DOM (Document Object Model): Document Object Model. The core idea is: treat the xml file as an object model, and then operate the xml file through objects.
PHP performs addition, deletion, modification and query (curd) operations on xml documents. The specific analysis is as follows:
xml document: class.xml
The code is as follows:
DOM tree structure diagram corresponding to class.xml
php file (operating on xml document)
Query operation cases:
The code is as follows:
//3.2 Read the first student
$stu1 = $students->item(0);//Read the first student. The return value is a DOMElement object. Directly echo $stu1->nodeValue; will output name, sex, and age.
//3.3 Get the first student’s name
$stu1_name = $stu1->getElementsByTagName("name");
//3.4 Read the name
echo $stu1_name->item(0)->nodeValue;
?>
Note:
(1) Encoding problem;
(2) This is just a basic demonstration, which is quite troublesome. Loops and functions will be used later;
(3) Use var_dump() to check the return value of the variable, and then use the return value to find the attributes and methods under the return value in the manual.
(4) After the entire sequence, getElementByTagName() does not need to read layer by layer. In fact, it can directly read the node name without reading the student first (of course, if there are multiple students under the same student name, there will be a problem, and you need to learn new knowledge points here (xpath).
So the above code can be simply changed to:
The code is as follows: