Reading xml file from java

Question

I am trying to create a GUI interface for user login in java swing. I am trying to store my data in an Xml file and I need to access it from java and check if the user name and password entered in the GUI matches with any of the given user details in the xml data. If it matches they are given access to the next level.

I am trying to use SAX parser for accessing the Xml file . I am unable to understand how the SAX parser works and how it can be used for matching with the input from the GUI.

Please help. Thanks for all your help in advance.

DOM or JAXB are a better model than SAX, unless your XML file is huge — artbristol, Mar 29 '12 at 10:02

score 2 · Answer 1 · answered Mar 29 '12 at 10:00

you could use Jaxb if you have model your document:

JAXBContext jc = JAXBContext.newInstance("myPackageName");
//Create unmarshaller
Unmarshaller um = jc.createUnmarshaller();
//Unmarshal XML contents of the file myDoc.xml into your Java object instance.
MyJAXBObject myJAXBObject = (MyJAXBObject) 
    um.unmarshal(new java.io.FileInputStream( "myDoc.xml" ));

you can easily validate it if you have a schema of your model

here there is an example

http://www.mkyong.com/java/jaxb-hello-world-example/

score 0 · Answer 2 · answered Mar 29 '12 at 09:45

0

for each of your GUI elements you should get text and for open XML and parse it check THIS CODE out, it will be helpful

answered Mar 29 '12 at 09:45

Maziar Aboualizadehbehbahani

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score 0 · Answer 3 · answered Mar 29 '12 at 11:16

You can do this way

DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder docBuilder = docFactory.newDocumentBuilder();
Document doc = docBuilder.parse("/home/riddhish/developerworkspace/SplitString/src/com/updatexmlwithjava/two.xml");

NodeList username = doc.getElementsByTagName("username");           
System.out.println("username ="+username.item(0).getTextContent());
NodeList password = doc.getElementsByTagName("password");           
System.out.println("password ="+password.item(0).getTextContent());

score 0 · Answer 4 · answered Mar 29 '12 at 11:56

SAX Parser works differently from DOM/JAXB. With DOM, the XML content wil accessible via DOM generated node/element. Using SAX, the parser will read through your XML file, and than via event it will notice the content handler such like :

Start tag
End tag

With information such as tag attributes, content etc.

Example :

public class TagHandler extends DefaultHandler{

//tag opening detection
public void startElement(String uri, String localName,
        String qName, Attributes attributes) throws SAXException{
    // ... your code
}
//tag closing detection
public void endElement(String uri, String localName, String qName)
        throws SAXException{
    // ... your code
}

}

There is more than that two events mentioned.

I Hope that will help you to understand SAX better

Reading xml file from java

4 Answers4