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May 5th, 2008, 02:00 PM

Java_Chick

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XML parser in Java

I have to make XML parser, for the xml file I have.I wrote the code for reading it, but I need just an example for a part of code.

This is what I made so far:

Code:

import java.io.BufferedInputStream;
import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.regex.*;

public class Main {

  public static void main(String[] args) {

    File file = new File("C:/EES.xml");
    FileInputStream fis = null;
    BufferedInputStream bis = null;
    DataInputStream dis = null;

    try {
      fis = new FileInputStream(file);

     
      bis = new BufferedInputStream(fis);
      dis = new DataInputStream(bis);

      while (dis.available() != 0) {


        System.out.println(dis.readLine());
      }

      fis.close();
      bis.close();
      dis.close();

    } catch (FileNotFoundException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    }
  }
}

This is XML file:

Code:

<?xml version="1.0" encoding="utf-8"?>

<Circuit>

<Elements>

<E1>
<value>20</value>
</E1>

<E2>
<value>10</value>
</E2>

<R1>
<value>120</value>
</R1>

<R2>
<value>100</value>
</R2>

</Elements> 
<!--In this part I'm just telling which elements exist (elements of an electronic circuit, doesn't matter now), and their values.I should assing variables for each value, so latter on I could solve math equations system.Also, every element should in the start get two points:A and B-->


<Linking>

<E12>
<A>R1A</A>
<B>R2A</B>
</E12>

<E23>
<A>R1A</A>
<B>R2B</B>
</E23>

<R12>
<A>E1A</A>
<B>R2A,E1B</B>    
<!--when their is a ",", it means that the element is linked with two other elements, it's in "parallel" whith them-->
</R12>

<R23>
<A>R1B,E1B</A>
<B>E2B</B>
</R23>

</Linking> 
<!--Now every A and B spot has it's pair ( or more pairs ) - the other part of some element.This is the job of a parser, latter comes math-->

</Circuit>

For me it's a bit complicated, but If someone could just write me a part of the code, example for E1 tag in Elements tag, I could write the rest.

May 28th, 2008, 12:57 PM

Morphine

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An example:

With this XML code:
XML File

Code:

<book>
<person>
  <first>Kiran</first>
  <last>Pai</last>
  <age>22</age>
</person>
<person>
  <first>Bill</first>
  <last>Gates</last>
  <age>46</age>
</person>
<person>
  <first>Steve</first>
  <last>Jobs</last>
  <age>40</age>
</person>
</book>

This could be a solution:

Code:

import java.io.File;
import org.w3c.dom.Document;
import org.w3c.dom.*;

import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.DocumentBuilder;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException; 

public class ReadAndPrintXMLFile{

    public static void main (String argv []){
    try {

            DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory.newInstance();
            DocumentBuilder docBuilder = docBuilderFactory.newDocumentBuilder();
            Document doc = docBuilder.parse (new File("book.xml"));

            // normalize text representation
            doc.getDocumentElement ().normalize ();
            System.out.println ("Root element of the doc is " + 
                 doc.getDocumentElement().getNodeName());


            NodeList listOfPersons = doc.getElementsByTagName("person");
            int totalPersons = listOfPersons.getLength();
            System.out.println("Total no of people : " + totalPersons);

            for(int s=0; s<listOfPersons.getLength() ; s++){


                Node firstPersonNode = listOfPersons.item(s);
                if(firstPersonNode.getNodeType() == Node.ELEMENT_NODE){


                    Element firstPersonElement = (Element)firstPersonNode;

                    //-------
                    NodeList firstNameList = firstPersonElement.getElementsByTagName("first");
                    Element firstNameElement = (Element)firstNameList.item(0);

                    NodeList textFNList = firstNameElement.getChildNodes();
                    System.out.println("First Name : " + 
                           ((Node)textFNList.item(0)).getNodeValue().trim());  

                    //-------
                    NodeList lastNameList = firstPersonElement.getElementsByTagName("last");
                    Element lastNameElement = (Element)lastNameList.item(0);

                    NodeList textLNList = lastNameElement.getChildNodes();
                    System.out.println("Last Name : " + 
                           ((Node)textLNList.item(0)).getNodeValue().trim());  

                    //----
                    NodeList ageList = firstPersonElement.getElementsByTagName("age");
                    Element ageElement = (Element)ageList.item(0);

                    NodeList textAgeList = ageElement.getChildNodes();
                    System.out.println("Age : " + 
                           ((Node)textAgeList.item(0)).getNodeValue().trim())  ;

                    //------


                }//end of if clause


            }//end of for loop with s var


        }catch (SAXParseException err) {
        System.out.println ("** Parsing error" + ", line " 
             + err.getLineNumber () + ", uri " + err.getSystemId ());
        System.out.println(" " + err.getMessage ());

        }catch (SAXException e) {
        Exception x = e.getException ();
        ((x == null) ? e : x).printStackTrace ();

        }catch (Throwable t) {
        t.printStackTrace ();
        }
        //System.exit (0);

    }//end of main


}

May 28th, 2008, 01:00 PM

Java_Chick

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Join Date: May 2008

Posts: 2

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Thanks, but I solved the problem

I did it in Pascal, since is easier for doing with text files..

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