Split Java String by New Line

Question

I'm trying to split text in a JTextArea using a regex to split the String by \n However, this does not work and I also tried by \r\n|\r|n and many other combination of regexes. Code:

public void insertUpdate(DocumentEvent e) {
    String split[], docStr = null;
    Document textAreaDoc = (Document)e.getDocument();

    try {
        docStr = textAreaDoc.getText(textAreaDoc.getStartPosition().getOffset(), textAreaDoc.getEndPosition().getOffset());
    } catch (BadLocationException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
    }

    split = docStr.split("\\n");
}

Answer 1

package in.javadomain;

public class JavaSplit {

    public static void main(String[] args) {
        String input = "chennai\nvellore\ncoimbatore\nbangalore\narcot";
        System.out.println("Before split:\n");
        System.out.println(input);

        String[] inputSplitNewLine = input.split("\\n");
        System.out.println("\n After split:\n");
        for(int i=0; i<inputSplitNewLine.length; i++){
            System.out.println(inputSplitNewLine[i]);
        }
    }

}

Answer 2

For preserving empty lines from getting squashed use:

String lines[] = String.split("\\r?\\n", -1);

Answer 3

All answers given here actually do not respect Javas definition of new lines as given in e.g. BufferedReader#readline. Java is accepting \n, \r and \r\n as new line. Some of the answers match multiple empty lines or malformed files. E..g. <sometext>\n\r\n<someothertext> when using [\r\n]+would result in two lines.

String lines[] = string.split("(\r\n|\r|\n)", -1);

In contrast, the answer above has the following properties:

• it complies with Javas definition of a new line such as e.g. the BufferedReader is using it
• it does not match multiple new lines
• it does not remove trailing empty lines

Answer 4

split method is using regex (regular expressions). Since Java 8 regex supports \R which represents (from documentation of Pattern class):

Linebreak matcher
\R         Any Unicode linebreak sequence, is equivalent to \u000D\u000A|[\u000A\u000B\u000C\u000D\u0085\u2028\u2029]

So we can use it to match:

• \u000D\000A -> \r\n pair
• \u000A -> line feed (\n)
• \u000B -> line tabulation (DO NOT confuse with character tabulation \t which is \u0009)
• \u000C -> form feed (\f)
• \u000D -> carriage return (\r)
• \u0085 -> next line (NEL)
• \u2028 -> line separator
• \u2029 -> paragraph separator

As you see \r\n is placed at start of regex which ensures that regex will try to match this pair first, and only if that match fails it will try to match single character line separators.

---

So if you want to split on line separator use split("\\R").

If you don't want to remove from resulting array trailing empty strings "" use split(regex, limit) with negative limit parameter like split("\\R", -1).

If you want to treat one or more continues empty lines as single delimiter use split("\\R+").

Answer 5

String.split(System.getProperty("line.separator"));

This should be system independent

Answer 6

String lines[] =String.split( System.lineSeparator())