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我有簡單單，設置PDO對象從工廠類，在第一盤 的PDO對象setes它的價值就好了。但是當我調用單第二方法（即設置SQL調用）我看到的PDO對象未設置。 這裏是示例代碼： singleton類：PHP單局部變量調用第二種方法時失去價值
<?php
require_once ('DBFactory.php');
require_once ('Config.php');
class DBHandler {
private static $instance;
private $pdo = NULL;
private function __construct()
{
}
public function ConnectToDb($db_name)
{
$ConfigObj = new Config();
$SelectedDbConfig = $ConfigObj->GetSelectedDB($db_name);
$pdo = DBFactory::GetDBConnection(Config::DB_TYPE_MYSQL,$SelectedDbConfig["host"],
$SelectedDbConfig["db"],
$SelectedDbConfig["user"],
$SelectedDbConfig["pass"]);
if(!isset($pdo))
return false;
return true;
}
public function SetUserNameAndPass($user,$pass)
{
$query_add_user = "INSERT INTO (name ,password) values ('$user' , '$pass') ";
if(!$this->ExecQuery($query_add_user))
{
echo "sql failed";
}
}
public function ExecQuery($query_str)
{
$statment_handler = $this->pdo->prepare($query_str);
if(!$statment_handler) {
throw new ErrorException($this->pdo->error, $this->pdo->errno);
}
if($statment_handler->execute())
return true;
return false;
}
public static function GetInstance()
{
if (!isset(self::$instance)) {
$className = __CLASS__;
self::$instance = new $className;
}
return self::$instance;
}
}
?>
這裏我設置，並調用singletone並在SetUserNameAndPass方法即時得到 致命錯誤：調用一個成員函數準備（）一個非對象在調試程序檢查後誤差 我可以看到，PDO對象是空的。
<?php
require_once ('DBFactory.php');
require_once ('Config.php');
class DBHandler {
private static $instance;
private $pdo = NULL;
private function __construct()
{
}
public function ConnectToDb($db_name)
{
$ConfigObj = new Config();
$SelectedDbConfig = $ConfigObj->GetSelectedDB($db_name);
$pdo = DBFactory::GetDBConnection(Config::DB_TYPE_MYSQL,$SelectedDbConfig["host"],
$SelectedDbConfig["db"],
$SelectedDbConfig["user"],
$SelectedDbConfig["pass"]);
if(!isset($pdo))
return false;
return true;
}
public function SetUserNameAndPass($user,$pass)
{
$query_add_user = "INSERT INTO (name ,password) values ('$user' , '$pass') ";
if(!$this->ExecQuery($query_add_user))
{
echo "sql failed";
}
}
public function ExecQuery($query_str)
{
$statment_handler = $this->pdo->prepare($query_str);
if(!$statment_handler) {
throw new ErrorException($this->pdo->error, $this->pdo->errno);
}
if($statment_handler->execute())
return true;
return false;
}
public static function GetInstance()
{
if (!isset(self::$instance)) {
$className = __CLASS__;
self::$instance = new $className;
}
return self::$instance;
}
}
?>
<?php
require_once ('DBHandler.php');
//Retrieve form data.
//GET - user submitted data using AJAX
//POST - in case user does not support javascript, we'll use POST instead
$user = ($_GET['user']) ? $_GET['user'] : $_POST['user'];
$password = ($_GET['password']) ?$_GET['password'] : $_POST['password'];
//flag to indicate which method it uses. If POST set it to 1
if($_POST)
{
$post=1;
}
//Simple server side validation for POST data, of course, you should validate the email
if (!$user) $errors[count($errors)] = 'Please enter your user.';
if (!$password) $errors[count($errors)] = 'Please enter your password.';
$DBhandler_st = NULL;
if (!$errors) {
if ($_POST) {
$DBhandler_st = DBHandler::GetInstance();
if($DBhandler_st->ConnectToDb("db1"))
{
$user = trim($user);
$password = trim($password);
$DBhandler_st->SetUserNameAndPass($user,$password);
echo '1';
}
else {
echo '0';
}
}
} else {
//display the errors message
for ($i=0; $i<count($errors); $i++) echo $errors[$i] . '<br/>';
echo '<a href="admin.html">Back</a>';
exit;
}
?>