I am using Springboot + OpenCSV to parse a CSV with 120 columns (sample 1). I upload the file process each rows and in case of error, return a similar CSV (say errorCSV). This errorCSV will have only errored out rows with 120 original columns and 3 additional columns for details on what went wrong. Sample Error file 2
I have used annotation based processing and beans are populating fine. But I need to get header names in the order they appear in the csv. This particular part is quite challenging. Then capture exception and original data during parsing. The two together can later be used in writing CSV.
CSVReaderHeaderAware headerReader;
headerReader = new CSVReaderHeaderAware(reader);
try {
header = headerReader.readMap().keySet();
} catch (CsvValidationException e) {
e.printStackTrace();
}
However the header order is jumbled and there is no way to get header index. The reason being CSVReaderHeaderAware internally uses a HashMap. In order to solve this I built my custom class. It is a replica of CSVReaderHeaderAware 3 except that I used LinkedHashMap
public class CSVReaderHeaderOrderAware extends CSVReader {
private final Map<String, Integer> headerIndex = new LinkedHashMap<>();
}
....
// This code cannot be done with a stream and Collectors.toMap()
// because Map.merge() does not play well with null values. Some
// implementations throw a NullPointerException, others simply remove
// the key from the map.
Map<String, String> resultMap = new LinkedHashMap<>(headerIndex.size()*2);
It does the job however wanted to check if this is the best way out or can you think of a better way to get header names and failed values back and write in a csv.
I referred to following links but couldn't get much help How to read from particular header in opencsv?
