Java XML reading (using Dom + XPath)

The following math. xml file is used as the example XML file. The document shows the math score of an exam, which contains the score of student LZX and ZJ.

 

------------- Math. xml -------------

<Math>

<Student ID = "1">

<Name> ZJ </Name>

<Score> 87 </score>

</Student>

<Student ID = "2">

<Name> LZX </Name>

<Score> 85 </score>

</Student>

</Math>

-------------------------------------

Perform the following operations:

 

1. Read math. XML to memory

Documentbuilderfactory DBF = documentbuilderfactory.Newinstance();

Documentbuilder DB = DBF. newdocumentbuilder ();

File F =NewFile ("D:" "math. xml ");

Document Doc = dB. parse (f );

 

2. Obtain the student node list

Xpathfactory = xpathfactory.Newinstance();

XPath = xpathfactory. newxpath ();

Nodelist list = (nodelist) XPath. Evaluate ("Math/student", doc,

Xpathconstants.Nodeset);

 

3. Obtain the first node with student as the node.

Xpathfactory = xpathfactory.Newinstance();

XPath = xpathfactory. newxpath ();

Node node = (node) XPath. Evaluate ("Math/student", doc,

Xpathconstants.Node);

 

Complex functions can be implemented based on the DOM tree structure and XPath path.

XPath Syntax: http://www.w3school.com.cn/xpath/xpath_syntax.asp