Buffered Reader readLine() with Empty lines

Walt picture Walt · Aug 20, 2010 · Viewed 49.6k times · Source

I am using buffered reader to grab a line at a time from a text file. I am trying to also get the line number from the text file using a tracking integer. Unfortunately BufferedReader is skipping empty lines (ones with just /n or the carriage return).

Is there a better way to solve this? Would using scanner work?

Example code:

int lineNumber = 0;
while ((s = br.readLine()) != null) {
    this.charSequence.add(s, ++lineNumber);
}

Answer

polygenelubricants picture polygenelubricants · Aug 20, 2010

I could not reproduce your claim that BufferedReader skips empty lines; it should NOT have.

Here are snippets to show that empty lines aren't just skipped.

java.io.BufferedReader

    String text = "line1\n\n\nline4";
    BufferedReader br = new BufferedReader(new StringReader(text));
    String line;
    int lineNumber = 0;
    while ((line = br.readLine()) != null) {
        System.out.printf("%04d: %s%n", ++lineNumber, line);
    }

java.io.LineNumberReader

    String text = "line1\n\n\nline4";
    LineNumberReader lnr = new LineNumberReader(new StringReader(text));
    String line;
    while ((line = lnr.readLine()) != null) {
        System.out.printf("%04d: %s%n", lnr.getLineNumber(), line);
    }

java.util.Scanner

    String text = "line1\n\n\nline4";
    Scanner sc = new Scanner(text);
    int lineNumber = 0;
    while (sc.hasNextLine()) {
        System.out.printf("%04d: %s%n", ++lineNumber, sc.nextLine());
    }

The output for any of the above snippets is:

0001: line1
0002: 
0003: 
0004: line4

Related questions