PHP MVC模式在网站架构中的实现分析

＜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; 
 } 
} 
?＞