php数据库处理类

<?php
class Database {
    private $host = 'localhost';
    private $db_name = 'test_db';
    private $username = 'root';
    private $password = '';
    public $conn;

    public function getConnection() {
        $this->conn = null;
        try {
            $this->conn = new PDO("mysql:host=" . $this->host . ";dbname=" . $this->db_name, $this->username, $this->password);
            $this->conn->exec("set names utf8");
        } catch(PDOException $exception) {
            echo "Connection error: " . $exception->getMessage();
        }
        return $this->conn;
    }
}

$db = new Database();
$connection = $db->getConnection();

if ($connection) {
    try {
        $stmt = $connection->prepare("SELECT * FROM users WHERE id = :id");
        $stmt->bindParam(':id', $id);
        $id = 1; // 示例ID
        $stmt->execute();
        $user = $stmt->fetch(PDO::FETCH_ASSOC);
        print_r($user);
    } catch(PDOException $exception) {
        echo "Query error: " . $exception->getMessage();
    }
}
?>