Get CSV file header using apache commons

Question

I have been looking for the past 2 hours for a solution to my problem in vain. I'am trying to read a CSV File using Apache commons ,I am able to read the whole file but my problem is how to extract only the header of the CSV in an array?

Answer 1

By default, first record read by CSVParser will always be a header record, eg in the below example:

CSVFormat csvFileFormat = CSVFormat.DEFAULT.withHeader(FILE_HEADER_MAPPING);
FileReader fileReader = new FileReader("file");
CSVParser csvFileParser = new CSVParser(fileReader, csvFileFormat);
List csvRecords = csvFileParser.getRecords();

csvRecords.get(0) will return the header record.

Answer 2

I looked everywhere and even the solution above didn't work. For anyone else with this issue, this does.

Iterable<CSVRecord> records;
Reader in = new FileReader(fileLocation);
records = CSVFormat.EXCEL.withHeader().withSkipHeaderRecord(false).parse(in);
Set<String> headers = records.iterator().next().toMap().keySet();

Note that your use of .next() has consumed one row of the CSV.

Answer 3

BufferedReader br = new BufferedReader(new FileReader(filename));

CSVParser parser = CSVParser.parse(br, CSVFormat.EXCEL.withFirstRecordAsHeader());

List<String> headers = parser.getHeaderNames();

This worked for me. The last line is what you need, extracts the headers found by the parser into a List of Strings.

Answer 4

In Kotlin:

val reader = File(path).bufferedReader()
val records = CSVFormat.DEFAULT.withFirstRecordAsHeader()
    .withIgnoreHeaderCase()
    .withTrim()
    .parse(reader)

println(records.headerNames)