MVC模式的PHP实现

MVC模式在网站架构中十分常见。它允许我们建立一个三层结构的应用程式，从代码中分离出有用的层，帮助设计师和开发者协同工作以及提高我们维护和扩展既有程式的能力。

<p>{some_text}</p> 
<p>{some_more_text}</p>

<?php 
switch ($_GET['viewpage']) { 
    case "news": 
        $page=new NewsRenderer; 
    break; 
    case "links": 
        $page=new LinksRenderer; 
    break; 
    default: 
        $page=new HomePageRenderer; 
    break; 
} 
$page->display(); 
?>

<?php 
/** 
*  A simple class for querying MySQL 
*/ 
class DataAccess { 
    /** 
    * Private 
    * $db stores a database resource 
    */ 
    var $db; 
    /** 
    * Private 
    * $query stores a query resource 
    */ 
    var $query; // Query resource 

    //! A constructor. 
    /** 
    * Constucts a new DataAccess object 
    * @param $host string hostname for dbserver 
    * @param $user string dbserver user 
    * @param $pass string dbserver user password 
    * @param $db string database name 
    */ 
    function DataAccess ($host,$user,$pass,$db) { 
        $this->db=mysql_pconnect($host,$user,$pass); 
        mysql_select_db($db,$this->db); 
    } 

    //! An accessor 
    /** 
    * Fetches a query resources and stores it in a local member 
    * @param $sql string the database query to run 
    * @return void 
    */ 
    function fetch($sql) { 
        $this->query=mysql_unbuffered_query($sql,$this->db); // Perform query here 
    } 

    //! An accessor 
    /** 
    * Returns an associative array of a query row 
    * @return mixed 
    */ 
    function getRow () { 
        if ( $row=mysql_fetch_array($this->query,MYSQL_ASSOC) ) 
            return $row; 
        else 
            return false; 
    } 
} 
?>

<?php 
/** 
*  Fetches "products" from the database 
*/ 
class ProductModel { 
    /** 
    * Private 
    * $dao an instance of the DataAccess class 
    */ 
    var $dao; 

    //! A constructor. 
    /** 
    * Constucts a new ProductModel object 
    * @param $dbobject an instance of the DataAccess class 
    */ 
    function ProductModel (&$dao) { 
        $this->dao=& $dao; 
    } 

    //! A manipulator 
    /** 
    * Tells the $dboject to store this query as a resource 
    * @param $start the row to start from 
    * @param $rows the number of rows to fetch 
    * @return void 
    */ 
    function listProducts($start=1,$rows=50) { 
        $this->dao->fetch("SELECT * FROM products LIMIT ".$start.", ".$rows); 
    } 

    //! A manipulator 
    /** 
    * Tells the $dboject to store this query as a resource 
    * @param $id a primary key for a row 
    * @return void 
    */ 
    function listProduct($id) { 
        $this->dao->fetch("SELECT * FROM products WHERE PRODUCTID='".$id."'"); 
    } 

    //! A manipulator 
    /** 
    * Fetches a product as an associative array from the $dbobject 
    * @return mixed 
    */ 
    function getProduct() { 
        if ( $product=$this->dao->getRow() ) 
            return $product; 
        else 
            return false; 
    } 
} 
?>

<?php 
/** 
*  Binds product data to HTML rendering 
*/ 
class ProductView { 
    /** 
    * Private 
    * $model an instance of the ProductModel class 
    */ 
    var $model; 

    /** 
    * Private 
    * $output rendered HTML is stored here for display 
    */ 
    var $output; 

    //! A constructor. 
    /** 
    * Constucts a new ProductView object 
    * @param $model an instance of the ProductModel class 
    */ 
    function ProductView (&$model) { 
        $this->model=& $model; 
    } 

    //! A manipulator 
    /** 
    * Builds the top of an HTML page 
    * @return void 
    */ 
    function header () { 

    } 

    //! A manipulator 
    /** 
    * Builds the bottom of an HTML page 
    * @return void 
    */ 
    function footer () { 

    } 

    //! A manipulator 
    /** 
    * Displays a single product 
    * @return void 
    */ 
    function productItem($id=1) { 
        $this->model->listProduct($id); 
        while ( $product=$this->model->getProduct() ) { 
             // Bind data to HTML 
        } 
    } 

    //! A manipulator 
    /** 
    * Builds a product table 
    * @return void 
    */ 
    function productTable($rownum=1) { 
        $rowsperpage='20'; 
        $this->model->listProducts($rownum,$rowsperpage); 
        while ( $product=$this->model->getProduct() ) { 
             // Bind data to HTML 
        } 
    } 

    //! An accessor 
    /** 
    * Returns the rendered HTML 
    * @return string 
    */ 
    function display () { 
        return $this->output; 
    } 
} 
?>

<?php 
/** 
*  Controls the application 
*/ 
class ProductController extends ProductView { 

    //! A constructor. 
    /** 
    * Constucts a new ProductController object 
    * @param $model an instance of the ProductModel class 
    * @param $getvars the incoming HTTP GET method variables 
    */ 
    function ProductController (&$model,$getvars=null) { 
        ProductView::ProductView($model); 
        $this->header(); 
        switch ( $getvars['view'] ) { 
            case "product": 
                $this->productItem($getvars['id']); 
                break; 
            default: 
                if ( empty ($getvars['rownum']) ) { 
                    $this->productTable(); 
                } else { 
                    $this->productTable($getvars['rownum']); 
                } 
                break; 
        } 
        $this->footer(); 
    } 
} 
?>

<?php 
require_once('lib/DataAccess.php'); 
require_once('lib/ProductModel.php'); 
require_once('lib/ProductView.php'); 
require_once('lib/ProductController.php'); 

$dao=& new DataAccess ('localhost','user','pass','dbname'); 
$productModel=& new ProductModel($dao); 
$productController=& new ProductController($productModel,$_GET); 
echo $productController->display(); 
?>

$this->{$_GET['method']}($_GET['param']); 

"index.php?class=ProductView&method=productItem&id=4"

$view=new $_GET['class']; 
$view->{$_GET['method']($_GET['id']);