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.     * @returna <code>long</code> specifying     * when this session was created, expressed in  milliseconds since 1/1/1970 GMT     * @exception IllegalStateExceptionif 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.     * @returna string specifying the identifier     *assigned to this session     * @exception IllegalStateExceptionif 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.     * @returna <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 IllegalStateExceptionif 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 intervalAn 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.    * @returnan 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 namea string specifying the name of the object     * @returnthe object with the specified name     * @exception IllegalStateExceptionif 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 namea string specifying the name of the object     * @returnthe object with the specified name     * @exception IllegalStateExceptionif 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.      * @returnan <code>Enumeration</code> of      *<code>String</code> objects specifying the     *names of all the objects bound to     *this session     * @exception IllegalStateExceptionif 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}     * @returnan array of <code>String</code>     *objects specifying the     *names of all the objects bound to     *this session     * @exception IllegalStateExceptionif 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 namethe name to which the object is bound;     *cannot be null     * @param valuethe object to be bound     * @exception IllegalStateExceptionif 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 namethe name to which the object is bound;     *cannot be null     *     * @param valuethe object to be bound; cannot be null     *     * @exception IllegalStateExceptionif 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 namethe name of the object to     *remove from this session     * @exception IllegalStateExceptionif 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 namethe name of the object to     *remove from this session     * @exception IllegalStateExceptionif this method is called on an     *invalidated session     */    public void removeValue(String name);    /**     * Invalidates this session then unbinds any objects bound     * to it.      * @exception IllegalStateExceptionif 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 IllegalStateExceptionif this method is called on an     *already invalidated session     */    //    public boolean isNew();}