
     * <code>HttpSessionBindingListener.valueUnbound</code>. The container
     * then notifies any <code>HttpSessionAttributeListener</code>s in the web
     * application.
     * @param name				the name of the object to
     *						remove from this session
     * @exception IllegalStateException	if this method is called on an
     *					invalidated session
     */
    //删除属性
    public void removeAttribute(String name);
    /**
     * @deprecated 	As of Version 2.2, this method is
     * 			replaced by {@link #removeAttribute}
     * @param name				the name of the object to
     *						remove from this session
     * @exception IllegalStateException	if this method is called on an
     *					invalidated session
     */
    public void removeValue(String name);
    /**
     * Invalidates this session then unbinds any objects bound
     * to it.
     * @exception IllegalStateException	if this method is called on an
     *					already invalidated session
     */
    //session无效
    public void invalidate();
    /**
     * Returns <code>true</code> if the client does not yet know about the
     * session or if the client chooses not to join the session.  For
     * example, if the server used only cookie-based sessions, and
     * the client had disabled the use of cookies, then a session would
     * be new on each request.
     * @return 				<code>true</code> if the
     *					server has created a session,
     *					but the client has not yet joined
     * @exception IllegalStateException	if this method is called on an
     *					already invalidated session
     */
    //
    public boolean isNew();
}