我有一个特征正在使用另一个特征,现在我收到关于类中不存在的函数的错误。 我简化了代码:
设置.php:
<?php
trait settings{
protected function getSetting($type, $setting){ // read setting from config.ini
try{
$configFile=dirname(__FILE__)."/../config.ini";
if(!file_exists($configFile)||!is_file($configFile))throw new Exception("Config file was not found. ");
$configContents=parse_ini_file($configFile,true);
if(is_array($configContents)&&array_key_exists($type,$configContents)&&is_array($configContents[$type])&&array_key_exists($setting,$configContents[$type]))return $configContents[$type][$setting];
else throw new Exception("Setting ".$setting." could not be found in ".$type.".");
}
catch(Exception $e){throw new Exception($e->getMessage());}
}
}
?>
数据库.php
<?php
trait database{
use settings,session;
private $pdo;
protected function connect(){ // connect to database
try{
$this->pdo=new PDO("mysql:host=".$this->getSetting("db","host").";dbname=".$this->getSetting("db","database"),$this->getSetting("db","user"),$this->getSetting("db","password"));
$this->init();
}
catch(PDOException $e){throw new Exception($e->getMessage());}
}
}
?>
用户.php
<?php
class users{
use database;
public function __construct(){
try{
$this->connect();
}
catch(Exception $e){throw new Exception($e->getMessage());}
}
public function __destruct(){
unset($this);
}
public function isAdmin(){
try{
if($this->loginStatus()===true){
}
else return false;
}
catch(Exception $e){throw new Exception($e->getMessage());}
}
public function loginStatus(){
if(!$this->getSession("tysus")||!$this->getSession("tyspw"))return false;// user is not logged in because we couldn't find session with username and/or password
if(!$this->userExists($this->getSession("tysus"),$this->getSession("tyspw")))return false;// user is unknown to database
return true;// other checks failed, user must be logged in
}
}
?>
现在我收到这个错误:
Fatal error: Call to undefined method users::readSetting() in /home/deb2371/domains/nonamenohistory.com/public_html/include/classes/class.database.php on line 18
我认为会发生这样的事情: 类用户使用特征数据库,特征数据库将使用特征设置和特征 session 。
如果是这样,我就不会收到任何错误,但不幸的是,事实并非如此。
有人知道如何解决这个问题吗?
最佳答案
Code reuse is one of the most important aspects of object-oriented programming.
Multiple Traits
和Composing Multiple Traits
的简单示例,您可以通过它轻松分析您的情况。
- 使用多个特征
一个类可以使用多个特征。以下示例演示如何在 IDE 类中使用多个特征。为了演示,它模拟了PHP中的C编译模型。
<?php
trait Preprocessor{
function preprocess() {
echo 'Preprocess...done'. '<br/>';
}
}
trait Compiler{
function compile() {
echo 'Compile code... done'. '<br/>';
}
}
trait Assembler{
function createObjCode() {
echo 'Create the object code files... done.' . '<br/>';
}
}
trait Linker{
function createExec(){
echo 'Create the executable file...done' . '<br/>';
}
}
class IDE{
use Preprocessor, Compiler, Assembler, Linker;
function run() {
$this->preprocess();
$this->compile();
$this->createObjCode();
$this->createExec();
echo 'Execute the file...done' . '<br/>';
}
}
$ide = new IDE();
$ide->run();
- 组合多个特征
通过在特征声明中使用 use 语句,特征可以由其他特征组成。请参阅以下示例:
<?php
trait Reader{
public function read($source){
echo sprintf("Read from %s <br/>",$source);
}
}
trait Writer{
public function write($destination){
echo sprintf("Write to %s <br/>",$destination);
}
}
trait Copier{
use Reader, Writer;
public function copy($source,$destination){
$this->read($source);
$this->write($destination);
}
}
class FileUtil{
use Copier;
public function copyFile($source,$destination){
$this->copy($source, $destination);
}
}
关于php trait 使用另一个 trait,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/20745907/