How do I end line when writing to a text file?

Question

I'm writing to a text file but when I look into the file everything is in on line even though I'm adding "\n" in the string in the for-loop. What am I overlooking?

File file = new File(dir.getAbsolutePath() + "\\SavedJavaArithmetic.txt");

FileWriter fileW = new FileWriter(file);
BufferedWriter buffW = new BufferedWriter(fileW);

for (int i = 0; i < list.size(); i++) {
    buffW.write(list.get(i).toString() + "\n");
}
buffW.close();
fileW.close();

The arraylist "list" is already created and filled when the for loop starts.

Why are you iterating over an empty list? That is definitely not what you want — Aluan Haddad, Nov 02 '17 at 03:14
I had just added that line to show that there was an arraylist even though in my full code it is near the beginning and already filled. — biz, Nov 02 '17 at 03:18
Or try: `buffW.write(list.get(i).toString() + System.getProperty("line.separator"));` — DevilsHnd - 退職した, Nov 02 '17 at 04:20

Elliott Frisch · Accepted Answer · 2017-11-02T03:26:02.897

Please program to the List interface. To your question use System.lineSeparator(), because "\n" is not cross-platform (on Windows, the line separator is "\r\n"). Next, File provides two argument constructors. And there is BufferedWriter.newLine() which might look like

List<String> list = new ArrayList<>();
File file = new File(dir.getAbsolutePath(), "SavedJavaArithmetic.txt");

try (FileWriter fileW = new FileWriter(file);
            BufferedWriter buffW = new BufferedWriter(fileW)) {
    for (int i = 0; i < list.size(); i++) {
        buffW.write(list.get(i));
        buffW.newLine();
    }
}

Alternatively, use a PrintWriter (it provides a more natural syntax). And, I would use a for-each loop. Also, in both cases, I would use a try-with-resources to handle the close(s). Putting that all together might look something like,

List<String> list = new ArrayList<>();
// ...
File file = new File(dir.getAbsolutePath(), "SavedJavaArithmetic.txt");
try (PrintWriter pw = new PrintWriter(file)) {
    for (String str : list) {
        pw.println(str);
    }
}

And, in Java 8+, using a Stream with a forEachOrdered like

List<String> list = new ArrayList<>();
File file = new File(dir.getAbsolutePath(), "SavedJavaArithmetic.txt");
try (PrintWriter pw = new PrintWriter(file)) {
    list.stream().forEachOrdered(pw::println);
}

How do I end line when writing to a text file?

1 Answers1