SimpleXML processing in PHP_PHP tutorial

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Jul 13, 2016 pm 05:33 PM

phpsimplexmlmainstreamlearnanddeal withdevelopVersionnowoflanguage

　　了解和 php(做为现在的主流开发语言) 版本 5 捆绑到一起的 Simplexml(标准化越来越近了) 扩展，它使 php(做为现在的主流开发语言) 页面能够以 php(做为现在的主流开发语言) 友好的语法来查询、搜索、修改和重新发布 xml(标准化越来越近了)。

　　php(做为现在的主流开发语言) 版本 5 引入了 Simplexml(标准化越来越近了)，一种用于读写 xml(标准化越来越近了) 的新的应用程序编程接口(API)。在 Simplexml(标准化越来越近了) 中，下面的这样的表达式:

　　$doc->rss->channel->item->title

　　从文档中选择元素。只要熟悉文档的结构，很容易编写这种表达式。但是，如果不很清楚需要的元素出现在何处(比如 Docbook、HTML 和类似的叙述性文档中)，Simplexml(标准化越来越近了) 可以使用 XPath 表达式寻找这些元素。

　　开始使用 Simplexml(标准化越来越近了)

　　假设需要一个 php(做为现在的主流开发语言) 页面将 RSS 提要(feed)转化成 HTML。RSS 是一种简单的 xml(标准化越来越近了) 格式用于发布连锁内容。文档的根元素是 rss，它包括一个 channel 元素。channel 元素包含关于提要的元数据，如标题、语言和 URL。它还包含各种封装在 item 元素中的报道。每个 item 都有一个 link 元素，包括一个 URL，还有 title 或 description(通常两者都有)，包含普通文本。不使用名称空间。RSS 的内容当然不止这些，不过对本文来说知道这些就足够了。清单 1 显示了一个典型的例子，它包含两个新闻项。

　　清单 1. RSS 提要

(标准化越来越近了) version="1.0" encoding="UTF-8"?>

Mokka mit Schlag
http://www.elharo.com/blog
en

    Penn Station: Gone but not Forgotten

     The old Penn Station in New York was torn down before I was born.
     Looking at these pictures, that feels like a mistake. The current site is
     functional, but no more; really just some office towers and underground
     corridors of no particular interest or beauty. The new Madison Square...

    http://www.elharo.com/blog/new-york/2006/07/31/penn-station

    Personal for Elliotte Harold
    Some people use very obnoxious spam filters that require you
     to type some random string in your subject such as E37T to get through.
     Needless to say neither I nor most other people bother to communicate with
     these paranoids. They are grossly overreacting to the spam problem.
     Personally I wont ...

http://www.elharo.com/blog/tech/2006/07/28/personal-for-elliotte-harold/

　　我们来开发一个 php(做为现在的主流开发语言) 页面将 RSS 提要格式化为 HTML。清单 2 显示了这个页面的基本结构。

　　清单 2. php(做为现在的主流开发语言) 代码的静态结构

(做为现在的主流开发语言) // Load and parse the xml(标准化越来越近了) document ?>
(标准化越来越近了):lang="en" lang="en">

<?php <font class=reblank>(做为现在的主流开发语言) // The title will be read from the RSS ?>

(as the current mainstream development language) // The title will be read from the RSS again ?>

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