如何在java中解析XML以使用STAX在db中保存值？

Question

I am new to JAVA STAX Parser and I have to parse a xml to populate my database table.

While trying to read XML file using STAX I came across this problem. In an XML file, I may have child nodes with the same name in different root nodes. I couldn't quite figure out how to read specific child nodes from root nodes.

XML File Sample:-

<?xml version="1.0" encoding="UTF-8"?>
<DOC xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="XML.xsd">
<FMTR>
<TITLEPG>
  <TITLENUM>Title 1</TITLENUM>
  <SUBJECT>Test 1</SUBJECT>
</TITLEPG>
<BTITLE>
  <P></P>      
</BTITLE>
<TOC>
  <EXPL>
    <SUBJECT>Explanation</SUBJECT>
  </EXPL>
  <TITLENO>
    <CHAPTI>
      <SUBJECT>Chapter I—Test 1</SUBJECT>
    </CHAPTI>
  </TITLENO>
  <FAIDS>
    <SUBJECT>Table of Titles and Chapters</SUBJECT>
    <SUBJECT>Alphabetical List</SUBJECT>
  </FAIDS>
</TOC>
</FMTR>
</DOC>  

For eg:- I have to read the SUBJECT tag of TITLEPG root tag and populate the database table accordingly.

Can we get the child nodes of a root node using STAX?

What is the best approach to do parse it: STAX or JDOM ?

Answer 1

The XMLEventReader class in Java StAX is an Iterator based API for reading XML files. It will let you move from event to event in the XML, allowing you to decide when to move to the next event.

You are looking for "events" here. pls bear in mind Stax and xpath are very different things. Stax allows you to parse a streaming XML document in a forward direction only.

You can create an XMLEventReader via the javax.xml.stream.XMLInputFactory class. Try running demo code ( make changes as required) and you can see the object you want.

XMLInputFactory factory = XMLInputFactory.newInstance();

//get Reader connected to XML input from somewhere..
Reader reader = getXmlReader();

try {

    XMLEventReader eventReader =
    factory.createXMLEventReader(reader);

} catch (XMLStreamException e) {
    e.printStackTrace();
}

Now play around with this eventReader to get you what you want...iterate over it, see in debug mode,

while(eventReader.hasNext()){
   // this is what you want...
    XMLEvent event = eventReader.nextEvent();

    if(event.getEventType() == XMLStreamConstants.START_ELEMENT){
        StartElement startElement = event.asStartElement();
        System.out.println(startElement.getName().getLocalPart());
    }
    //handle more event types here...
}