在站点迁移到php 5.6和mysql 5.6之后，获取数据库连接失败问题

Question

网站迁移后，人们收到数据库错误。

<?php

final class MySQL {     私人$连接;

public function __construct($hostname, $username, $password, $database) {
    if (!$this->connection = mysql_connect($hostname, $username, $password)) {
        exit('Error: Could not make a database connection using ' . $username . '@' . $hostname);
    }


if (!mysql_select_db($database, $this->connection)) {
        exit('Error: Could not connect to database ' . $database);
    }

    mysql_query("SET NAMES 'utf8'", $this->connection);
    mysql_query("SET CHARACTER SET utf8", $this->connection);
    mysql_query("SET CHARACTER_SET_CONNECTION=utf8", $this->connection);
    mysql_query("SET SQL_MODE = ''", $this->connection);
}



public function query($sql) {
    $resource = mysql_query($sql, $this->connection);