Using both CSVListReader and CSVBeanreader in superCSV - csv

Question

I want to read different CSV files which have all a fixed column number but 2 different files have 2 different column numbers. All the files have a headerline.
So I first use a CSVListReader to get the header and the column numbers and then construct the cell processors and the a CSV BeanReader to map the actual lines to POJO.
I tried first to make it work with passing InputStreamReaders to the superCsv readers constructors and it doesn't work. Works fine however with FileReaders or BufferedReaders.
Is it a bug or it just does not make sense to use InputStremReaders in this situation?
Here is the working code example
CsvListReader listReader = null;
FileReader file = null;
BufferedReader b = null;
try {
file = new FileReader(linkToFile);
b = new BufferedReader(file);
listReader = new CsvListReader(b,
CsvPreference.STANDARD_PREFERENCE);
csvHeader = listReader.getHeader(true);
} catch (IOException e) {
logger.info("Did not manage to get the Csv Header", e);
try {
listReader.close();
file.close();
} catch (IOException e1) {
logger.info("Problem trying to close the readers", e1);
return;
}
}
try {
file = new FileReader(linkToFile);
b = new BufferedReader(file);
beanReader = new CsvBeanReader(b,
CsvPreference.STANDARD_PREFERENCE);
beanReader.getHeader(false);
extractCSV(beanReader, csvHeader);
catch (IOException e) {
logger.info("Did not manage to get a working CsvBeanReader.", e);
try {
beanReader.close();
listReader.close();
file.close();
} catch (IOException e1) {
logger.info("Problem trying to close the readers", e1);
}
return;
}
Thanks in advance

Answer 1

As per Hound Doc Comments, the reason of the mess up was in a bad management of closing the different readers.
Below is the working code using input stream readers
// Reading the Header. A CsvListReader object is used here as it can
// read a variable number of columns in the first line (see
// http://supercsv.sourceforge.net/readers.html)
CsvListReader listReader = null;
InputStreamReader b = null;
try {
b = new InputStreamReader(new BufferedInputStream(new FileInputStream(linkToFile)));
listReader = new CsvListReader(b, CsvPreference.STANDARD_PREFERENCE);
csvHeader = listReader.getHeader(true);
} catch (IOException e) {
logger.info("Did not manage to get the Csv Header", e);
} finally {
try {
listReader.close();
} catch (IOException e1) {
logger.info("Problem trying to close the readers", e1);
return;
}
}
// Using the CSV bean reader to read the file. Now we know the number of
// columns
// A CsvBeanReader object is the choice to extract easier to POJO
// structure
CsvBeanReader beanReader = null;
try {
b = new InputStreamReader(new BufferedInputStream(new FileInputStream(linkToFile)));
beanReader = new CsvBeanReader(b, CsvPreference.STANDARD_PREFERENCE);
// beanReader starts reading from line 2 (see above)
// it is as if we would be reading a file without a header
beanReader.getHeader(false);
extractCSVContacts(beanReader, csvHeader);
} catch (IOException e) {
logger.info("Did not manage to get a working CsvBeanReader.", e);
return;
}
finally {
try {
beanReader.close();
} catch (IOException e1) {
logger.info("Problem trying to close the readers", e1);
}
}