Separate a .txt file by empty line and copy into another .txt file

Question

I've been searching the web but to no avail.

My problem is that I have one log text file that contains text like

2014-03-04 08:28:45 1WKkiT-0008Qr-M9 Message received from xx (1.2.3.41) T="q"
2014-03-04 08:28:45 1WKkiT-0008Qr-M9 Message was delivered to xxxH=xxx[11.11.11.1] C="250 Queued (0.000 seconds)"
2014-03-04 08:28:45 1WKkiT-0008Qr-M9 Completed

2014-03-04 08:28:45 1WKkiT-0008Qr-M9 DKIM: d=x=relaxed/relaxed a=rsa-sha1 t=1393921721 [verification succeeded]
2014-03-04 08:29:12 1WKkit-0005cD-UZ Message received from x x T="x"
2014-03-04 08:29:12 1WKkit-0005cD-UZ Message was delivered to xxxH=x xxx C="250 Queued (0.000 seconds)"
2014-03-04 08:29:12 1WKkit-0005cD-UZ Completed

The actual file is much larger.

What I would like is to read this whole file block by block (the blank line as a separator) and then write each block to another pre-made text file as I do so.

I am currently using a BufferedReader and BufferedWriter but am not married to the idea of using these.

Any help would be greatly appreciated, thanks

"but am not married to the idea of using these".. lol.. Then get married to them by googling them. — AJ., Mar 07 '14 at 13:28
`if ("\n".equals(bufferReaderObject.readLine())){create new file}` — Seega, Mar 07 '14 at 13:31

Abiel Paltao · Accepted Answer · 2014-03-07T13:53:51.980

2

I think this is what you want:

BufferedReader reader = new BufferedReader(new FileReader("text.txt"));
    String line = null;
    ArrayList<String> block = new ArrayList<String>();
    String tmp="";
    while ((line = reader.readLine()) != null) {
        if(line.equals(""))
        {
            block.add(tmp);
            tmp="";
        }
        else
        {
            tmp = tmp + line;
        }
    }
    block.add(tmp);
            reader.close();
    System.out.println(block.size());
    System.out.println(block.toString());

Just run a for loop to copy that to another text file.

Replace

tmp = tmp + line";

with

tmp = tmp + line+"\n";

if you want your string in the same format with the source file

edited Mar 07 '14 at 13:53

answered Mar 07 '14 at 13:32

Abiel Paltao

315
2
12

Oh yes. Totally forgot about that. Updated the code :D – Abiel Paltao Mar 07 '14 at 13:54
Just wrote it to the other there and the line "tmp = tmp +line+\n" dose not seem to separate each word, instead all the arraylist is wrote on one line – Sean O'Riordan Mar 07 '14 at 15:46

score 2 · Answer 2 · answered Mar 07 '14 at 13:45

Here's a solution using a StringBuilder and a simple loop. Feel free to adjust it for your own needs!

public List<String> extractBlocks(File file) throws IOException {
    BufferedReader reader = new BufferedReader(new FileReader(file));

    String line;
    StringBuilder block = new StringBuilder();
    List<String> blocks = new ArrayList<String>();
    while ((line = reader.readLine()) != null) {
        if (line.isEmpty()) {
            blocks.add(block.toString());
            block = new StringBuilder();
        } else {
            block.append(line);
        }
    }
    blocks.add(block.toString());

    reader.close();

    return blocks;
}

Separate a .txt file by empty line and copy into another .txt file

2 Answers2