创建定制mysql会话处理器

1.创建存储数据的mysql表

DROP TABLE IF EXISTS `session`.`sessioninfo`;
CREATE TABLE  `session`.`sessioninfo` (
  `SID` char(32) NOT NULL,
  `expiration` int(10) unsigned NOT NULL,
  `value` text NOT NULL,
  PRIMARY KEY  (`SID`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

2.创建6个定制处理器函数,并用session_set_save_handler注册

mysqlsessionhandlers.php

<?php
/*
 * mysql_session_open()
 * opens a persistent server connectiona and selects the database.
 */
function mysql_session_open($session_path,$session_name){
 mysql_connect("localhost","root","root") or die("Can't connect to MySQL server!");
 mysql_select_db("session") or die("Can't select MySQL session database");
}
/*
 * mysql_session_close()
 * Doesn't actually do anything since the server connection is
 * persitne.Keep in mind that although this function
 * doesn't do anything in my particular implomentation,it
 * must nonetheless be defined
 */
function mysql_session_close(){
 return 1;
}
/*
 * mysql_session_select()
 * Reads the session data from the database
 */
function mysql_session_select($SID){
 $query="select value from sessionfinfo where SID='$SID' and expiration >".time();
 $result=mysql_query($query);
 if(mysql_num_rows($result)){
  $row=mysql_fetch_assoc($result);
  $value=$row['value'];
  return $value;
 }else{
  return "";
 }
}
/*
 * mysql_session_write()
 * This function writes the session data to the database.
 * If that SID already exists,then the existing data will be updated.
 */
function mysql_session_write($SID,$value){
 $lifetime=get_cfg_var("session.gc_maxlifetime");
 $expiration=time()+$lifetime;
 $query="insert into sessioninfo values('$SID','$expiration','$value')";
 $result=mysql_query($query);
 if(!$result){
  $query="update sessioninfo set expiration='$expiration' value='$value' where SID='$SID' and expiration>".time();
  $result=mysql_query($query);
 }
}
/*
 * mysql_session_destory()
 * Deletes all session information having input SID(only on row)
 */
function mysql_session_destroy($SID){
 $query="delete from sessioninfo where SID='$SID";
 $result=mysql_query($query);
}

function mysql_session_garbage_collect($lifetime){
 $query="delete from sessioninfo where expiration<".time()-$lifetime;
 $result=mysql_query($query);
 return mysql_affected_rows($result);
}
session_set_save_handler("mysql_session_open","mysql_session_close","mysql_session_select","mysql_session_write","mysql_session_destroy","mysql_session_garbage_collect");

?>
3.测试

<?php

include "mysqlsessionhandlers.php";

session_start();
$_SESSION["name"]="jickcai";

?>

会看到数据已插入到数据库里.