PHP:SimpleXMLElement() 类和 SimpleXML_load_string() 之间有什么区别? [英] PHP: Whats's the difference between the SimpleXMLElement() class and SimpleXML_load_string()?

问题描述

我见过很多编码人员实现了 SimpleXML_load_string() 而不是 SimpleXMLElement() 类.使用前者比使用后者有什么好处吗?我已经阅读了 关于 simplexml 的 PHP 手册.我无法理解它是什么.

I've seen alot of coders implement SimpleXML_load_string() instead of the SimpleXMLElement() class. Are there any benefits to using the former over the latter? I've read the PHP manual on simplexml. I couldn't manage to get a grasp on what it is.

任何帮助和指导(可能通过示例)将不胜感激.提前致谢.

Any help and guidance (perhaps through examples) would be much appreciated. Thanks in advance.

推荐答案

simplexml_load_string()(顾名思义)从字符串中加载 xml 并返回 SimepleXMLElement.这与仅使用类的常用构造函数没有区别.

simplexml_load_string() (as the name suggest) load xml from a string and returns an object of SimepleXMLElement. There is no difference between this and using just the usual constructor of the class.

更新:

SimpleXML::__construct() 有一个附加参数(第三个)bool $data_is_url = false.如果这是 true，则行为与 simplexml_load_file() 相同(与通用流包装器结合使用).因此，两个 simplexml_load_*() 函数都涵盖了与 SimpleXML::__construct() 相同的功能.

SimpleXML::__construct() has an additional parameter (the third one) bool $data_is_url = false. If this is true the behavior is the same as simplexml_load_file() (in conjunction with the common stream wrappers). Thus both simplexml_load_*()-functions cover the same functionality as SimpleXML::__construct().

另外的函数 simplexml_load_*() 有第二个参数 string $class_name = "SimpleXMLElement" 来指定要返回的对象的类.这不是函数的特定功能，因为您也可以使用"与通常的实例化非常相似的东西

Additional the functions simplexml_load_*() has a second parameter string $class_name = "SimpleXMLElement" to specify the class of the object to get returned. Thats not a specific feature of the functions, because you can "use" something very similar with usual instanciation too

class MyXML extends SimpleXMLElement {}
$a = new MyXML($xml);
$b = simplexml_load_string($xml, 'MyXML');

OOP 方法和过程方法之间的区别在于，函数在出错时返回 false，但构造函数会抛出异常.

A difference between the OOP- and the procedural approach is, that the functions return false on error, but the constructor throws an Exception.

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