我想从csv文件获取标头。如果我不使用此skipLines，则将在0索引数组处获得标头。但是我想直接使用HeaderColumnNameMappingStrategy获取标头，但不适用于我的代码。
我还想验证标题列列表（例如csv不允许包含额外的列）
我也检查了此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;
}
答案 0 :(得分：1)
我找到了以下解决方案：
public static class HollywoodActor {
@CsvBindByName //no 'column' value, same as property name
private int id;
@CsvBindByName(column = "First Name")
private String firstName;
@CsvBindByName(column = "Last Name")
private String lastName;
// getter / setter
}
public class CsvParser {
public <T> ParseResult<T> parseByPropertyNames(Reader csvReader, Class<T> beanClass) throws IOException {
if (!hasCsvBindByNameAnnotatedProperty(beanClass)) {
throw new IllegalArgumentException(
format("At least one of bean class=%s properties should be annotated with @%s", beanClass.getName(),
CsvBindByName.class.getName()));
}
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);
}
...
private boolean hasCsvBindByNameAnnotatedProperty(Class beanClass) {
for (Field field : beanClass.getDeclaredFields()) {
if (field.getAnnotation(CsvBindByName.class) != null) {
return true;
}
}
for(PropertyDescriptor d : PropertyUtils.getPropertyDescriptors(beanClass)) {
if (d.getReadMethod() != null && d.getReadMethod().getAnnotation(CsvBindByName.class) != null) {
return true;
}
if (d.getWriteMethod() != null && d.getWriteMethod().getAnnotation(CsvBindByName.class) != null) {
return true;
}
}
return false;
}
}
也不要忘记添加公共类ParseResult
public class ParseResult <T> {
private final String[] headers;
private final List<T> lines;
// all-args constructor & getters
}
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)));
希望有帮助！
答案 1 :(得分：0)
这里是当前问题的替代方法。首先，定义您希望标题显示的内容。例如：
public static final ArrayList<String> fileFormat = new ArrayList<>
(Arrays.asList("Values1", "Values2", "Values3", "Values4"));
现在，编写一个返回自定义错误（如果存在）的方法：
public String validateCsvFileDetails(MultipartFile file, Set<String> requiredHeadersArray) {
Set<String> errors = new HashSet<>();
try {
InputStream stream = file.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(stream));
String headerLine = reader.readLine();
if (Objects.isNull(headerLine))
return "The file has no headers, please ensure it has the correct upload format";
List<String> headersInFileList;
String[] headersInFileArray;
if (headerLine.contains(",")) {
headersInFileArray = StringUtils.split(headerLine, ",");
headersInFileList = Arrays.asList(headersInFileArray);
} else//the headerline has only one headerfield
{
headersInFileList = Collections.singletonList(headerLine);
}
for (String header : requiredHeadersArray) {
if (!headersInFileList.contains(header))
errors.add("The file has the wrong header format, please ensure " + header + " header is present");
}
//if there are errors, return it
if (!errors.isEmpty())
return sysUtils.getStringFromSet(errors);
//Ensure the csv file actually has values after the header, but don't read beyond the first line
String line;
int counter = 0;
while ((line = reader.readLine()) != null) {
counter++;
if (counter > 0)
break;
}
//if line is null return validation error
if (Objects.isNull(line))
return "Cannot upload empty file";
} catch (Exception e) {
logger.error(new Object() {
}.getClass().getEnclosingMethod().getName(), e);
return "System Error";
}
return null;
}
现在，您可以按以下方式验证文件头：
String errors = validateCsvFileDetails(file, new HashSet<>(fileFormat));
if (errors != null)
return error
//procceed
答案 2 :(得分：0)
在这里，我将csvHeader与originalHeader进行比较：
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;
}
答案 3 :(得分：0)
尝试使用 captureHeader 作为预过滤器： ...
private class CustomHeaderColumnNameMappingStrategy<T> extends HeaderColumnNameMappingStrategy {
private String[] expectedHeadersOrdered = {"Column1", "Column2", "Column3", "Column4", "Column5"};
@Override
public void captureHeader(CSVReader reader) throws IOException, CsvRequiredFieldEmptyException {
String[] actualCsvHeaders = reader.peek();
String actualHeader, expectedHeader;
if (expectedHeadersOrdered.length > actualCsvHeaders.length) {
throw new CsvRequiredFieldEmptyException("Missing header column.");
} else if (expectedHeadersOrdered.length < actualCsvHeaders.length) {
throw new IOException("Unexpected extra header column.");
}
// Enforce strict column ordering with index
// TODO: you might want to employ simple hashMap, List, set, etc. as needed
for (int i=0; i<actualCsvHeaders.length; i++) {
actualHeader = actualCsvHeaders[i];
expectedHeader = expectedHeadersOrdered[i];
if ( ! expectedHeader.equals(actualHeader) ) {
throw new IOException("Header columns mismatch in ordering.");
}
}
super.captureHeader(reader); // Back to default processing if the headers include ordering are as expected
}
}
CustomHeaderColumnNameMappingStrategy yourMappingStrategy = new CustomHeaderColumnNameMappingStrategy<YourPOJO>();
ourMappingStrategy.setType(YourPOJO.class);
try {
pojosFromCsv = new CsvToBeanBuilder<YourPOJO>(new FileReader(csvFile))
.withType(YourPOJO.class)
.withMappingStrategy(yourMappingStrategy)
.build();
pojosFromCsv.stream();
}