封装、继承、多态为oop的三大核心特性，我们可以根据这些特性，使用工厂模式。
工厂模式：在有些时候，需要创建基类的子类的一个具体实例，可以通过工厂模式实现，通常一个工厂类拥有一个静态的方法，用来接收一些输入，并根据输入决定创建哪个类的实例（通常是一个子类）
假设，我们有一个这样的需求，网站有3种用户：管理员，会员，游客，这3种用户具有不同的权限和后台管理页面，通常管理员的后台是固定的，游客和会员根据类型调用不同的页面
1，通过oop基本的3大特性，实现用户分层，权限和后台进行定制
1 abstract class User { 2 ????protected $name = NULL; 3 ????function __construct( $name ) { 4 ????????$this->name = $name; 5 ????} 6 ????function getName(){ 7 ????????return $this->name; 8 ????} 9 ????function hasReadPermission(){10 ????????return true;11 ????}12 ????function hasModifyPermission(){13 ????????return false;14 ????}15 ????function hasDeletePermission(){16 ????????return false;17 ????}18 ????function wantsFlashInterface(){19 ????????return true;20 ????}21 }22 23 class GuestUser extends User {24 }25 26 class CustomerUser extends User {27 ????function hasModifyPermission(){28 ????????return true;29 ????}30 }31 32 class AdminUser extends User {33 ????function hasModifyPermission(){34 ????????return true;35 ????}36 ????function hasDeletePermission(){37 ????????return true;38 ????}39 ????function wantsFlashInterface(){40 ????????return false;41 ????}42 }二，通过工厂类控制创建对应的子类实例
class UserFactory { ???private static $users = array( "ghostwu" => "admin", "lisi" => "guest", "wangwu" => "customer" ); ???static function create( $name ){ ???????if( !isset( self::$users[$name] ) ) { ???????????echo $name . ",这个用户不存在" . PHP_EOL; ???????????return ; ???????} ???????switch( self::$users[$name] ){ ???????????case "admin": ???????????????return new AdminUser( $name ); ???????????case "guest": ???????????????return new GuestUser( $name ); ???????????case "customer": ???????????????return new CustomerUser( $name ); ???????????default: ???????????????return "不存在该用户类型"; ???????} ???}}三、结合之前的封装，完善业务
function boolToStr( $b ){ ???if( $b == true ){ ???????return "yes" . PHP_EOL; ???}else { ???????return "no" . PHP_EOL; ???}}function displayPermissions( User $obj ){ ???echo $obj->getName() . ",该用户权限:" . PHP_EOL; ???????echo "read:" . ?boolToStr( $obj->hasReadPermission() ); ???echo "modify:" . boolToStr( $obj->hasModifyPermission() ); ???echo "delete:" . boolToStr( $obj->hasDeletePermission() );}function displayRequirements( User $obj ){ ???echo "刷新后台界面:" . boolToStr( $obj->wantsFlashInterface() );}$logins = array( "ghostwu", "lisi", "wangwu" );foreach( $logins as $login ) { ???displayPermissions( UserFactory::create( $login ) ); ???displayRequirements( UserFactory::create( $login ) ); ???echo "----------------------------" . PHP_EOL;}
php设计模式-工厂模式
原文地址：https://www.cnblogs.com/ghostwu/p/8461308.html