how to fetch and validate csv header in open csv?

I want to fetch header from csv file . If I am not use this skipLines then I will get header at 0 index array . But I want to fetch header directly using HeaderColumnNameMappingStrategy but it will not work with my code.

I also want to validate header column list ( like csv had not allowed to contain extra column)

I had also check this How to validate the csv headers using opencsv but it was not helpful to me.

@SuppressWarnings({ "unchecked", "rawtypes" })
public Map<String, Object> handleStockFileUpload(MultipartFile file, Long customerId) {
    Map<String, Object> responseMap = new HashMap<>();
    responseMap.put("datamap", "");
    responseMap.put("errormap", "");
    responseMap.put("errorkeys", "");

    List<Map<String, Integer>> list = new ArrayList<>();
    List<StockCsvDTO> csvStockList = new ArrayList<>();

    try {
        String fileName = new SimpleDateFormat("yyyy_MM_dd_HHmmss").format(new Date()) + "_" + file.getOriginalFilename();
        responseMap.put("filename", fileName);

        File stockFile = new File(productsUploadFilePath + fileName);
        stockFile.getParentFile().mkdirs();
        FileOutputStream fos = new FileOutputStream(stockFile);
        fos.write(file.getBytes());
        fos.close();


        CsvTransfer csvTransfer = new CsvTransfer();


        ColumnPositionMappingStrategy ms = new ColumnPositionMappingStrategy();
        ms.setType(StockCsv.class);

        Reader reader = Files.newBufferedReader(Paths.get(productsUploadFilePath + fileName));
        CSVReader csvReader =  new CSVReader(reader);

        CsvToBean cb = new CsvToBeanBuilder(reader)
          .withType(StockCsv.class)
          .withMappingStrategy(ms)
          .withSkipLines(1)
          .build();

       csvTransfer.setCsvList(cb.parse());
       reader.close();


       csvStockList = csvTransfer.getCsvList();

    } catch (Exception e) {
        e.printStackTrace();
        responseMap.put("status", "servererror");
    }

     responseMap.put("datamap", csvStockList);

    return responseMap;
}

Solution

Here I was comparing my csvHeader with originalHeader:

List<String> originalHeader = fileUploadUtility.getHeader(new StockCsv());

List<String> invalidHeader = csvHeader.stream().filter(o -> (originalHeader.stream().filter(f -> f.equalsIgnoreCase(o)).count()) < 1).collect(Collectors.toList());
            if(null != invalidHeader && invalidHeader.size() > 0 && invalidHeader.toString().replaceAll("\\[\\]", "").length() > 0) {
                msg = "Invalid column(s) : " + invalidHeader.toString().replace(", ]", "]") + ". Please remove invalid column(s) from file.";
                resultMap.put(1, msg);
            }


 public List<String> getHeader(T pojo) {
    // TODO Auto-generated method stub
    final CustomMappingStrategy<T> mappingStrategy = new CustomMappingStrategy<>();
    mappingStrategy.setType((Class<? extends T>) pojo.getClass());
    String header[] = mappingStrategy.generateHeader();
    List<String> strHeader = Arrays.asList(header);
    return strHeader;
  }