Java lib or app to convert CSV to XML file? [closed]

Question

Maybe this might help: JSefa

You can read CSV file with this tool and serialize it to XML.

As the others above, I don't know any one-step way to do that, but if you are ready to use very simple external libraries, I would suggest:

OpenCsv for parsing CSV (small, simple, reliable and easy to use)

Xstream to parse/serialize XML (very very easy to use, and creating fully human readable xml)

Using the same sample data as above, code would look like:

package fr.megiste.test;

import java.io.FileReader;
import java.io.FileWriter;
import java.util.ArrayList;
import java.util.List;

import au.com.bytecode.opencsv.CSVReader;

import com.thoughtworks.xstream.XStream;

public class CsvToXml {     

    public static void main(String[] args) {

        String startFile = "./startData.csv";
        String outFile = "./outData.xml";

        try {
            CSVReader reader = new CSVReader(new FileReader(startFile));
            String[] line = null;

            String[] header = reader.readNext();

            List out = new ArrayList();

            while((line = reader.readNext())!=null){
                List<String[]> item = new ArrayList<String[]>();
                    for (int i = 0; i < header.length; i++) {
                    String[] keyVal = new String[2];
                    String string = header[i];
                    String val = line[i];
                    keyVal[0] = string;
                    keyVal[1] = val;
                    item.add(keyVal);
                }
                out.add(item);
            }

            XStream xstream = new XStream();

            xstream.toXML(out, new FileWriter(outFile,false));

        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

Producing the following result: (Xstream allows very fine tuning of the result...)

<list>
  <list>
    <string-array>
      <string>string</string>
      <string>hello world</string>
    </string-array>
    <string-array>
      <string>float1</string>
      <string>1.0</string>
    </string-array>
    <string-array>
      <string>float2</string>
      <string>3.3</string>
    </string-array>
    <string-array>
      <string>integer</string>
      <string>4</string>
    </string-array>
  </list>
  <list>
    <string-array>
      <string>string</string>
      <string>goodbye world</string>
    </string-array>
    <string-array>
      <string>float1</string>
      <string>1e9</string>
    </string-array>
    <string-array>
      <string>float2</string>
      <string>-3.3</string>
    </string-array>
    <string-array>
      <string>integer</string>
      <string>45</string>
    </string-array>
  </list>
  <list>
    <string-array>
      <string>string</string>
      <string>hello again</string>
    </string-array>
    <string-array>
      <string>float1</string>
      <string>-1</string>
    </string-array>
    <string-array>
      <string>float2</string>
      <string>23.33</string>
    </string-array>
    <string-array>
      <string>integer</string>
      <string>456</string>
    </string-array>
  </list>
  <list>
    <string-array>
      <string>string</string>
      <string>hello world 3</string>
    </string-array>
    <string-array>
      <string>float1</string>
      <string>1.40</string>
    </string-array>
    <string-array>
      <string>float2</string>
      <string>34.83</string>
    </string-array>
    <string-array>
      <string>integer</string>
      <string>4999</string>
    </string-array>
  </list>
  <list>
    <string-array>
      <string>string</string>
      <string>hello 2 world</string>
    </string-array>
    <string-array>
      <string>float1</string>
      <string>9981.05</string>
    </string-array>
    <string-array>
      <string>float2</string>
      <string>43.33</string>
    </string-array>
    <string-array>
      <string>integer</string>
      <string>444</string>
    </string-array>
  </list>
</list>

I know you asked for Java, but this strikes me as a task well suited to a scripting language. Here is a quick (very simple) solution written in Groovy.

test.csv

string,float1,float2,integer
hello world,1.0,3.3,4
goodbye world,1e9,-3.3,45
hello again,-1,23.33,456
hello world 3,1.40,34.83,4999
hello 2 world,9981.05,43.33,444

csvtoxml.groovy

#!/usr/bin/env groovy

def csvdata = []
new File("test.csv").eachLine { line ->
    csvdata << line.split(',')
}

def headers = csvdata[0]
def dataRows = csvdata[1..-1]

def xml = new groovy.xml.MarkupBuilder()

// write 'root' element
xml.root {
    dataRows.eachWithIndex { dataRow, index ->
        // write 'entry' element with 'id' attribute
        entry(id:index+1) {
            headers.eachWithIndex { heading, i ->
                // write each heading with associated content
                "${heading}"(dataRow[i])
            }
        }
    }
}

Writes the following XML to stdout:

<root>
  <entry id='1'>
    <string>hello world</string>
    <float1>1.0</float1>
    <float2>3.3</float2>
    <integer>4</integer>
  </entry>
  <entry id='2'>
    <string>goodbye world</string>
    <float1>1e9</float1>
    <float2>-3.3</float2>
    <integer>45</integer>
  </entry>
  <entry id='3'>
    <string>hello again</string>
    <float1>-1</float1>
    <float2>23.33</float2>
    <integer>456</integer>
  </entry>
  <entry id='4'>
    <string>hello world 3</string>
    <float1>1.40</float1>
    <float2>34.83</float2>
    <integer>4999</integer>
  </entry>
  <entry id='5'>
    <string>hello 2 world</string>
    <float1>9981.05</float1>
    <float2>43.33</float2>
    <integer>444</integer>
  </entry>
</root>

However, the code does very simple parsing (not taking into account quoted or escaped commas) and it does not account for possible absent data.

I have an opensource framework for working with CSV and flat files in general. Maybe it's worth looking: JFileHelpers.

With that toolkit you can write code using beans, like:

@FixedLengthRecord()
public class Customer {
    @FieldFixedLength(4)
    public Integer custId;

    @FieldAlign(alignMode=AlignMode.Right)
    @FieldFixedLength(20)
    public String name;

    @FieldFixedLength(3)
    public Integer rating;

    @FieldTrim(trimMode=TrimMode.Right)
    @FieldFixedLength(10)
    @FieldConverter(converter = ConverterKind.Date, 
    format = "dd-MM-yyyy")
    public Date addedDate;

    @FieldFixedLength(3)
    @FieldOptional
    public String stockSimbol;  
}

and then just parse your text files using:

FileHelperEngine<Customer> engine = 
    new FileHelperEngine<Customer>(Customer.class); 
List<Customer> customers = 
    new ArrayList<Customer>();

customers = engine.readResource(
    "/samples/customers-fixed.txt");

And you'll have a collection of parsed objects.

Hope that helps!

This solution does not need any CSV or XML libraries and, I know, it does not handle any illegal characters and encoding issues, but you might be interested in it as well, provided your CSV input does not break the above mentioned rules.

Attention: You should not use this code unless you know what you do or don't have the chance to use a further library (possible in some bureaucratic projects)... Use a StringBuffer for older Runtime Environments...

So here we go:

BufferedReader reader = new BufferedReader(new InputStreamReader(
        Csv2Xml.class.getResourceAsStream("test.csv")));
StringBuilder xml = new StringBuilder();
String lineBreak = System.getProperty("line.separator");
String line = null;
List<String> headers = new ArrayList<String>();
boolean isHeader = true;
int count = 0;
int entryCount = 1;
xml.append("<root>");
xml.append(lineBreak);
while ((line = reader.readLine()) != null) {
    StringTokenizer tokenizer = new StringTokenizer(line, ",");
    if (isHeader) {
        isHeader = false;
        while (tokenizer.hasMoreTokens()) {
            headers.add(tokenizer.nextToken());
        }
    } else {
        count = 0;
        xml.append("\t<entry id=\"");
        xml.append(entryCount);
        xml.append("\">");
        xml.append(lineBreak);
        while (tokenizer.hasMoreTokens()) {
            xml.append("\t\t<");
            xml.append(headers.get(count));
            xml.append(">");
            xml.append(tokenizer.nextToken());
            xml.append("</");
            xml.append(headers.get(count));
            xml.append(">");
            xml.append(lineBreak);
            count++;
        }
        xml.append("\t</entry>");
        xml.append(lineBreak);
        entryCount++;
    }
}
xml.append("</root>");
System.out.println(xml.toString());

The input test.csv (stolen from another answer on this page):

string,float1,float2,integer
hello world,1.0,3.3,4
goodbye world,1e9,-3.3,45
hello again,-1,23.33,456
hello world 3,1.40,34.83,4999
hello 2 world,9981.05,43.33,444

The resulting output:

<root>
    <entry id="1">
        <string>hello world</string>
        <float1>1.0</float1>
        <float2>3.3</float2>
        <integer>4</integer>
    </entry>
    <entry id="2">
        <string>goodbye world</string>
        <float1>1e9</float1>
        <float2>-3.3</float2>
        <integer>45</integer>
    </entry>
    <entry id="3">
        <string>hello again</string>
        <float1>-1</float1>
        <float2>23.33</float2>
        <integer>456</integer>
    </entry>
    <entry id="4">
        <string>hello world 3</string>
        <float1>1.40</float1>
        <float2>34.83</float2>
        <integer>4999</integer>
    </entry>
    <entry id="5">
        <string>hello 2 world</string>
        <float1>9981.05</float1>
        <float2>43.33</float2>
        <integer>444</integer>
    </entry>
</root>

I don't understand why you would want to do this. It sounds almost like cargo cult coding.

Converting a CSV file to XML doesn't add any value. Your program is already reading the CSV file, so arguing that you need XML doesn't work.

On the other hand, reading the CSV file, doing something with the values, and then serializing to XML does make sense (well, as much as using XML can make sense... ;)) but you would supposedly already have a means of serializing to XML.