详解PHP原生DOM对象操作XML的方法

/*
 * 创建xml文件
 */
 
$info = array(
 array('obj' => 'power','info' => 'power is shutdown'),
 array('obj' => 'memcache','info' => 'memcache used than 90%'),
 array('obj' => 'cpu','info' => 'cpu used than 95%'),
 array('obj' => 'disk','info' => 'disk is removed')
);//用来写入的数据
 
$dom = new DOMDocument('1.0');
$dom->formatOutput = true;//格式化
 
$eventList = $dom->createElement('EventList');//创建根节点EventList
$dom->appendChild($eventList);//添加根节点
 
for($i = 0; $i < count($info); $i  ){
 $event = $dom->createElement('event');//创建节点event
 $text = $dom->createTextNode('PHP'.$i);//创建文本节点，值为PHP0,PHP1...
 $event->appendChild($text);//将文本节点添加到节点event，做为节点event的值
 
 $attr_obj = $dom->createAttribute('obj');//创建属性obj
 $attr_obj->value = $info[$i]['obj'];//为obj属性赋值
 $event->appendChild($attr_obj);//将obj属性添加到event节点中，做为event节点的属性
 
 $attr_info = $dom->createAttribute('info');
 $attr_info->value = $info[$i]['info'];
 $event->appendChild($attr_info);
 
 $eventList->appendChild($event);//将event节点添加到根节点EventList中
}
 
//echo $dom->saveXML();
$dom->save('./t.xml');//保存信息到当前目录下的t.xml文件中

<?xml version="1.0"?>
<EventList>
 <event obj="power" info="power is shutdown">PHP0</event>
 <event obj="memcache" info="memcache used than 90%">PHP1</event>
 <event obj="cpu" info="cpu used than 95%">PHP2</event>
 <event obj="disk" info="disk is removed">PHP3</event>
</EventList>

/*
 * 读取xml文件信息，并添加新的属性
 */
 
$dom = new DOMDocument('1.0');
$dom->load('./t.xml');//加载要操作的文件
$list = $dom->getElementsByTagName('event');//获取event节点列表
foreach($list as $item){
 $attr_obj = $item->getAttribute('obj');//获取属性obj的值
 $attr_info = $item->getAttribute('info');
 echo "<pre>Object:$attr_obj;Info:$attr_info;Value:{$item->nodeValue}</pre>";
 $item->setAttribute('count',1);//添加新的属性count=1
}
$dom->save('./t.xml');//保存修改

Object:power;Info:power is shutdown;Value:PHP0
 
Object:memcache;Info:memcache used than 90%;Value:PHP1
 
Object:cpu;Info:cpu used than 95%;Value:PHP2
 
Object:disk;Info:disk is removed;Value:PHP3

<?xml version="1.0"?>
<EventList>
 <event obj="power" info="power is shutdown" count="1">PHP0</event>
 <event obj="memcache" info="memcache used than 90%" count="1">PHP1</event>
 <event obj="cpu" info="cpu used than 95%" count="1">PHP2</event>
 <event obj="disk" info="disk is removed" count="1">PHP3</event>
</EventList>

/*
 * 修改某一个节点的属性和值
 */
 
$dom = new DOMDocument('1.0');
$dom->load('./t.xml');
$list = $dom->getElementsByTagName('event');
foreach($list as $item){
 $attr_obj = $item->getAttribute('obj');
 if($attr_obj == 'cpu'){//修改cpu的count属性，使其值 1
  $attr_count = $item->getAttribute('count');//获取count属性的值
  $item->setAttribute('count',$attr_count 1);//重置count属性的值
  $item->nodeValue = 'Hello,Kitty';//重置节点的值
 }
}
$dom->save('./t.xml');

<?xml version="1.0"?>
<EventList>
 <event obj="power" info="power is shutdown" count="1">PHP0</event>
 <event obj="memcache" info="memcache used than 90%" count="1">PHP1</event>
 <event obj="cpu" info="cpu used than 95%" count="2">Hello,Kitty</event>
 <event obj="disk" info="disk is removed" count="1">PHP3</event>
</EventList>

/*
 * 删除节点
 */
 
$dom = new DOMDocument('1.0');
$dom->load('./t.xml');
$list = $dom->getElementsByTagName('event');
foreach($list as $item){
 if($item->getAttribute('obj') == 'disk'){//以obj=disk的节点为操作对象
  $item->parentNode->removeChild($item);//删除节点
 }
}
$dom->save('./t.xml');

<?xml version="1.0"?>
<EventList>
 <event obj="power" info="power is shutdown" count="1">PHP0</event>
 <event obj="memcache" info="memcache used than 90%" count="1">PHP1</event>
 <event obj="cpu" info="cpu used than 95%" count="2">Hello,Kitty</event>
 
</EventList>

/*
 * 向EventList中添加一个子节点
 */
 
$dom = new DOMDocument('1.0');
$dom->load('./t.xml');
$event_list = $dom->getElementsByTagName('EventList');//获取根节点
$event = $dom->createElement('event','lenovo');//新建节点
$event_list->item(0)->appendChild($event);//将新建节点添加到根节点中
 
$event_attr_obj = $dom->createAttribute('obj');
$event_attr_obj->value = 'lenovo';
$event->appendChild($event_attr_obj);
 
$event_attr_info = $dom->createAttribute('info');
$event_attr_info->value = 'thinkpad t430';
$event->appendChild($event_attr_info);
 
$dom->save('./t.xml');

<?xml version="1.0"?>
<EventList>
 <event obj="power" info="power is shutdown" count="1">PHP0</event>
 <event obj="memcache" info="memcache used than 90%" count="1">PHP1</event>
 <event obj="cpu" info="cpu used than 95%" count="2">Hello,Kitty</event>
 
<event obj="lenovo" info="thinkpad t430">lenovo</event></EventList>

object(DOMElement)#3 (18) {
 ["tagName"]=>
 string(5) "event"
 ["schemaTypeInfo"]=>
 NULL
 ["nodeName"]=>
 string(5) "event"
 ["nodeValue"]=>
 string(11) "Hello,Kitty"
 ["nodeType"]=>
 int(1)
 ["parentNode"]=>
 string(22) "(object value omitted)"
 ["childNodes"]=>
 string(22) "(object value omitted)"
 ["firstChild"]=>
 string(22) "(object value omitted)"
 ["lastChild"]=>
 string(22) "(object value omitted)"
 ["previousSibling"]=>
 string(22) "(object value omitted)"
 ["nextSibling"]=>
 string(22) "(object value omitted)"
 ["attributes"]=>
 string(22) "(object value omitted)"
 ["ownerDocument"]=>
 string(22) "(object value omitted)"
 ["namespaceURI"]=>
 NULL
 ["prefix"]=>
 string(0) ""
 ["localName"]=>
 string(5) "event"
 ["baseURI"]=>
 string(36) "file:/H:/xampp/htdocs/demo/xml/t.xml"
 ["textContent"]=>
 string(11) "Hello,Kitty"
}

/*
 * 关于item()
 */
$dom = new DOMDocument('1.0');
$dom->load('./t.xml');
$e = $dom->getElementsByTagName('event');
echo $e->item(2)->nodeValue;
//var_dump($e->item(2));
// $e = $dom->getElementsByTagName('EventList');
// var_dump($e->item(0));
//var_dump($e->item(0)->baseURI);
// for($i=0;$i<$e->length;$i  ){
//  echo $e->item($i)->nodeValue;
// }