Java: How read a File line by line by ignoring “\\n”

Question

I'm trying to read a tab separated text file line per line. The lines are separated by using carriage return ("\r\n") and LineFeed (\"n") is allowed within in tab separated text fields.

Since I want to read the File Line per Line, I want my programm to ignore a standalone "\n". Unfortunately, BufferedReader uses both possibilities to separate the lines. How can I modify my code, in order to ignore the standalone "\n"?

try 
{
    BufferedReader in = new BufferedReader(new FileReader(flatFile));
    String line = null;
    while ((line = in.readLine()) != null) 
    {
        String cells[] = line.split("\t");                          
        System.out.println(cells.length);
        System.out.println(line);
    }
    in.close();
} 
catch (IOException e) 
{
    e.printStackTrace();
}

Answer 1

Use a java.util.Scanner.

Scanner scanner = new Scanner(new File(flatFile));
scanner.useDelimiter("\r\n");
while (scanner.hasNext()) {
    String line = scanner.next();
    String cells[] = line.split("\t");                          
    System.out.println(cells.length);
    System.out.println(line);
}

Answer 2

You could simply make it skip empty lines:

while ((line = in.readLine()) != null) {
    // Skip lines that are empty or only contain whitespace
    if (line.trim().isEmpty()) {
        continue;
    }

    String[] cells = line.split("\t");
    System.out.println(cells.length);
    System.out.println(line);
}

Answer 3

You can use FileUtils.readLines methods from apache commons-io.

Advantage of using it is that you don't have to care about opening and closing file. It is handled for you.