Java lib or app to convert CSV to XML file?


Answers

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>
Question

Is there an existing application or library in Java which will allow me to convert a CSV data file to XML file?

The XML tags would be provided through possibly the first row containing column headings.







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 may be too basic or limited of a solution, but couldn't you do a String.split() on each line of the file, remembering the result array of the first line to generate the XML, and just spit each line's array data out with the proper XML elements padding each iteration of a loop?




As far as I know, there's no ready-made library to do this for you, but producing a tool capable of translating from CSV to XML should only require you to write a crude CSV parser and hook up JDOM (or your XML Java library of choice) with some glue code.




The big difference is that JSefa brings in is that it can serialize your java objects to CSV/XML/etc files and can deserialize back to java objects. And it's driven by annotations which gives you lot of control over the output.

JFileHelpers also looks interesting.




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.




There is also good library ServingXML by Daniel Parker, which is able to convert almost any plain text format to XML and back.

The example for your case can be found here: It uses heading of field in CSV file as the XML element name.




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