session我们多半是保存在服务器中,但是今天有一个功能就是需要把session保存在数据库中,这样可以实现同ie多浏览了,php中session默认的存储方式是硬盘,php也可以改变默认的存储方式,主要使用到session_set_save_handler方法,下面分享下如何将session保存到MySql数据库中的具体代码.

1.建session表,代码如下:

1. CREATE TABLE `session` (
2. `sessionid` varchar(128) NOT NULL,
3. `uid` int(11) NOT NULL,
4. `data` mediumblob NOT NULL,
5. `timestamp` int(11) NOT NULL,
6. `ip` varchar(15) NOT NULL,
7. PRIMARY KEY (`sessionid`),
8. KEY `time_session` (`timestamp`,`sessionid`)
9. ) ENGINE=MyISAM DEFAULT CHARSET=utf8;
10. //uid 是保留字段

2.自定义session类,代码如下:

1. <?php
2. class CustomSession{
3. private static $db_host="localhost";
4. private static $db_user="root";
5. private static $db_password="";
6. private static $database="session";
7. private $conn;
8. public static function getInstance(){
9. static $instance=null;
10. if($instance==null){
11. $instance=new CustomSession();
12. }
13. return $instance;
14. }
15. public function __construct(){
16. session_set_save_handler(
17. array($this,"open"),
18. array($this,"close"),
19. array($this,"read"),
20. array($this,"write"),
21. array($this,"destroy"),
22. array($this,"gc")
23. );
24. }
25. public function __destruct(){
26. session_write_close();
27. }
28. public function open(){
29. $this->conn=mysql_connect(CustomSession::$db_host,CustomSession::$db_user,CustomSession::$db_password);
30. mysql_select_db(CustomSession::$database,$this->conn);
31. }
32. public function close(){
33. mysql_close($this->conn);
34. }
35. public function read($id){
36. $escaped_id=mysql_escape_string($id);
37. $res=$this->query("select * from `session` where `sessionid`='$escaped_id'");
38. if($row=mysql_fetch_assoc($res)){
39. $this->query("update `session` set `timetamp`=UTC_TIMESTAMP() where `sessionid`='$escaped_id'");
40. return $row['data'];
41. }
42. return "";
43. }
44. public function write($id,$data){
45. $query="replace into `session` (`sessionid`,`data`,`ip`,`timestamp`) values ('%s','%s','%s',UNIX_TIMESTAMP(UTC_TIMESTAMP()))";
46. $this->query(sprintf($query,mysql_escape_string($id),mysql_escape_string($data),$_SERVER["REMOTE_ADDR"]));
47. }
48. public function destroy($id){
49. $escaped_id=mysql_escape_string($id);
50. $res=$this->query("delete from `session` where `id`='$escaped_id'");
51. return (mysql_affected_rows($res)==1);
52. }
53. public function gc($lifetime){
54. $this->query("delete from `session` where UNIX_TIMESTAMP(UTC_TIMESTAMP())-`timestamp` > $lifetime");
55. }
56. public function query($query){
57. $res=mysql_query($query,$this->conn);
58. return $res;
59. }
60. }
61. ?>

3.测试程序,代码如下:

1. <?php
2. include('./CustomSession.class.php');
3. CustomSession::getInstance();
4. session_start();
5. $_SESSION['username']='feng';
6. print_r($_SESSION);
7. ?>

运行测试程序后,查看数据库可以发现session表中已经增加了session记录.