PHP简易MVC框架实现教程 – 从零构建Web应用架构

什么是MVC模式？

MVC（Model-View-Controller）是一种软件设计模式，将应用程序分为三个核心组件：模型（数据处理）、视图（用户界面）和控制器（业务逻辑）。这种分离提高了代码的可维护性和可扩展性。

创建项目结构

/myapp
  /app
    /controllers
      - HomeController.php
    /models
      - User.php
    /views
      /home
        - index.php
  /core
    - Router.php
    - Controller.php
    - Model.php
  /public
    - index.php
    - .htaccess
  - config.php

实现核心组件

1. 路由系统 (Router.php)

<?php
class Router {
    private $routes = [];
    
    public function addRoute($route, $controller, $action) {
        $this->routes[$route] = ['controller' => $controller, 'action' => $action];
    }
    
    public function dispatch($uri) {
        if (array_key_exists($uri, $this->routes)) {
            $controller = $this->routes[$uri]['controller'];
            $action = $this->routes[$uri]['action'];
            
            $controllerFile = "app/controllers/" . $controller . ".php";
            if (file_exists($controllerFile)) {
                require_once $controllerFile;
                $controllerClass = new $controller();
                $controllerClass->$action();
            } else {
                throw new Exception("控制器不存在: " . $controller);
            }
        } else {
            throw new Exception("路由未定义: " . $uri);
        }
    }
}
?>

2. 基础控制器 (Controller.php)

<?php
class Controller {
    public function model($model) {
        require_once 'app/models/' . $model . '.php';
        return new $model();
    }
    
    public function view($view, $data = []) {
        extract($data);
        require_once 'app/views/' . $view . '.php';
    }
}
?>

3. 基础模型 (Model.php)

<?php
class Model {
    protected $db;
    
    public function __construct() {
        $this->db = new PDO('mysql:host=localhost;dbname=test', 'username', 'password');
        $this->db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    }
    
    protected function query($sql, $params = []) {
        $stmt = $this->db->prepare($sql);
        $stmt->execute($params);
        return $stmt;
    }
}
?>

创建示例应用

1. 首页控制器 (HomeController.php)

<?php
require_once 'core/Controller.php';

class HomeController extends Controller {
    public function index() {
        $data = [
            'title' => '欢迎使用MVC框架',
            'message' => '这是通过MVC模式渲染的页面'
        ];
        $this->view('home/index', $data);
    }
    
    public function about() {
        $user = $this->model('User');
        $users = $user->getAllUsers();
        
        $data = [
            'title' => '关于我们',
            'users' => $users
        ];
        $this->view('home/about', $data);
    }
}
?>

2. 用户模型 (User.php)

<?php
require_once 'core/Model.php';

class User extends Model {
    public function getAllUsers() {
        $result = $this->query("SELECT id, name, email FROM users");
        return $result->fetchAll(PDO::FETCH_ASSOC);
    }
    
    public function getUserById($id) {
        $result = $this->query("SELECT id, name, email FROM users WHERE id = ?", [$id]);
        return $result->fetch(PDO::FETCH_ASSOC);
    }
}
?>

3. 视图文件 (index.php)

<!DOCTYPE html>
<html>
<head>
    <title><?php echo $title; ?></title>
</head>
<body>
    <h1><?php echo $title; ?></h1>
    <p><?php echo $message; ?></p>
    <a href="/about" rel="external nofollow" >关于我们</a>
</body>
</html>

4. 入口文件 (public/index.php)

<?php
require_once '../core/Router.php';

// 初始化路由
$router = new Router();

// 添加路由规则
$router->addRoute('/', 'HomeController', 'index');
$router->addRoute('/about', 'HomeController', 'about');

// 获取请求URI并去除查询字符串
$requestUri = strtok($_SERVER['REQUEST_URI'], '?');

// 分发请求
try {
    $router->dispatch($requestUri);
} catch (Exception $e) {
    echo "错误: " . $e->getMessage();
}
?>

5. URL重写配置 (public/.htaccess)

RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php [QSA,L]

框架使用示例

添加新功能

要添加新功能，只需遵循以下步骤：

在Router中添加新路由
创建对应的控制器和方法
如果需要数据操作，创建模型
创建视图文件展示内容

示例：添加用户详情页

// 在Router中添加路由
$router->addRoute('/user/{id}', 'UserController', 'show');

// 创建UserController
class UserController extends Controller {
    public function show($id) {
        $userModel = $this->model('User');
        $user = $userModel->getUserById($id);
        
        $this->view('user/show', ['user' => $user]);
    }
}

// 创建视图文件 app/views/user/show.php