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FastCSV FastCSV

Migrating from 2.x

This document only describes the breaking changes when migrating from FastCSV 2.x to 3.x. For a full list of changes, including new features, see the changelog.

Requirement changes

  • The minimum Java version is now 11 (compared to 8 in earlier versions)
  • This also raised the required Android API level from version 26 (Android 8) to 33 (Android 13)

New limitations

  • The maximum number of fields per record is now limited to 16,384 to avoid OutOfMemoryErrors caused by excessive field counts.
  • The maximum record size is now limited to (64 MiB) to prevent OutOfMemoryErrors.

Naming changes

Rows are now called Records (aligned to RFC 4180)

Reading CSV records:

try (CsvReader<CsvRecord> csv = CsvReader.builder().ofCsvRecord(file)) {
    csv.forEach(System.out::println);
}

Write CSV records:

try (CsvWriter csv = CsvWriter.builder().build(file)) {
    csv
        .writeRecord("header1", "header2")
        .writeRecord("value1", "value2");
}

Method names

  • In CsvReaderBuilder:
    • skipEmptyRows is now skipEmptyLines
    • errorOnDifferentFieldCount is now ignoreDifferentFieldCount (opposite meaning!)
    • build methods with callback handlers and ofCsvRecord / ofNamedCsvRecord as convenience methods
  • In CsvRecord (former CsvRow):
    • getOriginalLineNumber is now getStartingLineNumber

NamedCsvReader removed/replaced

A distinct NamedCsvReader is no longer needed as the CsvReader now supports callbacks for header and record processing.

CsvReader.builder().ofNamedCsvRecord("header 1,header 2\nfield 1,field 2")
    .forEach(rec -> System.out.println(rec.getField("header2")));

or with a custom header:

CsvCallbackHandler<NamedCsvRecord> callbackHandler =
    new NamedCsvRecordHandler("header1", "header2");


CsvReader.builder().build(callbackHandler, "field 1,field 2")
    .forEach(rec -> System.out.println(rec.getField("header2")));

Extended/Refactored quote strategies

  • QuoteStrategy changed from an enum to an interface (see QuoteStrategies for the default implementations)
  • The REQUIRED quote strategy is removed as it is the default (no quote strategy is needed)

Example to enable always quoting:

CsvWriter.builder()
    .quoteStrategy(QuoteStrategies.ALWAYS);

Exception changes

MalformedCsvException is now CsvParseException and is thrown instead of IOException for non-IO related errors.