1. Create
Create a new XML file and write some data into this XML file.
/*
* Create an xml file
*/
$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')
);//The data used to write
$dom = new DOMDocument('1.0');
$dom->formatOutput = true;//format
$eventList = $dom->createElement('EventList');//Create the root node EventList$dom->appendChild($eventList);//Add root node
for($i = 0; $i < count($info); $i++){
$event = $dom->createElement('event');//Create node event $text = $dom->createTextNode('PHP'.$i);//Create a text node, the value is PHP0, PHP1... $event->appendChild($text);//Add text node to node event as the value of node event
$attr_obj = $dom->createAttribute('obj');//Create attribute obj $attr_obj->value = $info[$i]['obj'];// Assign value to the obj attribute $event->appendChild($attr_obj);//Add the obj attribute to the event node as the attribute of the event node
$attr_info = $dom->createAttribute('info');
$attr_info->value = $info[$i]['info'];
$event->appendChild($attr_info);
$eventList->appendChild($event);//Add event node to root node EventList}
//echo $dom->saveXML();
$dom->save('./');//Save information to the file in the current directory
The above code snippet can create an XML file and add some information to this file, including values and properties. The final file is in the current directory. You can take a look at its contents.
<?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>
2. Read XML information & add new attributes
The file created in the above section is an operation object. It reads out the information in the file and adds a new attribute count to the node, with a value of 1.
/*
* Read xml file information and add new attributes
*/
$dom = new DOMDocument('1.0');
$dom->load('./');//Load the file to be operated$list = $dom->getElementsByTagName('event');//Get the event node listforeach($list as $item){
$attr_obj = $item->getAttribute('obj');//Get the value of the attribute obj $attr_info = $item->getAttribute('info');
echo "<pre>Object:$attr_obj;Info:$attr_info;Value:{$item->nodeValue}</pre>";
$item->setAttribute('count',1);//Add new attribute count=1}
$dom->save('./');//Save Modify
Take a look at the extracted values:
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
Let’s look at the contents of the current file. The count attribute has been added.
<?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>
3. Modify node attributes & node values
The file in the above section is an operation object. Change the count value of the node whose obj attribute is CPU, and the new value iscount+1 。
/*
* Modify the properties and values of a node
*/
$dom = new DOMDocument('1.0');
$dom->load('./');
$list = $dom->getElementsByTagName('event');
foreach($list as $item){
$attr_obj = $item->getAttribute('obj');
if($attr_obj == 'cpu'){//Modify the cpu count property to make its value +1 $attr_count = $item->getAttribute('count');//Get the value of the count attribute $item->setAttribute('count',$attr_count+1);//Reset the value of the count property $item->nodeValue = 'Hello,Kitty';//Reset the node's value }
}
$dom->save('./');
The file after operation is as follows, to seeobj=cpuThe count property of the node has been changed and the value has been modified successfully.
<?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>
4. Delete nodes
If you want to add, you will delete it. The files in the above section are operation objects, deletedobj=disknode.
/*
* Delete nodes
*/
$dom = new DOMDocument('1.0');
$dom->load('./');
$list = $dom->getElementsByTagName('event');
foreach($list as $item){
if($item->getAttribute('obj') == 'disk'){//The node with obj=disk is used as the operation object $item->parentNode->removeChild($item);//Delete node }
}
$dom->save('./');
Take a look at the file content after the operation. The obj=disk node has been successfully deleted.
<?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>
Add new child nodes to the root node
The above section is an operation object, adding a new child node to the root node EventList.
/*
* Add a child to EventList
*/
$dom = new DOMDocument('1.0');
$dom->load('./');
$event_list = $dom->getElementsByTagName('EventList');//Get the root node$event = $dom->createElement('event','lenovo');// Create a new node$event_list->item(0)->appendChild($event);//Add new node to root node
$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);
$dom->save('./');
Take a look at the file content after the operation. The new child node has been inserted into the root node.
<?xml version="1.0"?> <EventList> <event obj="power" info="power is shutdown" count="1">PHP0</event> <event obj="memcache" info="memcache used than 90%" count="1">PHP1</event> <event obj="cpu" info="cpu used than 95%" count="2">Hello,Kitty</event> <event obj="lenovo" info="thinkpad t430">lenovo</event></EventList>
5. About item($index)
item(index)It is a method in the DOMNodeList class, and its purpose is to return a node specified by the index. And the DOMDocument classgetElementsByTagName(name）The method returns an instance of the DOMNodeList object, so it can be called directly.item(index)method. The above section is an example, ife=dom−>getElementsByTagName(‘EventList′)Get information about the EventList node, because the EventList node is the root node, and there is only one, so when it calls item(index), only index=0 is available because it has only one; and ife=dom−>getElementsByTagName(‘event′)Get the information of the event node, because there are 4 events, so it callsitem(index)When indexing$index={0,1,2,3} , there are 4 values to choose. Each node contains multiple properties, which can be expressed in an array of key-value pairs, as shown below:
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/"
["textContent"]=>
string(11) "Hello,Kitty"
}
It can also be used as an object's attribute, for example, to obtain the value of this node:
/*
* About item()
*/
$dom = new DOMDocument('1.0');
$dom->load('./');
$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;
// }
Summarize
The above is the entire content of this article. I hope the content of this article will be helpful to everyone's learning or using PHP. If you have any questions, you can leave a message to communicate.