php中的XML DOM（11）-tutoriel php-php.cn

7.创建节点

在dom操作中，增删改操作必须要找父节点

1、DOMElement DOMDocument::createElement ( string $name [, string $value ] )

创建节点，返回的是一个节点对象

string $name ：节点的名（元素名）

[, string $value ] ：节点的值

2、DOMNode DOMNode::appendChild ( DOMNode $newnode )

追加子节点

DOMNode $newnode：子节点

3、int DOMDocument::save ( string $filename )

将dom中的数据保存到指定的文件中

4、documentElement属性，表示dom模型中的根节点

<span>php
    header ( </span><span>'</span><span>Content-Type:text/html;charset=gb2312</span><span>'</span><span> );
    $dom </span>= <span>new</span> DOMDocument ( <span>'</span><span>1.0</span><span>'</span>, <span>'</span><span>utf-8</span><span>'</span><span> );
    $dom</span>->load ( <span>'</span><span>demo01.xml</span><span>'</span><span> );
</span><span>//</span><span> 创建节点仅仅是表示在内存中创建出这个节点对象，但这个对象和我们之前的
</span><span>//</span><span> dom模型没有任何联系</span>
    $person = $dom->createElement ( <span>'</span><span>person</span><span>'</span><span> );
    $name </span>= $dom->createElement ( <span>'</span><span>name</span><span>'</span>, <span>'</span><span>huangliu</span><span>'</span><span> );
    $age </span>= $dom->createElement ( <span>'</span><span>age</span><span>'</span>, <span>'</span><span>18</span><span>'</span><span> );
</span><span>//</span><span> 将name和age做为子节点追加至person节点</span>
    $person-><span>appendChild ( $name );
    $person</span>-><span>appendChild ( $age );
</span><span>//</span><span> $dom->getElementsByTagName('persons')->item(0)->appendChild($newnode)
</span><span>//</span><span> 将person做了子节点追加至根节点</span>
    $dom->documentElement-><span>appendChild ( $person );
</span><span>//</span><span> 将dom中的所有数据重新保存到demo01.xml文件中</span>
    $dom->save ( <span>'</span><span>demo01.xml</span><span>'</span> );

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结果：

<person>
        <name>huangliu</name>
        <age><span>18</span></age>
    </person>

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8、删除节点

DOMNode DOMNode::removeChild ( DOMNode $oldnode )

DOMNode $oldnode：要被删除的节点对象

示例：把以下蓝色部分给删除掉

<span>php
    header ( </span><span>'</span><span>Content-Type:text/html;charset=gb2312</span><span>'</span><span> );
    $dom </span>= <span>new</span> DOMDocument ( <span>'</span><span>1.0</span><span>'</span>, <span>'</span><span>utf-8</span><span>'</span><span> );
    $dom</span>->load ( <span>'</span><span>demo01.xml</span><span>'</span><span> );
</span><span>//</span><span> 首先找到要删除的节点对象</span>
    $person = $dom->getElementsByTagName ( <span>'</span><span>person</span><span>'</span> )->item ( <span>1</span><span> );
</span><span>//</span><span> 将节点删除</span>
    $dom->documentElement-><span>removeChild ( $person );
</span><span>//</span><span> 重新保存文件</span>
    $dom->save ( <span>'</span><span>demo01.xml</span><span>'</span> );

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9、修改节点

DOMNode DOMNode::replaceChild ( DOMNode $newnode , DOMNode $oldnode )

DOMNode $newnode ：新节点

DOMNode $oldnode ：原节点

<span>php
    header ( </span><span>'</span><span>Content-Type:text/html;charset=gb2312</span><span>'</span><span> );
    $dom </span>= <span>new</span> DOMDocument ( <span>'</span><span>1.0</span><span>'</span>, <span>'</span><span>utf-8</span><span>'</span><span> );
    $dom</span>->load ( <span>'</span><span>demo01.xml</span><span>'</span><span> );
</span><span>//</span><span> 找到要被替换掉的节点</span>
    $oldNode = $dom->getElementsByTagName ( <span>'</span><span>person</span><span>'</span> )->item ( <span>2</span><span> );
</span><span>//</span><span> 创建出新的节点</span>
    $person = $dom->createElement ( <span>'</span><span>person</span><span>'</span><span> );
    $name </span>= $dom->createElement ( <span>'</span><span>name</span><span>'</span>, <span>'</span><span>songjiang</span><span>'</span><span> );
    $age </span>= $dom->createElement ( <span>'</span><span>age</span><span>'</span>, <span>100</span><span> );
    $person</span>-><span>appendChild ( $name );
    $person</span>-><span>appendChild ( $age );
</span><span>//</span><span> 用新节点替换原节点</span>
    $dom->documentElement-><span>replaceChild ( $person, $oldNode );
</span><span>//</span><span> 保存文件</span>
    $dom->save ( <span>'</span><span>demo01.xml</span><span>'</span> );

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10、保存

? string DOMDocument::saveXML

将dom中的数据保存至一个字符串变量中

? int DOMDocument::save ( string $filename )

将dom中的数据保存到指定的文件中

11、关于属性的增删改

1、DOMAttr DOMElement::setAttribute( string $name , string $value )

添加属性

string $name ：属性名

string $value ：属性值

为person添加id='s102'这个属性

<span>php
    header ( </span><span>'</span><span>Content-Type:text/html;charset=gb2312</span><span>'</span><span> );
    $dom </span>= <span>new</span> DOMDocument ( <span>'</span><span>1.0</span><span>'</span>, <span>'</span><span>utf-8</span><span>'</span><span> );
    $dom</span>->load ( <span>'</span><span>demo01.xml</span><span>'</span><span> );
</span><span>//</span><span> 为第二个人添加id属性
</span><span>//</span><span> 找到第二个人</span>
    $person = $dom->getElementsByTagName ( <span>'</span><span>person</span><span>'</span> )->item ( <span>1</span><span> );
</span><span>//</span><span> 添加id属性</span>
    $person->setAttribute ( <span>'</span><span>id</span><span>'</span>, <span>'</span><span>s102</span><span>'</span><span> );
</span><span>//</span><span> 保存文件</span>
    $dom->save ( <span>'</span><span>demo01.xml</span><span>'</span> );

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2、 DOMAttr DOMElement::setAttribute( string $name , string $value )

修改属性

string $name ：属性名

string $value ：属性值

如果一个节点没有此属性，表示添加属性（注意与上面的区别）

如果一个节点已经存在这个属性，表示修改属性

3、bool DOMElement::removeAttribute ( string $name )

删除属性（不是删除节点）

$name：要被删除的属性

<span>php
    header ( </span><span>'</span><span>Content-Type:text/html;charset=gb2312</span><span>'</span><span> );
    $dom </span>= <span>new</span> DOMDocument ( <span>'</span><span>1.0</span><span>'</span>, <span>'</span><span>utf-8</span><span>'</span><span> );
    $dom</span>->load ( <span>'</span><span>demo01.xml</span><span>'</span><span> );
</span><span>//</span><span> 删除第2个人的id属性
</span><span>//</span><span> 找到第二个人</span>
    $person = $dom->getElementsByTagName ( <span>'</span><span>person</span><span>'</span> )->item ( <span>1</span><span> );
</span><span>//</span><span> 删除id属性</span>
    $person->removeAttribute(<span>'</span><span>id</span><span>'</span><span>);
</span><span>//</span><span> 保存文件</span>
    $dom->save ( <span>'</span><span>demo01.xml</span><span>'</span> );

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4、获取属性

string DOMElement::getAttribute ( string $name )

string $name：属性名

<span>php
    header ( </span><span>'</span><span>Content-Type:text/html;charset=gb2312</span><span>'</span><span> );
    $dom </span>= <span>new</span> DOMDocument ( <span>'</span><span>1.0</span><span>'</span>, <span>'</span><span>utf-8</span><span>'</span><span> );
    $dom</span>->load ( <span>'</span><span>demo01.xml</span><span>'</span><span> );
</span><span>//</span><span> 查询第1个人的id属性
</span><span>//</span><span> 找到第1个人</span>
    $person = $dom->getElementsByTagName ( <span>'</span><span>person</span><span>'</span> )->item ( <span>0</span><span> );
</span><span>//</span><span> 查询id属性</span>
    echo $person->getAttribute(<span>'</span><span>id</span><span>'</span>);

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12 SimpleXML

PHP DOM：增删改

SimpleXML：查询

一、读取xml

1、 simpleXMLElement simplexml_load_file ( string $filename)

从某个xml文件中读取数据

string $filename：xml文件名

2、SimpleXMLElement::__construct ( string data)

从某个字符串中读取数据

String data：xml格式的字符串

如果数据保存到文件中，使用simplexml_load_file读取