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);