我正在尝试在PHP中创建一个简单的工厂模式演示。我不确定我的代码是否是最佳实践。似乎我有一些重复的代码，但我不确定如何改进它。基本上，我想创建3种类型的帐户(基本，高级和VIP(。请指教。多谢。
抽象类
abstract class User {
function __construct() {
$this->db= new Database('mysql','localhost','mvcdb','root','');
}
abstract function checkUser();
function showAccountCredit(){
return $this->credits;
}
function getUserName(){
return $this->username;
}
}
我有 3 种不同的用户帐户类型：
基本账户
class BasicUser extends User {
function __construct($username) {
parent::__construct();
$this->username=$username;
$this->credit='10';
$this->accountType='Basic Account';
$data=$this->checkUser();
if(!empty($data)){
echo 'The username: '.$this->username.' already exists<br>';
return false;
}
$array=array('username'=>$this->username, 'password'=>'password','credit'=> $this->credit,'accountType'=>$this->accountType);
$this->db->insert('user',$array);
}
function checkUser(){
$array=array(':username'=>$this->username);
$results=$this->db->select('SELECT * FROM USER WHERE username=:username',$array);
if(!empty($results)){
$this->credit=$results[0]['credit'];
$this->accountType=$results[0]['accountType'];
}
return $results;
}
function showAccountCredit() {
echo 'Username: '.$this->username.'<br>';
echo 'Account Credit: '.$this->credit.'<br>';
echo 'Account Type: '.$this->accountType;
}
}
高级帐户
class PremiumUser extends User {
function __construct($username) {
parent::__construct();
$this->username=$username;
$this->credit='100';
$this->accountType='Premium Account';
$data=$this->checkUser();
if(!empty($data)){
echo 'The username: '.$this->username.' already exists<br>';
return false;
}
$array=array('username'=>$this->username, 'password'=>'password','credit'=> $this- >credit,'accountType'=>$this->accountType);
$this->db->insert('user',$array);
}
function checkUser(){
$array=array(':username'=>$this->username);
$results=$this->db->select('SELECT * FROM USER WHERE username=:username',$array);
if(!empty($results)){
$this->credit=$results[0]['credit'];
$this->accountType=$results[0]['accountType'];
}
return $results;
}
function showAccountCredit() {
echo 'Username: '.$this->username.'<br>';
echo 'Account Credit: '.$this->credit.'<br>';
echo 'Account Type: '.$this->accountType.'<br>';
}
}
贵宾账户：
class VipUser extends User {
function __construct($username) {
parent::__construct();
$this->username=$username;
$this->credit='1000';
$this->accountType='VIP Account';
$data=$this->checkUser();
if(!empty($data)){
echo 'The username: '.$this->username.' already exists<br>';
return false;
}
$array=array('username'=>$this->username, 'password'=>'password','credit'=> $this->credit,'accountType'=>$this->accountType);
$this->db->insert('user',$array);
}
function checkUser(){
$array=array(':username'=>$this->username);
$results=$this->db->select('SELECT * FROM USER WHERE username=:username',$array);
if(!empty($results)){
$this->credit=$results[0]['credit'];
$this->accountType=$results[0]['accountType'];
}
return $results;
}
function showAccountCredit() {
echo 'Username: '.$this->username.'<br>';
echo 'Account Credit: '.$this->credit.'<br>';
echo 'Account Type: '.$this->accountType;
}
}
用户工厂类
class UserFactory {
static function create($username,$accountType){
$accountType = strtolower($accountType);
switch($accountType){
case 'basic': return new BasicUser($username);
case 'premium':return new PremiumUser($username);
case 'vip': return new VipUser($username);
default :return new BasicUser($username);
}
}
索引.php
$user1= UserFactory::create('Jerry', 'Vip');
$user1->showAccountCredit();
$user2= UserFactory::create('Bob', 'Basic');
$user2->showAccountCredit();
$user3= UserFactory::create('Betty', 'premium');
$user3->showAccountCredit();
与其有 3 种不同的用户实现，不如考虑 3 种不同的 "UserType" 实现。分离职责并组合对象。这是另一种行动模式，称为战略。
function showAccountCredit(){
return $this->type->showAccountCredit();
}
新类，UserType代表特殊行为，然后用户将包含其余的通用内容，减少您描述的重复(或至少大部分(
另一方面，工厂可用于从db加载对象：
class Loader{
private $userTypeFactory;
public function loadUser($id){
$userRow = $db->loadRow();
...
$userType = $userTypeFactory->$userRow["type"]();
return new User($userType);
}
}
class UserTypeFactory{
public function vip(){
return new VipUserType();
}
public function premium(){
return new PremiumUser();
}
}
您甚至可以更进一步，引入 IoC 框架。看看symfony2。哦，请不要使用开关，而是像我一样做，多态，动态调用。
编辑：
策略 == 包装行为。例如，如果您正在检查用户查看优质内容的权限，则通常如下所示：
class PagesController{
...
public function showPage($id){
...
if ($user->type == "premium" || $user->type == "vip"){
...
}
else if ($user->type == "credit"){
$user->credits--;
updateUser();
}
else{
die("You do not have permissions to see this content...");
}
... //render page
}
}
以下是使用"策略"的样子：
class PagesController{
...
public function showPage($id){
$page = ...;
$user->pageRequested($page);
//render page
}
}
class User{
private $userType;
public function pageRequested($page){
$this->userType->userRequestedPage($user, $page);
}
}
class VipUserType{
public function userRequestedPage($user, $page){
//do nothing
}
}
class PremiumUserType{
public function userRequestedPage($user, $page){
//do nothing
}
}
class BasicUserType{
public function userRequestedPage($user, $page){
throw new Exception("You cant access this page");
}
}
class CreditUserType{
public function userRequestedPage($user, $page){
$user->credit--;
$user->save();
}
}
这样，与 userType 相关的所有内容都是分开的，可以轻松添加新类型，而不会破坏现有类型。
顺便说一句：这只不过是普通的旧多态性。策略只是OOP要点的另一个闪亮词，就像大多数模式一样。不要浪费时间思考模式，它们对灵感有好处，但是你会从真正的OOP中获得更多经验，看看smalltalk - http://www.pharo-project.org/home