扩展在PHP中实现接口的类时找不到该类 [英] class not found when extending class that implements interface in PHP

问题描述

<?php

class A extends B {}

class B implements C {}

interface C {}

上面的代码抛出致命错误:找不到类'B'" ... 这是一个PHP错误?还是?

环境:带有Suhosin-Patch(cli)的PHP 5.3.6-13ubuntu3.2(内置:2011年10月13日23:19:13) 版权所有(c)1997-2011 The PHP Group Zend Engine v2.3.0，版权所有(c)1998-2011 Zend Technologies 与Xdebug v2.1.0，版权所有(c)2002-2010，作者Derick Rethans "

解决方案

您在类定义的顺序上遇到了麻烦.只要在同一文件中定义了接口，就可以在任何地方声明它-但是必须在扩展类之前定义类.

以下是在PHP中完全有效的命令:

class B implements C { ... }
class A extends B { ... }
interface C { ... }

一个封闭的错误，要求在PHP5文档中进行澄清./p>

一个类似问题的答案( PHP中的类定义问题?)提到自动加载.如果您使用多个文件，则可能需要调查一下.

<?php

class A extends B {}

class B implements C {}

interface C {}

the code above throws "Fatal error: Class 'B' not found"... Is it a php bug? Or?

Environment: "PHP 5.3.6-13ubuntu3.2 with Suhosin-Patch (cli) (built: Oct 13 2011 23:19:13) Copyright (c) 1997-2011 The PHP Group Zend Engine v2.3.0, Copyright (c) 1998-2011 Zend Technologies with Xdebug v2.1.0, Copyright (c) 2002-2010, by Derick Rethans "

解决方案

You have trouble specifically with the order of your class definitions. As long as the interface is defined in the same file, it can be declared anywhere - but classes must be defined before they can be extended.

The following is perfectly valid order in PHP:

class B implements C { ... }
class A extends B { ... }
interface C { ... }

There is a closed bug requesting clarification in the PHP5 docs.

An answer to a similar question (Does the order of class definition matter in PHP?) mentions Autoloading. You may want to look into this if you're using multiple files.

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