I have a set of CSV data to convert to XML file using Java.

My issue is that I need to convert it in special format like this (XML properties format):

?xml version="1.0"?>
<root>
    <row col1="All" Col2="0" Col3="" Col4="0" Col5="0"></row>
    <row col1="All" Col2="935" Col3="231" Col4="0" Col5="30"></row>
    <row col1="None" Col2="1011" Col3="257" Col4="0" Col5="30"></row>
    .
    .
    ...
</root>

The function to convert my CSV dataset to XML is:

public void convertFile(String csvFileName, String xmlFileName,
          String delimiter) {

        try {
          Document newDoc = domBuilder.newDocument();
          // Root element
          Element rootElement = newDoc.createElement("root");
          newDoc.appendChild(rootElement);
          // Read csv file
          BufferedReader csvReader;
          csvReader = new BufferedReader(new FileReader(csvFileName));
          int fieldCount = 0;
          String[] csvFields = null;
          StringTokenizer stringTokenizer = null;

          String curLine = csvReader.readLine();
          if (curLine != null) {
            // how about other form of csv files?
            stringTokenizer = new StringTokenizer(curLine, delimiter);
            fieldCount = stringTokenizer.countTokens();
            if (fieldCount > 0) {
              csvFields = new String[fieldCount];
              int i = 0;
              while (stringTokenizer.hasMoreElements())
                csvFields[i  ] = String.valueOf(stringTokenizer.nextElement());
            }
          }

          while ((curLine = csvReader.readLine()) != null) {
            stringTokenizer = new StringTokenizer(curLine, delimiter);
            fieldCount = stringTokenizer.countTokens();
            if (fieldCount > 0) {
              Element rowElement = newDoc.createElement("row");
              int i = 0;
              while (stringTokenizer.hasMoreElements()) {
                try {
                  String curValue = String.valueOf(stringTokenizer.nextElement());
                  Element curElement = newDoc.createElement(csvFields[i  ]);
                  curElement.appendChild(newDoc.createTextNode(curValue));
                  rowElement.appendChild(curElement);
                } catch (Exception exp) {
                }
              }
              rootElement.appendChild(rowElement);

            }
          }
          csvReader.close();

          // Save the document to the disk file
          TransformerFactory tranFactory = TransformerFactory.newInstance();
          Transformer aTransformer = tranFactory.newTransformer();
          Source src = new DOMSource(newDoc);
          Result result = new StreamResult(new File(xmlFileName));
          aTransformer.transform(src, result);

          // Output to console for testing
          // Resultt result = new StreamResult(System.out);

        } catch (IOException exp) {
          System.err.println(exp.toString());
        } catch (Exception exp) {
          System.err.println(exp.toString());
        }

      }

But the the generated XML file was this and it is not the format that I'm looking for:

<dataset>
    <row>
        <Col1>All</Col1>
        <Col2>0</Col2>
        <Col3></Col3>
        <Col4>0</Col4>
        <Col5>0</Col5>
    </row>
    <row>
        <Col1>All</Col1>
        <Col2>935</Col2>
        <Col3>231</Col3>
        <Col4>0</Col4>
        <Col5>30</Col5>
    </row>
        <row>
        <Col1>None</Col1>
        <Col2>1011</Col2>
        <Col3>257</Col3>
        <Col4>0</Col4>
        <Col5>30</Col5>
    </row>
</dataset>

Could you please help me ?

CodePudding user response：

The easy way of parsing this is by converting the CSV to an object of the POJO class. Using Marshaller in java you can convert it to XML directly.

Yes, I agree your problem is you are getting results as elements instead of attributes. It can be easily configured in the POJO class as below.

@XmlAttribute(name = "") @XmlRootElement(name = "") @XmlElement(name = "")

Reference - https://howtodoinjava.com/jaxb/marshaller-example/

CodePudding user response：

I would prefer an OO approach too, as in - create a POJO and then process it to xml, but if you want a pure file to file approach, you could do something like this:

import java.io.File;
import javax.xml.transform.TransformerFactory;
import org.w3c.dom.Attr;
import org.w3c.dom.Element;
import javax.xml.transform.stream.StreamResult;

import javax.xml.transform.Transformer;
import org.w3c.dom.Document;
import javax.xml.parsers.DocumentBuilderFactory;

import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.Source;
import javax.xml.transform.Result;

import java.nio.file.Files;
import java.nio.file.Path;
import java.util.stream.Stream;
import java.util.List;

import java.util.concurrent.atomic.AtomicInteger;

public class Csv2Xml {

    private String[] headers;

    public static void main(String[] args) {
        try {
            new Csv2Xml().convertFile(args[0], args[1], "\\s*,\\s*");
        } catch (Throwable t) {
            t.printStackTrace();
        }
    }

    public void convertFile(String... args) {
        try {
            Document newDoc = DocumentBuilderFactory.newInstance().newDocumentBuilder().newDocument();
            // Root element
            Element rootElement = newDoc.createElement("root");
            newDoc.appendChild(rootElement);
            List<String> lines = Files.readAllLines(Path.of(args[0]));
            headers = lines.get(0).split(args[2]);
            lines.stream().skip(1).map(line -> line.split(args[2])).map(val -> toRow(newDoc, val))
                    .forEach(row -> rootElement.appendChild(row));
            // Save the document to the disk file
            TransformerFactory tranFactory = TransformerFactory.newInstance();
            Transformer aTransformer = tranFactory.newTransformer();
            Source src = new DOMSource(newDoc);
            Result result = new StreamResult(new File(args[1]));
            aTransformer.transform(src, result);

        } catch (Throwable t) {
            t.printStackTrace();
        }
    }

    private Element toRow(Document newDoc, String[] s) {
        Element row = newDoc.createElement("row");
        AtomicInteger index = new AtomicInteger(0);
        Stream.of(s).forEach(val -> {
            String attName = headers[index.getAndIncrement()];
            attName = sanitizeAttributeName(attName);
            Attr att = newDoc.createAttribute(attName);
            att.setNodeValue(val);
            row.setAttributeNode(att);
        });

        return row;
    }

    protected String sanitizeAttributeName(String attName) {
        final String BAD_CHARS = "[<>&'\",#~@;^$£()\\[\\]=]";
        return attName.replaceAll(" ", "_").replaceAll(BAD_CHARS, "");
    }

}