How PHP encapsulates XML

This article mainly introduces how PHP encapsulates XML, and combines it with a complete example to analyze the encapsulation and usage of PHP's related operating techniques for loading, reading and writing xml files. Friends in need can refer to the following

The details are as follows:

xml_dom.php encapsulation class file:

dbfile = $db_file;
    if(!file_exists($db_file))
    {
//     die('未找到数据库文件');
      $this->dblink = new DOMDocument('1.0', 'utf-8');
      $root = $this->dblink->createElement('root');
      $this->dblink->appendChild($root);
      $this->dblink->formatOutput = true;  // xml文件保留缩进样式
      $this->dblink->save($this->dbfile);
    }
    else
    {
      $this->dblink = new DOMDocument();
      $this->dblink->formatOutput = true;
      $this->dblink->load($this->dbfile);
    }
  }
  /**
   * 遍历所有元素
   * ===============================================
   * 标准xml文件，一个元素可能有n个属性，可用自定义键[nodevalue]获取元素值
   * 
   * 
   *   1
   *   标题一
   *   详细内容一
   * 
   * ===============================================
   * 简单xml文件，没有属性，键值一一对应
   * 
   * 
   *   
   *     1
   *     
   *     详细内容一
   *   
   * 
   * @param $node
   * @return array
   */
  function getData($node=0){
    if(!$node)
    {
      $node = $this->dblink->documentElement;
    }
    $array = array();
    foreach($node->attributes as $attribute)
    {
      $key = $attribute->nodeName;
      $val = $attribute->nodeValue;
      $array[$key] = $val;
    }
    if(count($array))  // 有属性，则用[nodevalue]键代表值
    {
      $array['nodevalue'] = $node->nodeValue;
    }
    // 递归遍历所有子元素
    $node_child = $node->firstChild;
    while($node_child)
    {
      if(XML_ELEMENT_NODE == $node_child->nodeType)
      {
        $tagname = $node_child->tagName;
        $result = $this->getData($node_child);
        if(isset($array[$tagname])) // 发现有重复tagName的子元素存在，所以改用数组存储重复tagName的所有子元素
        {
          if(!is_array($array[$tagname][0]))
          {
            $tmp = $array[$tagname];
            $array[$tagname] = array();
            $array[$tagname][] = $tmp;
          }
          $array[$tagname][] = $result;
        }
        else
        {
          $array[$tagname] = $result;
        }
      }
      $node_child = $node_child->nextSibling;
    }
    if(!count($array)) // 没有子元素&没有属性=最末子元素，就返回该元素的nodeValue值
    {
      return $node->nodeValue;
    }
    return $array;
  }
  /**
   * 把array数据写到xml文件（覆盖）
   * @param $data
   */
  public function setData($data,&$node=0)
  {
    $is_root = false;
    if(!$node)
    {
      $is_root = true;
      $node = $this->dblink->documentElement;
      // 清除原数据
      $remove = array();
      $node_child = $node->firstChild;
      while($node_child)
      {
        $remove[] = $node_child;
        $node_child = $node_child->nextSibling;
      }
      foreach($remove as $r)
      {
        $node->removeChild($r);
      }
    }
    if(is_array($data))
    {
      foreach($data as $k=>$v)
      {
        if(is_array($v))
        {
          foreach($v as $r)
          {
            $item = $this->dblink->createElement($k);
            $result = $this->setData($r,$item);
            $node->appendChild($result);
          }
        }
        else
        {
          $item = $this->dblink->createElement($k);
          $value = $this->dblink->createTextNode($v);
          $item->appendChild($value);
          $node->appendChild($item);
        }
      }
    }
    else
    {
      $item = $this->dblink->createTextNode($data);
      $node->appendChild($item);
    }
    if($is_root)
    {
      $this->dblink->save($this->dbfile);  // 覆盖写入
    }
    else
    {
      return $node;
    }
  }
}

A simple usage example is as follows:

smp.xml file:

   
     1
     
     详细内容一
   
   
     2
     
     详细内容二
   
   
     3
     
     详细内容三
   

index.php file:

include("xml_dom.php");
$xml=new xml_dom("smp.xml");//载入xml文件
$xmlarr=$xml->getData();//读取xml文件内容
var_dump($xmlarr);

Run Result:

array(1) {
 ["posts"]=>
 array(3) {
  [0]=>
  array(3) {
   ["id"]=>
   string(1) "1"
   ["title"]=>
   string(9) "标题一"
   ["content"]=>
   string(15) "详细内容一"
  }
  [1]=>
  array(3) {
   ["id"]=>
   string(1) "2"
   ["title"]=>
   string(9) "标题二"
   ["content"]=>
   string(15) "详细内容二"
  }
  [2]=>
  array(3) {
   ["id"]=>
   string(1) "3"
   ["title"]=>
   string(9) "标题三"
   ["content"]=>
   string(15) "详细内容三"
  }
 }
}

Related recommendations:

Detailed explanation of PHP implementation of parsing xml into array case

jQuery traversal of XML nodes and attributes implementation steps

Explanation of examples of XML in AJAX

The above is the detailed content of How PHP encapsulates XML. For more information, please follow other related articles on the PHP Chinese website!