mysql 连接闪断自动重连的方法(用在后台运行中的PHP代码)详解数据库

mysql 连接闪断自动重连的方法(用在后台运行中的PHP代码)
当mysql断开连接 $_instance这个还是有值得 所以会报错 MySQL server has gone away 这个地方需要捕捉异常才可以或许到
需要 清空连接 $_instance 这样就可以重新连接 就会报错了

<?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 {
 $h_param = array(
 PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION, //设置错误级别
 );
 if ($charset != '') {
 $h_param[PDO::MYSQL_ATTR_INIT_COMMAND] = 'SET NAMES ' . $charset; //设置默认编码
 }
 
 if ($pconnect) {
 $h_param[PDO::ATTR_PERSISTENT] = true; //是否是长连接
 }
 $conn = new PDO($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 $e->getMessage().PHP_EOL;
 self::reset_connect($e->getMessage()); // 出错时调用重置连接
 }
 $result = $sth->fetchAll(PDO::FETCH_ASSOC);
 return $result;
 }
 
 // 重置连接
 public static function reset_connect($err_msg){
 if(strpos($err_msg, 'MySQL server has gone away')!==false){
 self::$_instance = null;
 }
 }
 
}
?>