php中SimpleXML的使用方法，加载XML，解析XML

首先先创建一个XML文件，post.xml，内容如下：

<?xml version="1.0" standalone="yes"?><library>    <book>        <title>hahhah</title>        <author gender="female">Tom Lusten</author>        <description>Jane Austen's most popular work.</description>    </book>    <book>        <title>prindesfjkafg</title>        <author gender="male" age="20">Luck Aun</author>        <description>Jane Austen's most popular work.</description>    </book>    <book>        <title>nihao</title>        <author gender="female">Luck Aun</author>        <description>Jane Austen's most popular work.</description>        <cast>            <character>Jane ma ldfejt.</character>            <character>Jack is a children.</character>            <character>I'm very happy!</character>            <character>Lady Barnes</character>        </cast>    </book></library>

一、加载XML

1.加载xml文件
simplexml_load_file( )将xml文件加载到对象

$xml = simplexml_load_file("post.xml");var_dump($xml);

打印结果如下：

object(SimpleXMLElement)#1 (1) {  ["book"]=>  array(3) {    [0]=>    object(SimpleXMLElement)#2 (3) {      ["title"]=>      string(6) "hahhah"      ["author"]=>      string(10) "Tom Lusten"      ["description"]=>      string(32) "Jane Austen's most popular work."    }    [1]=>    object(SimpleXMLElement)#3 (3) {      ["title"]=>      string(13) "prindesfjkafg"      ["author"]=>      string(8) "Luck Aun"      ["description"]=>      string(32) "Jane Austen's most popular work."    }    [2]=>    object(SimpleXMLElement)#4 (4) {      ["title"]=>      string(5) "nihao"      ["author"]=>      string(8) "Luck Aun"      ["description"]=>      string(32) "Jane Austen's most popular work."      ["cast"]=>      object(SimpleXMLElement)#5 (1) {        ["character"]=>        array(4) {          [0]=>          string(15) "Jane ma ldfejt."          [1]=>          string(19) "Jack is a children."          [2]=>          string(15) "I'm very happy!"          [3]=>          string(11) "Lady Barnes"        }      }    }  }}

2.加载xml字符串
simplexml_load_string( ),作用与simplexml_load_file( )相同，知识输入参数为字符串形式。
3.加载xml DOM文档
simplexml_import_dom( )

二、解析xml

如下方式：
1.返回最初的XML文档，只是删除了换行字符，各个字符也转换为相应的HTML实体

echo htmlspecialchars($xml->asXML());

2.首先更多的了解元素，假设想要知道每位作者的名字

//打印出每一位作者foreach($xml->book as $book) {    printf("%s is %s.<br />",$book->author,$book->author->attributes());}

3.确定某本书作者的属性

 echo $xml->book[0]->author->attributes();//打印某位作者属性

若作者的属性不只一个可用下面的方式：

//对作者属性进行遍历foreach ($xml->book[1]->author->attributes() as $key => $value) {    printf("%s = %s <br />",$key,$value);}

4.children( )函数，了解某个节点中的子节点

//对cast节点中的character进行遍历foreach ($xml->book[2]->cast->children() as $character) {    echo $character."<br />";}

5.xpath获取节点信息

//获取所有作者名$authors = $xml->xpath('/library/book/author');foreach ($authors as $author) {    echo "$author <br />";}

6.xpath有选择的获取节点信息

//获取所有作者名为Luck Aun的书籍的title$books = $xml->xpath("/library/book[author='Luck Aun']");foreach($books as $titles) {    echo $titles->title.'<br />';}

以上2-6种情况结果如下所示：