Create a new line in Java's FileWriter

Question

I have coded the following FileWriter:

try {
    FileWriter writer = new FileWriter(new File("file.txt"), false);

    String sizeX = jTextField1.getText();
    String sizeY = jTextField2.getText();
    writer.write(sizeX);
    writer.write(sizeY);

    writer.flush();
    writer.close();
} catch (IOException ex) {}

Now I want to insert a new line, just like you would do it with \n normally, but it doesn't seem to work.

What can be done to solve this?

Thank you.

Bybee

writer.write("\n"); – Hulky

but it doesn't seem to work can you post results you get? – Ravishment

If I try the "\n" method, there's nothing... just 1254 (12 for sizeX, 54 for sizeY)... – Bybee

@lukulus could you try writer.write("\r\n"); or better writer.write(System.lineSeparator())? – Ravishment

Do not edit the question to invalidate existing answers. – Liddle

Answer 1

If you want to get new line characters used in current OS like \r\n for Windows, you can get them by

• System.getProperty("line.separator");
• since Java7 System.lineSeparator()
• or as mentioned by Stewart generate them via String.format("%n");

---

You can also use PrintStream and its println method which will add OS dependent line separator at the end of your string automatically

PrintStream fileStream = new PrintStream(new File("file.txt"));
fileStream.println("your data");
//         ^^^^^^^ will add OS line separator after data 

(BTW System.out is also instance of PrintStream).

Ravishment

Answer 2

Try System.getProperty( "line.separator" )

   writer.write(System.getProperty( "line.separator" ));

Forth

Answer 3

Try wrapping your FileWriter in a BufferedWriter:

BufferedWriter bw = new BufferedWriter(writer);
bw.newLine();

Javadocs for BufferedWriter here.

Davies

Answer 4

Try:

String.format("%n");

See this question for more details.

Davies

Answer 5

If you mean use the same code but add a new line so that when you add something to the file it will be on a new line. You can simply use BufferedWriter's newLine().
Here I have Improved you code also: NumberFormatException was unnecessary as nothing was being cast to a number data type, saving variables to use once also was.

try {
    BufferedWriter writer = new BufferedWriter(new FileWriter("file.txt"));
        writer.write(jTextField1.getText());
        writer.write(jTextField2.getText());
        writer.newLine();
        writer.flush();
        writer.close();
} catch (IOException ex) {
    System.out.println("File could not be created");
}

Figurant

Answer 6

Since 1.8, I thought this might be an additional solution worth adding to the responses:

Path java.nio.file.Files.write(Path path, Iterable lines, OpenOption... options) throws IOException

StringBuilder sb = new StringBuilder();
sb.append(jTextField1.getText());
sb.append(jTextField2.getText());
sb.append(System.lineSeparator());
Files.write(Paths.get("file.txt"), sb.toString().getBytes());

If appending to the same file, perhaps use an Append flag with Files.write()

Files.write(Paths.get("file.txt"), sb.toString().getBytes(), StandardOpenOption.APPEND);

Aerostat

Answer 7

Here "\n" is also working fine. But the problem here lies in the text editor(probably notepad). Try to see the output with Wordpad.

Limekiln

Smart one! Worked for me and should work for assignments. However for a project, any of the above highlighted approaches should be used – Miffy

yes, Notepad doesn't work with /n, but WordPad works fine with /n. Or need to use line.separator for Notepad. – Peaked

Answer 8

One can use PrintWriter to wrap the FileWriter, as it has many additional useful methods.

try(PrintWriter pw = new PrintWriter(new FileWriter(new File("file.txt"), false))){
   pw.println();//new line
   pw.print("text");//print without new line
   pw.println(10);//print with new line
   pw.printf("%2.f", 0.567);//print double to 2 decimal places (without new line)
}

Liebfraumilch

Answer 9

I would tackle the problem like this:

    BufferedWriter output;
    output = new BufferedWriter(new FileWriter("file.txt", true));
    String sizeX = jTextField1.getText();
    String sizeY = jTextField2.getText();
    output.append(sizeX);
    output.append(sizeY);
    output.newLine();
    output.close();

The true in the FileWriter constructor allows to append.
The method newLine() is provided by BufferedWriter
Could be ok as solution?

Hitoshi

Answer 10

using simple \n to break line in write file and normal output in java

Tournai

Your answer doesn't add anything to the question, which hasn't been answered already. – Pulmotor