Can OpenCSV ignore trailing commas on records? - csv

Question

A CSV with trailing commas like this:
name, phone
joe, 123-456-7890,
bob, 333-555-6666,
processed like this:
CSVReaderHeaderAware r = new CSVReaderHeaderAware(reader);
Map<String, String> values = r.readMap();
will throw this exception:
java.io.IOException: Error on record number 2: The number of data elements is not the same as the number of header elements
For now I'm stripping commas from input files using sed:
find . -type f -exec sed -i 's/,*\r*$//' {} \;
Is there some easy way to tell OpenCSV to ignore trailing commas?

Answer 1

OpenCSV maintainers commented here. As of OpenCSV v5.1 there is no simple way to accomplish this and pre-processing the file using sed, etc is best for now.

Answer 2

According to link provided in #Andrew's answer it's a malformed CSV input.
But as own maintainer suggests ( here ):
If you know you will always have single-line records, you could
derive a class from CSVReader, override getNextLine() to call
super.getNextLine(), then cut off the trailing comma, and of course,
pass your new reader into opencsv to use in parsing.
In other words, create your own CustomCSVReader and remove the last comma.
Here's an example:
import com.opencsv.CSVReader;
public class CustomCSVReader extends CSVReader {
public CustomCSVReader(Reader reader) {
super(reader);
}
#Override
protected String getNextLine() throws IOException {
String line = super.getNextLine();
if (line == null) {
return null;
}
boolean endsWithComma = line.endsWith(",");
if (endsWithComma) {
return line.substring(0, line.length() - 1);
}
return line;
}
}
The Model Converter using CustomCSVReader
public class CustomCSVParser{
public List<User> convert(String data) {
return new CsvToBeanBuilder<Transaction>(new CustomCSVReader(new StringReader(data)))
.withType(User.class)
.build()
.parse();
}
The Model class
import com.opencsv.bean.CsvBindByName;
public class User {
#CsvBindByName(column = "name")
private String userName;
#CsvBindByName(column = "phone")
private String phoneNumber;
// Constructor, Getters and Setters ommited
}
Test Class
class CustomCSVParserTest {
private CustomCSVParser instance;
#BeforeEach
void setUp() {
instance = new CustomCSVParser();
}
#Test
void csvInput_withCommaInLastLine_mustBeParsed() {
String data = "name, phone
joe, 123-456-7890,
bob, 333-555-6666,";
List<User> result = instance.convert(data);
List<User> expectedResult = Arrays.asList(
new User("joe", "123-456-7890"),
new User("bob", "333-555-6666"));
Assertions.assertArrayEquals(expectedResult.toArray(), result.toArray());
}
}
That's it.