Session

这次只举例子，从例子中学习。直接上代码，建议不要粘贴复制，用手完全照着敲出来，增强印象。（没有用到数据库）

1. 4.12.php开启会话 session_start() ;

<?php
/*
 * 
 * @Authors peng--jun 
 * @Email   1098325951@qq.com
 * @Date    2015-11-04 13:00:16
 * @Link    http://www.cnblogs.com/xs-yqz/
 * @version $Id$
 ==========================================
 */

session_start();
header("Content-type: text/html; charset=UTF-8"); 
$_SESSION["username"]="彭军";
$_SESSION["username"]="彭军军";//修改Session变量值
$_SESSION["age"] = 21;
$email = "1098325951@qq.com";
$_SESSION["email"] = $email;//将变量信息存储到Session中
$_SESSION["user"]  = array('name' =>"peng-jun" ,'pwd' => "123" ); //将数组存入Session 中
?>

2.  4.13.php将session里面的值显示出来

 header("Content-type: text/html; charset=UTF-8"); 
 session_start();
 echo $_SESSION["username"];
 echo $_SESSION["age"];
 echo $_SESSION["email"];
 echo $_SESSION["user"];

3. 以下4.14.php通过一个表单的例子（admin ,123）来验证会话

<?php
/*
 * 
 * @Authors peng--jun 
 * @Email   1098325951@qq.com
 * @Date    2015-11-04 13:16:06
 * @Link    http://www.cnblogs.com/xs-yqz/
 * @version $Id$
 ==========================================
 */
 header("Content-type: text/html; charset=UTF-8"); 
 session_start();
 if (isset($_POST["submit"])) {
     $user = $_POST["username"];
     $pw = $_POST["pwd"];
     if ($user == "admin" && $pw == "123") {
         $_SESSION["user"] = $user;//通过这样来传递session参数
         header('Location:4.15.php');//header的location进行页面的跳转
     }else{
         echo "用户名或密码错误";
     }
 }else{
     echo '
       <form method ="post" action="">
       用户名：<input type="text" name="username" />
       密  码：<input type ="password" name="pwd"/>
       <input name="submit" type="submit" value="登录"/>
       </form>
     ';
 }
?>

4 4.15.php验证通过的页面

 header("Content-type: text/html; charset=UTF-8"); 
 session_start();
 if (isset($_SESSION['user'])) {
     echo "欢迎你，".$_SESSION['user']."<br/>
          <a href = '4.16.php?action=logout'>注销登录</a>";
 }else{
     echo "未登录用户禁止访问";
 }

5 用户注销的页面代码4.16.php

if ($_GET["action"] == "logout") {
     session_start();//启动会话
     setcookie("user","",time()-60);//将会话Cookie变量user设置为过期，即删除Cookie
     session_unset();//删除$_SESSION中的Session变量
     session_destroy();//销毁Session，删除Session ID
     header("location:4.14.php");  //回到登陆页面
 }