将CSV文件合并为一个文件，没有重复的标题

Question

我有一些具有相同列标题的CSV文件。例如

文件A

header1,header2,header3
one,two,three
four,five,six

文件B

header1,header2,header3
seven,eight,nine
ten,eleven,twelve

我想将其合并，以便将数据合并到一个文件中，文件头位于顶部，但其他任何地方都没有文件头。

header1,header2,header3
one,two,three
four,five,six
seven,eight,nine
ten,eleven,twelve

什么是实现此目标的好方法？

Answer 1

这应该工作。它检查要合并的文件是否具有匹配的头。否则将引发异常。异常处理（关闭流等）已作为练习。

String[] headers = null;
String firstFile = "/path/to/firstFile.dat";
Scanner scanner = new Scanner(new File(firstFile));

if (scanner.hasNextLine())
    headers[] = scanner.nextLine().split(",");

scanner.close();

Iterator<File> iterFiles = listOfFilesToBeMerged.iterator();
BufferedWriter writer = new BufferedWriter(new FileWriter(firstFile, true));

while (iterFiles.hasNext()) {
  File nextFile = iterFiles.next();
  BufferedReader reader = new BufferedReader(new FileReader(nextFile));

  String line = null;
  String[] firstLine = null;
  if ((line = reader.readLine()) != null)
    firstLine = line.split(",");

  if (!Arrays.equals (headers, firstLine))
    throw new FileMergeException("Header mis-match between CSV files: '" +
              firstFile + "' and '" + nextFile.getAbsolutePath());

  while ((line = reader.readLine()) != null) {
    writer.write(line);
    writer.newLine();
  }

  reader.close();
}
writer.close();