解析XML，跳过某些标签

Question

I am following mkyong's great tutorial on how to parse xml in Java, but I have a situation where I need to read certain tags but only within an area. eg

<?xml version="1.0"?>
<company>
    <staff id="1001">
        <firstname>yong</firstname>
        <lastname>mook kim</lastname>
        <nickname>mkyong</nickname>
        <salary>100000</salary>
    </staff>
    <staff id="2001">
        <firstname>low</firstname>
        <lastname>yin fong</lastname>
        <nickname>fong fong</nickname>
        <salary>200000</salary>
    </staff>
    <changes>
        <staff id="2001">
            <firstname>low</firstname>
            <lastname>yin fong</lastname>
            <nickname>fong fong</nickname>
            <old_salary>175000</salary>
            <new_salary>200000</salary>
        </staff>
    </changes>
</company>

In the tutorial it uses NodeList nList = doc.getElementsByTagName("staff"); but this retrieves all of the staff, including the one under <changes> . How can I disregard all <staff> tags under <changes> ?

Thanks

Answer 1

Using DOM parser is not the best for your need. Using XPath queries should be better. ( API )

For exemple :

    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
    DocumentBuilder db = dbf.newDocumentBuilder(); 
    Document doc = db.parse(new File("test.xml"));

    XPath xPath =  XPathFactory.newInstance().newXPath();
    String expression = "/company/staff";

    //read a nodelist using xpath
    NodeList nodeList = (NodeList) xPath.compile(expression).evaluate(doc, XPathConstants.NODESET);

Answer 2

When you are applying the items that you are intending to save you can attempt to catch it if it is under changes and then ignore it. ex

 if(company.changes != null)
{
//skip saving this node

}