探讨如何使用SimpleXML函数来加载和解析XML文档

大量SmipleXML函数可用来加载和解析大量XML文档。
--------------------------------------------------------------------------------
1.simpleXML_load_file()函数来加载指定的XML文件到对象。如果加载文件时遇到问题，则返回FLASE。例：
book.xml文件：
代码如下:
<?xml version="1.0" standalone="yes"?>
<library>
 <book>
  <title>Pride and Prejudice</title>
  <author gender="female">Jane Austen</author>
  <description>Jane Austen's most popular work.</description>
 </book>
 <book>
  <title>The Conformist</title>
  <author gender="male">Alberto Moravia</author>
  <description>Alberto Moravia's classic psyhcological novel.</description>
 </book>
 <book>
  <title>The Sun Also Rises</title>
  <author gender="male">Ernest Hemingway</author>
  <description>The masterpiece that launched Hemingway's career.</description>
 </book>
</library>

php文件：
代码如下:
<?php
$xml=simplexml_load_file("book.xml");echo "<pre>";
var_dump($xml);
?>

输出结果：
代码如下:
object(SimpleXMLElement)#1 (1) {
  ["book"]=>
  array(3) {
    [0]=>
    object(SimpleXMLElement)#2 (3) {
      ["title"]=>
      string(19) "Pride and Prejudice"
      ["author"]=>
      string(11) "Jane Austen"
      ["description"]=>
      string(32) "Jane Austen's most popular work."
    }
    [1]=>
    object(SimpleXMLElement)#3 (3) {
      ["title"]=>
      string(14) "The Conformist"
      ["author"]=>
      string(15) "Alberto Moravia"
      ["description"]=>
      string(46) "Alberto Moravia's classic psyhcological novel."
    }
    [2]=>
    object(SimpleXMLElement)#4 (3) {
      ["title"]=>
      string(18) "The Sun Also Rises"
      ["author"]=>
      string(16) "Ernest Hemingway"
      ["description"]=>
      string(49) "The masterpiece that launched Hemingway's career."
    }
  }
}