XML DOM in php (10)

1.PHP DOM (1)

The DOM in Php is different from javascript. There is no need to add another node for attributes

2.Main categories

DOMDocument: Document class

DOMNodeList: node list class

DOMNode: node class

DOMElement: element class

3. DOMDocument class

3.1 Create document object

DOMDocument::__construct ([ string $version [, string $encoding ]] )

 [ string $version: version number

 [, string $encoding ]]: Character set

3.2. Load xml file

       mixed DOMDocument::load (string $filename)

String $filename: The name of the xml file to be loaded

3.3. Obtain nodes

DOMNodeList DOMDocument::getElementsByTagName (string name)

String name: The node name to be obtained

Example: Demo.php

<?<span>php
    header ( </span><span>'</span><span>Content-Type:text/html;charset=gb2312</span><span>'</span><span> );
</span><span>//</span><span> 利用php解析demo01.xml
</span><span>//</span><span> 实例化dom对象</span>
    $dom = <span>new</span><span> DOMDocument ();
</span><span>//</span><span> 加载xml文件</span>
    $dom->load ( <span>'</span><span>demo01.xml</span><span>'</span><span> );
</span><span>//</span><span> 通过dom对象获取person节点，注意：这里返回值是一个DOMNodeList类对象</span>
    $persons = $dom->getElementsByTagName ( <span>'</span><span>person</span><span>'</span><span> );
</span><span>//</span><span> 共有几个person</span>
    echo <span>'</span><span>共有</span><span>'</span> . $persons->length . <span>'</span><span>个人<br></span><span>'</span>;      <span>//</span><span>输出共有两个人
</span><span>//</span><span> 选中索引为0的person，也就是第一个人</span>
    $person = $persons->item ( <span>0</span><span> );
</span><span>//</span><span> 在这个person下获取name节点，返回的仍然是一个DOMNodeList类对象</span>
    $names = $person->getElementsByTagName ( <span>'</span><span>name</span><span>'</span><span> );    
</span><span>//</span><span> 输出姓名</span>
echo $names->item ( <span>0</span> )->nodeValue . <span>'</span><span><br></span><span>'</span>;       <span>//</span><span>输出'张三'</span>
为什么要进行两次取的Nodelist呢？请参照上图，因为有两个节点

demo.xml

<?xml version=<span>"</span><span>1.0</span><span>"</span> encoding=<span>"</span><span>UTF-8</span><span>"</span>?>
<persons>
    <person id=<span>"</span><span>s101</span><span>"</span>>
        <name>zhangsan</name>
        <age><span>30</span></age>
    </person>
    <person>
        <name>wangwu</name>
        <age><span>18</span></age>
    </person>
</persons>

4. DOMNodeList class (the person above is the NodeList node)

1. Length

How many nodes are there in the current node list

2. DOMElement DOMNodelist::item (int $index)

 Select the node with index

int $index：index

5. DOMNode class

1. nodeValue The value of the node

6. About reading attributes

1. bool DOMElement::hasAttribute (string $name)

Determine whether it has a certain attribute (only judge whether there is a certain attribute)

String $name: attribute name

2. bool DOMNode::hasAttributes (void)

Determine whether it has attributes (return true as long as there are attributes)

3. string DOMElement::getAttribute ( string $name )

Get the attribute value of the specified attribute

String $name: attribute name

Example 2. Output using coherent operations

<?<span>php
    $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> 想得到第一个人的姓名</span>
    echo $dom->getElementsByTagName ( <span>'</span><span>person</span><span>'</span> )->item ( <span>0</span><span> )
    </span>->getElementsByTagName ( <span>'</span><span>name</span><span>'</span> )->item ( <span>0</span> )-><span>nodeValue;
输出：张三</span>

Example3:

<?<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> );
    $person </span>= $dom->getElementsByTagName ( <span>'</span><span>person</span><span>'</span> )->item ( <span>0</span><span> );
</span><span>//</span><span> 判断节点是否具有id属性</span>
    <span>if</span> ($person->hasAttribute ( <span>'</span><span>id</span><span>'</span><span> )) {
        echo </span><span>'</span><span>具有id属性</span><span>'</span><span>;
    } </span><span>else</span><span> {
        echo </span><span>'</span><span>没有id属性</span><span>'</span><span>;
    }
    echo </span><span>'</span><span><br></span><span>'</span><span>;
</span><span>//</span><span> 判断节点是否具有属性</span>
    <span>if</span> ($person-><span>hasAttributes ()) {
        echo </span><span>'</span><span>有属性</span><span>'</span><span>;
    } </span><span>else</span><span> {
        echo </span><span>'</span><span>没有任何属性</span><span>'</span><span>;
    }
    echo </span><span>'</span><span><br></span><span>'</span><span>;
</span><span>//</span><span> 得到第一个person的id属性值</span>
    echo $person->getAttribute ( <span>'</span><span>id</span><span>'</span> );

The previous example could only get one piece of data. Now I want to get complete information about everyone. How to achieve this?

Example 4:

What if things like that have attributes also need to be traversed?

<?<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> 得到所有person节点</span>
    $persons = $dom->getElementsByTagName ( <span>'</span><span>person</span><span>'</span><span> );
</span><span>//</span><span> 得到总人数</span>
    $count = $persons-><span>length;
    </span><span>for</span>($i = <span>0</span>; $i < $count; $i ++<span>) {
    </span><span>//</span><span> $person表示第i个人</span>
        $person = $persons-><span>item ( $i );
        echo </span><span>'</span><span>第</span><span>'</span> . ($i + <span>1</span>) . <span>'</span><span>个人的</span><span>'</span><span>;
        </span><span>if</span> ($person->hasAttribute ( <span>'</span><span>id</span><span>'</span><span> )) {
            echo </span><span>'</span><span>学号：</span><span>'</span> . $person->getAttribute ( <span>'</span><span>id</span><span>'</span><span> );
        }
        echo </span><span>'</span><span>姓名：</span><span>'</span> . $person->getElementsByTagName ( <span>'</span><span>name</span><span>'</span> )->item ( <span>0</span> )-><span>nodeValue;
        echo </span><span>'</span><span>年龄：</span><span>'</span> . $person->getElementsByTagName ( <span>'</span><span>age</span><span>'</span> )->item ( <span>0</span> )-><span>nodeValue;
        echo </span><span>'</span><span><br></span><span>'</span><span>;
    }
</span>?>

The above introduces the XML DOM (10) in PHP, including the relevant content. I hope it will be helpful to friends who are interested in PHP tutorials.