php oop pdo连接被拒绝？

我试图使用连接到数据库，但我得到这个错误，我在php终端上运行这个

我查阅了其他类似的资料，但没有找到我想要的答案

有什么建议或最佳实践吗

SQLSTATE[HY000] [2002] Connection refusedsomething went wrong

Db.php

<?php 

error_reporting(-1);

class Db{

    private $db_host;
    private $db_user;
    private $db_name;
    private $db_pass;

    public function __construct()
    {
        $this->db_host = "127.0.0.1";
        $this->db_user = "root";
        $this->db_pass = "";
        $this->db_name = "eli9";

        try{
            $pdo = new PDO("mysql:host=127.0.0.1;dbname=eli9", $this->db_user, $this->db_pass);
            $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

            echo "connected sucessfully \n";

        }

        catch(PDOexception $e){
            echo $e->getMessage();

            echo "something went wrong \n";
        }

    }


}

试试这个，对我有用

$pdo = new PDO("mysql:host=$this->db_host;dbname=$this->db_name", $this->db_user, $this->db_pass);

您将变量设置为
$this->db_host=“127.0.0.1”
，但未用于连接

在连接并使用
$db->setAttribute（PDO:：ATTR_ERRMODE，PDO:：ERRMODE_警告）之前，不要使用类来尝试此操作
检查是否有任何错误

还可以尝试端口
8889

try {
    $db = new PDO("mysql:host=127.0.0.1;port=3306,dbname=eli9", 'root', '');
    $db->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_WARNING);
    echo "connected";
    } 
catch (PDOException $e){
    echo $e->getMessage();
    }

在@addie代码的帮助下，我找到了问题所在，原因如下

1） 我最初没有使用端口号

2） 我把端口号改为8889，而不是3306

下面是Db.php的最终代码

<?php 

error_reporting(-1);

class Db{

    private $db_host;
    private $db_user;
    private $db_name;
    private $db_pass;

    public function __construct()
    {
        $this->db_host = "127.0.0.1";
        $this->db_user = "root";
        $this->db_pass = "root";
        $this->db_name = "eli9";

        try {
            $db = new PDO("mysql:host=127.0.0.1;port=8889,dbname=eli9", 'root', 'root');
            $db->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_WARNING);
            echo "connected";


        } 
        catch (PDOException $e){
            echo $e->getMessage();
        }


    }


}

谢谢，但还是不起作用，我最近更新到了PHP7，之前我用的是5.1，我想我知道了，你在用MAMP吗？
<?php 

error_reporting(-1);

class Db{

    private $db_host;
    private $db_user;
    private $db_name;
    private $db_pass;

    public function __construct()
    {
        $this->db_host = "127.0.0.1";
        $this->db_user = "root";
        $this->db_pass = "root";
        $this->db_name = "eli9";

        try {
            $db = new PDO("mysql:host=127.0.0.1;port=8889,dbname=eli9", 'root', 'root');
            $db->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_WARNING);
            echo "connected";


        } 
        catch (PDOException $e){
            echo $e->getMessage();
        }


    }


}