Merge CSV files into a single file with no repeated headers

Question

I have some CSV files with the same column headers. For example

File A

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

File B

Answer 1

Here is an example:

public static void main(String[] args) throws IOException {
    List paths = Arrays.asList(Paths.get("c:/temp/file1.csv"), Paths.get("c:/temp/file2.csv"));
    List mergedLines = getMergedLines(paths);
    Path target = Paths.get("c:/temp/merged.csv");
    Files.write(target, mergedLines, Charset.forName("UTF-8"));
}

private static List getMergedLines(List paths) throws IOException {
    List mergedLines = new ArrayList<> ();
    for (Path p : paths){
        List lines = Files.readAllLines(p, Charset.forName("UTF-8"));
        if (!lines.isEmpty()) {
            if (mergedLines.isEmpty()) {
                mergedLines.add(lines.get(0)); //add header only once
            }
            mergedLines.addAll(lines.subList(1, lines.size()));
        }
    }
    return mergedLines;
}