在 MySQL 服务器上重新连接已经消失

2021-12-26 00:00:00 error-handling php mysql pdo

如何修改此类以捕获 MySQL 服务器离开的异常并重新连接?

How can I modify this class to catch exception where MySQL Server Goes Away, and reconnect?

<?php
class DBConn
{
private $conn;

public function __construct( $persistent = false )
{
    try
    {
        $this->conn = new PDO( "mysql:host=localhost;dbname=test", 'test', "hoollaahaoo" );
        $this->conn->exec( "SET CHARACTER SET utf8" );
        $this->conn->setAttribute( PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC ); 
        if ( $persistent )
            $this->conn->setAttribute( PDO::ATTR_PERSISTENT, true );
    }
    catch( PDOException $e )
    {
        return $e->getMessage();
    }
}

public function getConn()
{
    return $this->conn;
}
}

推荐答案

你可能需要像这样创建自己的类

you probably will need to make your own class like this one

  1. 从__construct
    2. 中删除try/except
  2. 然后像这样连接到你的数据库:

$conn = null;
$limit = 10;
$counter = 0;
while (true) {
  try {
    $conn = DBConn();
    break;
  }
  catch (Exception $e) {
    $conn = null;
    $counter++;
    if ($counter == $limit)
      throw $e;
  }

}

编辑 1:

但是如果你说你的服务器消失了......那么可能是这样的

but if you say that your server goes away.... then may be smth like this

protected function _connect( $persistent = false ) {
$conn = null;
$limit = 10;
$counter = 0;
while (true) {
  try {
        $this->conn = new PDO( "mysql:host=localhost;dbname=test", 'test', "hoollaahaoo" );
        $this->conn->exec( "SET CHARACTER SET utf8" );
        $this->conn->setAttribute( PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC ); 
        if ( $persistent )
            $this->conn->setAttribute( PDO::ATTR_PERSISTENT, true );
}
  catch (Exception $e) {
    $conn = null;
    $counter++;
    if ($counter == $limit)
      throw $e;
  }
}

public function __construct( $persistent = false )
{
    $this->_connect($persistent);
}

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