__construct（）期望参数2为字符串

Question

I'm trying to create a loging/registration system but I got this warning error along the way and I couldn't fix it.

Warning: PDO::__construct() expects parameter 2 to be string

Here's my code so far

DB.php

<?php
class DB  {
    private static $_instance = null;

    private $_pdo,
            $_query = null,
            $_error = false,
            $_results,
            $_count = 0;

    private function __construct()  {
        try  {
            $this->_pdo = new PDO('mysql:host=' . Config::get('mysql/host').';'.
                                                               'dbname='.Config::get('mysql/db'),
                                                               Config::get('msql/username'), 
                                                               Config::get('msql/password')); 
        }  catch(PDOExeption $e) {
            die($e->getMessage()); 
        }
    }

    public static function getInstance()  { 
        if (!isset(self::$_instance)){ 
            self::$_instance = new DB(); 
        }
        return self::$_instance;
    }
}

init.php

<?php
session_start();

$GLOBALS['config'] = array (
    'mysql' => array(
        'host' => '127.0.01',
        'username' => 'root',
        'password' => '',
        'db' => 'lr'
    ),
    'remember' => array(
        'cookie_name' => 'hash',
        'cookie_expiry' => 604800
    ),
    'session' => array(
        'session_name' => 'user'
    )
);

spl_autoload_register(function($class){ 
    require_once 'classes/' .  $class  . '.php';
});

require_once 'functions/sanitize.php';
?>

index.php

<?php
require 'core/init.php';

DB::getInstance();
?>

Answer 1

Typo

Config::get('msql/username'), 

Should be

Config::get('mysql/username'), 
              ^

Same for password. With that typo you are getting an invalid value, hence the error.