Fork me on GitHub

Writing CSV files with CsvResultSetWriter

This page contains an example of writing a CSV file using Super CSV CsvResultSetWriter. You can view the full source of the example here.

Example cell processor configuration

Example use the following cell processor configuration.

It demonstrates:

  • mandatory columns (new NotNull())
  • optional columns (new Optional()), with further processing
  • formatting of Dates (new FmtDate()) and Booleans (new FmtBool())
  • constraint validation of numeric ranges (new LMinMax()) and uniqueness (new UniqueHashCode())

Don't forget that you can write your own cell processors if you want!

 * Sets up the processors used for the examples. There are 10 CSV columns, so 10 processors are defined. All values
 * are converted to Strings before writing (there's no need to convert them), and null values will be written as
 * empty columns (no need to convert them to "").
 * @return the cell processors
private static CellProcessor[] getProcessors() {
        final CellProcessor[] processors = new CellProcessor[] { 
                new UniqueHashCode(), // customerNo (must be unique)
                new NotNull(), // firstName
                new NotNull(), // lastName
                new FmtDate("dd/MM/yyyy"), // birthDate
                new NotNull(), // mailingAddress
                new Optional(new FmtBool("Y", "N")), // married
                new Optional(), // numberOfKids
                new NotNull(), // favouriteQuote
                new NotNull(), // email
                new LMinMax(0L, LMinMax.MAX_LONG) // loyaltyPoints
        return processors;

Writing with CsvResultSetWriter

The example writes a mock implementation of java.sql.ResultSet to a CSV file.

Note that the cell processors are compatible with their associated field types in the ResultSet (e.g. birthDate is a java.util.Date in the ResultSet, and uses the FmtDate cell processor).

 * An example of writing using CsvResultSetWriter
private static void writeWithResultSetWriter() throws Exception {
        // create ResultSet mock
        final String[] header = new String[] { "customerNo", "firstName", "lastName", "birthDate",
                "mailingAddress", "married", "numberOfKids", "favouriteQuote", "email", "loyaltyPoints" };
        final Object[][] johnData = new Object[][] {{"1", "John", "Dunbar",
                new GregorianCalendar(1945, Calendar.JUNE, 13).getTime(),
                "1600 Amphitheatre Parkway\nMountain View, CA 94043\nUnited States", null, null,
                "\"May the Force be with you.\" - Star Wars", "", 0L}};
        final ResultSet john = new ResultSetMock(johnData, header);
        final Object[][] bobData = new Object[][] {{"2", "Bob", "Down",
                new GregorianCalendar(1919, Calendar.FEBRUARY, 25).getTime(),
                "1601 Willow Rd.\nMenlo Park, CA 94025\nUnited States", true, 0,
                "\"Frankly, my dear, I don't give a damn.\" - Gone With The Wind", "", 123456L}};
        final ResultSet bob = new ResultSetMock(bobData, header);
        ICsvResultSetWriter resultSetWriter = null;
        try {
                resultSetWriter = new CsvResultSetWriter(new FileWriter("target/writeWithCsvResultSetWriter.csv"),
                final CellProcessor[] processors = getProcessors();
                // writer csv file from ResultSet
                resultSetWriter.write(john, processors);
                resultSetWriter.write(bob, processors);
        } finally {
                if ( resultSetWriter != null ) {


1,John,Dunbar,13/06/1945,"1600 Amphitheatre Parkway
Mountain View, CA 94043
United States",,,"""May the Force be with you."" - Star Wars",,0
2,Bob,Down,25/02/1919,"1601 Willow Rd.
Menlo Park, CA 94025
United States",Y,0,"""Frankly, my dear, I don't give a damn."" - Gone With The Wind",,123456