返回对象中的数据解析

Question

我对OOP非常陌生，所以这可能是个愚蠢的问题。

我有一个数据库抽象层类，如下所示：

class DB {
public static $instance = null;

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

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

public static function getInstance() {
    // Already an instance of this? Return, if not, create.
    if(!isset(self::$instance)) {
        self::$instance = new DB();
    }
    return self::$instance;
}

public function query($sql, $params = array()) {

    $this->_error = false;

    if($this->_query = $this->_pdo->prepare($sql)) {
        $x = 1;
        if(count($params)) {
            foreach($params as $param) {
                $this->_query->bindValue($x, $param);
                $x++;
            }
        }

        if($this->_query->execute()) {
            $this->_results = $this->_query->fetchAll(PDO::FETCH_OBJ);
            $this->_count = $this->_query->rowCount();
        } else {
            $this->_error = true;
        }
    }

    return $this;
}




public function results() {
    // Return result object
    return $this->_results;
}



public function count() {
    // Return count
    return $this->_count;
}

public function error() {
    return $this->_error;
}

当我从另一个文件调用查询方法时

    $users = DB::getInstance()->query('SELECT * FROM users');
var_dump($users);

我以这种格式获取用户数据：

DB对象( _pdo:DB:private => PDO Object () _query:DB:private => PDOStatement Object )( queryString => SELECT * FROM sheild ) _error:DB:private => _results:DB:private => >Array ( => stdClass Object ( sid => 1 name => Scutum heavier => 55 defense => 90 >description => stdClass PDOStatement queryString PDOStatement Object )1 PDOStatement Object ( sid 2 name >修改后的scutum重量65描述改良更重的潜水>提供更多保护)2 en26# sid 3#名称圆形Parmula >重量30 #国防3060描述=>小型盾牌用于色雷斯战士) >3 => stdClass对象( sid => 4 name =>矩形Parmula => => 40 >=> 75 description => 75 => stdClass Object )4 => stdClass Object ( sid => 5 >name => Hoplon => 20国防=> 35 =>35 description =>)5 => stdClass Object ( sid => 6 name => Aspis >重量=> 35国防=> 50描述=>铁版) >_count:DB:private => 6)

为什么这段代码会起作用？

    foreach ($shields as $shield) {
    echo $sheild->name;
}

我遗漏了什么？

Answer 1

你有一个结果方法，使用它。不过，我不确定您是否可以在类之外迭代私有对象。

$results = $users->results();
foreach($results as $shield){
    echo $user->name;
    //your code here
}

或将DB类中的$this->_结果从私有更改为public