Good and effective CSV/TSV Reader for Java

Question

I am trying to read big CSV and TSV (tab-separated) Files with about 1000000 rows or more. Now I tried to read a TSV cont

Answer 1

Do not use a CSV parser to parse TSV inputs. It will break if the TSV has fields with a quote character, for example.

uniVocity-parsers comes with a TSV parser. You can parse a billion rows without problems.

Example to parse a TSV input:

TsvParserSettings settings = new TsvParserSettings();
TsvParser parser = new TsvParser(settings);

// parses all rows in one go.
List allRows = parser.parseAll(new FileReader(yourFile));

If your input is so big it can't be kept in memory, do this:

TsvParserSettings settings = new TsvParserSettings();

// all rows parsed from your input will be sent to this processor
ObjectRowProcessor rowProcessor = new ObjectRowProcessor() {
    @Override
    public void rowProcessed(Object[] row, ParsingContext context) {
        //here is the row. Let's just print it.
        System.out.println(Arrays.toString(row));
    }
};
// the ObjectRowProcessor supports conversions from String to whatever you need:
// converts values in columns 2 and 5 to BigDecimal
rowProcessor.convertIndexes(Conversions.toBigDecimal()).set(2, 5);

// converts the values in columns "Description" and "Model". Applies trim and to lowercase to the values in these columns.
rowProcessor.convertFields(Conversions.trim(), Conversions.toLowerCase()).set("Description", "Model");

//configures to use the RowProcessor
settings.setRowProcessor(rowProcessor);

TsvParser parser = new TsvParser(settings);
//parses everything. All rows will be pumped into your RowProcessor.
parser.parse(new FileReader(yourFile));

Disclosure: I am the author of this library. It's open-source and free (Apache V2.0 license).