php中session 入库的实现

ini_set("session.save_handler","user");
//session.gc_probability = 1 分子
ini_set("session.gc_probability",1);
//session.gc_divisor = 1000 分母
ini_set("session.gc_divisor",2);
//session.gc_maxlifetime = 1440 垃圾回收时间，session有效期

session_set_save_handler( "open","close","read","write","destroy","gc" );
//1.开启session机制
//连接数据库
function open($savePath,$sessionName){
mysql_connect("localhost","root","root");
mysql_select_db("session");
mysql_query("set names utf8");
}
function close(){
echo "close<br>";
}
function read($sessionId){
$sql = "select * from session where sessionid='".$sessionId."'";
$re = mysql_query($sql);
$sessdata = mysql_fetch_assoc($re);

//返回session存储的数据
return $sessdata["sessiondata"];
}
function write($sessionId,$data){

//如果sessionid不存在，插入新纪录，存在就更新
/*$sql = "select * from session where sessionid='".$sessionId."'";
$re = mysql_query($sql);
if(mysql_num_rows($re) > 0){
$sql = "update session set sessiondata='".$data."' where sessionid='".$sessionId."'";
}else{
$sql = "insert into session(sessionid,sessiondata,sessiontime) values('".$sessionId."','".$data."',".time().")";

}
if(!mysql_query($sql)){
echo mysql_error();
}else{
return true;
}
*/

//用replace语法解决上述操作
$sql = "replace into session(sessionid,sessiondata,sessiontime) values('".$sessionId."','".$data."',".time().")";
if(!mysql_query($sql)){
echo mysql_error();
}else{
return true;
}

}
//根据sessionid销毁当前的session
function destroy($sessionId){
echo "destroy<br>";
}

//删除过期的所有session
function gc($lifetime){
echo "gc<br>";
}
session_start();

$_SESSION["name"] = "ghj";
var_dump($_SESSION);