java - 如何在打开的 csv 中获取并验证 csv header ？

Question

我想从 csv 文件中获取标题。如果我不使用这个skipLines，那么我将在0索引数组处获得标题。但我想使用 HeaderColumnNameMappingStrategy 直接获取标题，但它不适用于我的代码。

我还想验证标题列列表(例如 csv 不允许包含额外的列)

我还检查了这个How to validate the csv headers using opencsv但这对我没有帮助。

@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;
}

Answer 1

我找到了以下解决方案:

1. 将 @CsvBindByName 与 HeaderColumnNameMappingStrategy 结合使用，例如使用 @CsvBindByName 注释您的 bean 属性:

    public static class HollywoodActor {
        private int id;
        @CsvBindByName(column = "First Name")
        private String firstName;
        @CsvBindByName(column = "Last Name")
        private String lastName;
    // getter / setter
    }

添加如下方法:

    public class CsvParser {

        public <T> ParseResult<T> parseByPropertyNames(Reader csvReader, Class<T> beanClass) throws IOException {
            CSVReader reader = new CSVReaderBuilder(csvReader).withCSVParser(new 
 CSVParserBuilder().build()).build();
            CsvToBean<T> bean = new CsvToBean();
            HeaderColumnNameMappingStrategy<T> mappingStrategy = new HeaderColumnNameMappingStrategy();
            mappingStrategy.setType(beanClass);
            bean.setMappingStrategy(mappingStrategy);
            bean.setCsvReader(reader);
            List<T> beans = bean.parse();
            return new CsvParseResult<>(mappingStrategy.generateHeader(), beans);
        }

并且不要忘记添加公共(public)类 ParseResult

    public class ParseResult <T> {
      private final String[] headers;
      private final List<T> lines;
      // all-args constructor & getters
    }

在您的代码中使用它们:

    String csv = "Id,First Name,Last Name\n" + "1, \"Johnny\", \"Depp\"\n" + "2, \"Al\", \"Pacino\"";
    CsvParseResult<HollywoodActor> parseResult = parser
                .parseByPropertyNames(new InputStreamReader(new ByteArrayInputStream(csv.getBytes(StandardCharsets.UTF_8), HollywoodActor.class)));

从 ParseResult.headers 中，您可以获取 .csv 文件中的实际 header 。只需将它们与预期进行比较即可。

希望有帮助!