messages.xml
========================================================
<?xml version="1.0" ?>
<!--Sample XML document -->
<SystemMessage>
<MessageTitle>System Down for Maintenance</MessageTitle>
<MessageBody>Going down for maintenance soon!</MessageBody>
<MessageAuthor>
<MessageAuthorName>Joe SystemGod</MessageAuthorName>
<MessageAuthorEmail>systemgod@someserver.com
</MessageAuthorEmail>
</MessageAuthor>
<MessageDate>March 4, 2004</MessageDate>
<MessageNumber>10</MessageNumber>
</SystemMessage>
========================================================
xml 是一种创建元数据的语言,元数据是描述其它数据的数据,PHP中的XML处理是基于LIBXML2的，安装时默认开启。
可以通过phpinfo()函数查看是否开启了XML处理模块,DOM,LIBXML,SAMPLEXML。
首先,通过samplexml_load_file函数把xml文件加载到一个对象中,samplexml_load_file可以用户远程文件.
例如:
$xml = samplexml_load_file("messages.xml"); // 本地文件系统,当前目录
$xml = samplexml_load_file("http://www.xml.org.cn/messages.xml"); // 远程web服务器
用 var_dump($xml) 和 print_r($xml) 分别输出其结构.var_dump给出了变量的类型和长度,而print_r可读性更强
输出对象中的所有元素名称和它的值.
echo $xml->MessageTitle;//输出消息的标题
echo $xml->MessageBody; // 输出消息体
echo $xml->MessageAuthor;//消息的作者
echo $xml->MessageDate;// 消息产生的日期
echo $xml->MessageNumber;// 消息代码
===================================================
另外,还有一个函数,可以把XML字符串加载到一个simplexml对象中取
$channel =<<<_XML_
<channel>
<title>What's For Dinner</title>
<link>http://menu.example.com/</link>
<description>These are your choices of what to eat tonight. </description>
</channel>
_XML_;
$xml = simplexml_load_string($channel);
===================================================
rss.xml
=============================================
<?xml version="1.0" encoding="utf-8"?>
<rss version="0.91">
<channel>
<title>What's For Dinner</title>
<link>http://menu.example.com/</link>
<description>These are your choices of what to eat tonight.</description>
<item>
<title>
Braised Sea Cucumber</title>
<link>http://menu.example.com/dishes.php?dish=cuke</link>
<description>Gentle flavors of the sea that nourish and refresh you. </description>
</item>
<item>
<title>Baked Giblets with Salt</title>
<link>http://menu.example.com/dishes.php?dish=giblets</link>
<description>Rich giblet flavor infused with salt and spice. </description>
</item>
<item>
<title>Abalone with Marrow and Duck Feet</title>
<link>http://menu.example.com/dishes.php?dish=abalone</link>
<description>There's no mistaking the special pleasure of abalone. </description>
</item>
</channel>
</rss>
=====================================================
1.访问具有相同元素名称的节点
2.通过foreach循环所有相同元素名称的子节点
foreach($xml->channel->item as $key=>$value)
{
print "Title: " . $item->title . "\n";
}
3.输出整个文档
echo $xml->asXML();
4.把节点作为字符串输出
echo $xml->channel->item[0]->asXML();
这将输出文本
<item>
<title>
Braised Sea Cucumber</title>
<link>http://menu.example.com/dishes.php?dish=cuke</link>
<description>Gentle flavors of the sea that nourish and refresh you. </description>
</item>
带文件名参数的asXML将会把原本输出的内容保存为一个文件
$xml->channel->item[0]->asXML("item[0].xml");
完整的代码:
rss.xml
=====
<?xml version="1.0" encoding="utf-8"?>
<rss version="0.91">
<channel>
<title>What's For Dinner</title>
<link>http://menu.example.com/</link>
<description>These are your choices of what to eat tonight.</description>
<item>
<title>
Braised Sea Cucumber</title>
<link>http://menu.example.com/dishes.php?dish=cuke</link>
<description>Gentle flavors of the sea that nourish and refresh you. </description>
</item>
<item>
<title>Baked Giblets with Salt</title>
<link>http://menu.example.com/dishes.php?dish=giblets</link>
<description>Rich giblet flavor infused with salt and spice. </description>
</item>
<item>
<title>Abalone with Marrow and Duck Feet</title>
<link>http://menu.example.com/dishes.php?dish=abalone</link>
<description>There's no mistaking the special pleasure of abalone. </description>
</item>
</channel>
</rss>
rss.php
======
<?php
$xml = simplexml_load_file("rss.xml");
echo "<h3>".$xml->channel->title."</h3><br>";
echo "<ul>";
echo "<li>Title:".$xml->channel->item[0]->title."</li>";
echo "<li>Title:".$xml->channel->item[1]->title."</li>";
