我在通過包含的文件在類之間調(diào)用靜態(tài)變量/方法時(shí)遇到問題。這是代碼示例：<?phpclass Router{ static $instance; public static function GetInstance() { if(self::$instance == null) self::$instance = new self; return self::$instance; } function __construct() { include 'test2.php'; /* test2.php CONTENTS */ /* Routes::doSomething(); */ } public function doSomthing() { echo 1; }}class Routes{ // test.php script will call this function // this function will try to get Router static instance to call a dynamic function // keep in mind that the static instance of Router was already created // some how test2.php script will not be able to read the static instance and will create another one // and that will cause the page keep including and running the same script over and over and idk why public static function doSomething() { Router::GetInstance()->doSomthing(); }}$router = Router::GetInstance();其中 test2.php 中的腳本Routes::doSomething();將無法讀取 Router 類中的靜態(tài) $instance。我無法弄清楚問題是什么，并嘗試查看包含腳本是否會(huì)導(dǎo)致此類問題，但我什至不知道應(yīng)該尋找什么。請(qǐng)幫忙，謝謝。
1 回答
呼啦一陣風(fēng)
TA貢獻(xiàn)1802條經(jīng)驗(yàn) 獲得超6個(gè)贊
經(jīng)過一些測(cè)試發(fā)現(xiàn) PHP 無法處理此類腳本。因?yàn)槁暶髯兞康倪^程以及PHP如何處理它。
我無法提供任何來源來支持我要說的內(nèi)容，這只是我迄今為止從測(cè)試中了解到的內(nèi)容。但我會(huì)嘗試用我較低的英語水平來解釋它，希望以后能對(duì)某人有所幫助。
因此，在 PHP 中，當(dāng)您嘗試使用類對(duì)象聲明靜態(tài)/動(dòng)態(tài)變量時(shí)，如下所示：
self::$Instance = new TestClass;
PHP 將按步驟處理命令，以這種方式工作：
步驟1 ：Declare self::$Instance as null
第2步 ：Create temporary_object from TestClass class
步驟#3：Run __construct method in temporary_object then wait until its done
步驟4 ：Set self::$Instance as temporary_object which is instanceof TestClass
我的代碼中存在問題，您可以看到我試圖在__construct方法中包含.php 文件。包含的文件將運(yùn)行一個(gè)靜態(tài)函數(shù)，該函數(shù)將嘗試讀取Router類中的 self::$instance 。雖然static::$Instance未設(shè)置并且仍然等于null，因?yàn)開_construct尚未完成。
所以基本上不要嘗試在 __construct 方法中讀取同一類的靜態(tài)實(shí)例。
這里的腳本應(yīng)該是這樣的，因?yàn)槲业慕忉尣磺宄?/p>
<?php
class Router
{
static $instance;
public static function GetInstance()
{
if(self::$instance == null)
self::$instance = new self;
return self::$instance;
}
function __construct()
{
}
public function LoadFiles(){
include 'test2.php';
/* test2.php CONTENTS */
/* Routes::doSomething(); */
}
public function doSomthing()
{
echo 1;
}
}
class Routes
{
// test.php script will call this function
// this function will try to get Router static instance to call a dynamic function
// keep in mind that the static instance of Router was already created
// some how test2.php script will not be able to read the static instance and will create another one
// and that will cause the page keep including and running the same script over and over and idk why
public static function doSomething()
{
Router::GetInstance()->doSomthing();
}
}
$router = Router::GetInstance();
$router->LoadFiles();
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