mysql_ping() 檢查到伺服器的連線是否正常。如果到伺服器的連線可用，則傳回true，否則傳回false。
但PDO不支援mysql_ping()方法，因此需要自行寫程式碼模擬mysql_ping()方法，檢查連線是否可用。
<?php/**
* 检查连接是否可用
* @param Link $dbconn 数据库连接
* @return Boolean
*/function pdo_ping($dbconn){
try{ $dbconn->getAttribute(PDO::ATTR_SERVER_INFO);
} catch (PDOException $e) { if(strpos($e->getMessage(), 'MySQL server has gone away')!==false){ return false;
}
} return true;
}?>CREATE TABLE `user` ( `id` int(11) unsigned NOT NULL AUTO_INCREMENT, `name` varchar(20) NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
2.插入測試資料
insert into user(name) values('fdipzone'),('xfdipzone'),('terry');mysql> select * from user; +----+-----------+| id | name | +----+-----------+| 1 | fdipzone | | 2 | xfdipzone || 3 | terry | +----+-----------+
3.示範檔案
db.php
#<?php// 数据库操作类class DB{
// 保存数据库连接
private static $_instance = null; // 连接数据库
public static function get_conn($config){
if(isset(self::$_instance) && !empty(self::$_instance)){ return self::$_instance;
} $dbhost = $config['host']; $dbname = $config['dbname']; $dbuser = $config['user']; $dbpasswd = $config['password']; $pconnect = $config['pconnect']; $charset = $config['charset']; $dsn = "mysql:host=$dbhost;dbname=$dbname;"; try { $h_param = array(
PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
); if ($charset != '') { $h_param[PDO::MYSQL_ATTR_INIT_COMMAND] = 'SET NAMES ' . $charset; //設置默認編碼
} if ($pconnect) { $h_param[PDO::ATTR_PERSISTENT] = true;
} $conn = new PDO($dsn, $dbuser, $dbpasswd, $h_param);
} catch (PDOException $e) { throw new ErrorException('Unable to connect to db server. Error:' . $e->getMessage(), 31);
} self::$_instance = $conn; return $conn;
} // 执行查询
public static function query($dbconn, $sqlstr, $condparam){
$sth = $dbconn->prepare($sqlstr); try{ $sth->execute($condparam);
} catch (PDOException $e) { echo $e->getMessage().PHP_EOL;
} $result = $sth->fetchAll(PDO::FETCH_ASSOC); return $result;
} // 重置连接
public static function reset_connect(){
self::$_instance = null;
}
}?>##test.php
<?phprequire 'db.php';// 数据库设定$config = array( 'host' => 'localhost', 'dbname' => 'user', 'user' => 'root', 'password' => '', 'pconnect' => 0, 'charset' => '');// 循环执行while(true){ // 创建数据连接
$dbconn = DB::get_conn($config); // 判断连接是否有效
$status = pdo_ping($dbconn); if($status){ echo 'connect ok'.PHP_EOL;
}else{ echo 'connect failure'.PHP_EOL; // 重置连接
DB::reset_connect(); $dbconn = DB::get_conn($config);
} // 执行查询
$sqlstr = 'select * from user where id=?'; $condparam = array(mt_rand(1,3)); $data = DB::query($dbconn, $sqlstr, $condparam);
print_r($data); // 延时10秒
echo 'sleep 10'.PHP_EOL.PHP_EOL;
sleep(10);
}/**
* 检查连接是否可用
* @param Link $dbconn 数据库连接
* @return Boolean
*/function pdo_ping($dbconn){
try{ $dbconn->getAttribute(PDO::ATTR_SERVER_INFO);
} catch (PDOException $e) { if(strpos($e->getMessage(), 'MySQL server has gone away')!==false){ return false;
}
} return true;
}?>
mysql.server stopShutting down MySQL .... SUCCESS! mysql.server start Starting MySQL SUCCESS!
connect okArray(
[0] => Array
(
[id] => 2
[name] => xfdipzone
)
)
sleep 10connect failureArray(
[0] => Array
(
[id] => 3
[name] => terry
)
)
sleep 10connect okArray(
[0] => Array
(
[id] => 3
[name] => terry
)
)
sleep 10以上是透過php中的PDO判斷連接是否可用的方法的詳細內容。更多資訊請關注PHP中文網其他相關文章！
