1、php默认是不开启会话的，要使用会话用两种方法：（1）使用session_start();显示的开启会话。（2）在php.ini中找到如下的一行：找到session.auto_start = 0，将0设置为1.下面通过一个模拟购物车的程序来展示seeion的基本操作。
session1.php
1 <?php 2 //session_start(); 3 ?> 4 <!DOCTYPE html> 5 <html> 6 <head> 7 <title>Storing an array with a session</title> 8 </head> 9 <body> 10 <h1>Product Choice Page</h1> 11 <?php 12 if(isset($_POST['form_products'])){ 13 if(!empty($_SESSION['products'])){ 14 $products = array_unique( 15 array_merge(unserialize($_SESSION['products']), $_POST['form_products'])); 16 $_SESSION['products']=serialize($products); 17 } 18 else{ 19 $_SESSION['products']=serialize($_POST['form_products']); 20 } 21 echo "<p>your products have been registered!</p>"; 22 } 23 ?> 24 <form method="post" action="<?php echo $_SERVER['PHP_SELF']; ?>"> 25 <p> 26 <label for = "form_products">Select some products:</label><br /> 27 <select id="form_products" name="form_products[]" multiple="multiple" size="3"> 28 <option value="Sonic Screwdriver">Sonic Screwdriver</option> 29 <option value="Hal 2000">Hal 2000</option> 30 <option value="Tardis">Tardis</option> 31 <option value="Transportor">Transportor</option> 32 </select> 33 </p> 34 <button type="submit" name="submit" value="choose">Submit Form</button> 35 </form> 36 <p><a href="session2.php">go to content page</a> </p> 37 </body> 38 </html>
session2.php
1 <!DOCTYPE html> 2 <html> 3 <head> 4 <title>Storing an array with a session</title> 5 </head> 6 <body> 7 <h1>Product Choice Page</h1> 8 <?php 9 if(isset($_POST['form_products'])){ 10 if(!empty($_SESSION['products'])){ 11 $products = array_unique( 12 array_merge(unserialize($_SESSION['products']), $_POST['form_products'])); 13 $_SESSION['products']=serialize($products); 14 } 15 else{ 16 $_SESSION['products']=serialize($_POST['form_products']); 17 } 18 echo "<p>your products have been registered!</p>"; 19 } 20 ?> 21 <form method="post" action="<?php echo $_SERVER['PHP_SELF']; ?>"> 22 <p> 23 <label for = "form_products">Select some products:</label><br /> 24 <select id="form_products" name="form_products[]" multiple="multiple" size="3"> 25 <option value="Sonic Screwdriver">Sonic Screwdriver</option> 26 <option value="Hal 2000">Hal 2000</option> 27 <option value="Tardis">Tardis</option> 28 <option value="Transportor">Transportor</option> 29 </select> 30 </p> 31 <button type="submit" name="submit" value="choose">Submit Form</button> 32 </form> 33 <p><a href="session2.php">go to content page</a> </p> 34 </body> 35 </html>