Question

I want to write a simple java program to read in a text file and then write out a new file whenever a blank line is detected. I have seen examples for reading in files but I don’t know how to detect the blank line and output multiple text files.

fileIn.txt:

line1
line2

line3

fileOut1.txt:

line1
line2

fileOut2.txt:

line3

Answer 1

Just in case your file has special characters, maybe you should specify the encoding.

FileInputStream inputStream = new FileInputStream(new File("fileIn.txt"));
InputStreamReader streamReader = new InputStreamReader(inputStream, "UTF-8");
BufferedReader reader = new BufferedReader(streamReader);
int n = 0;
PrintWriter out = new PrintWriter("fileOut" + ++n + ".txt", "UTF-8");
for (String line;(line = reader.readLine()) != null;) {
    if (line.trim().isEmpty()) {
        out.flush();
        out.close();
        out = new PrintWriter("file" + ++n + ".txt", "UTF-8");
    } else {
        out.println(line);
    }
}
out.flush();
out.close();
reader.close();
streamReader.close();
inputStream.close();