Question

I need to get certain line from text component with multiline support. So it either JTextArea or JTextPane.

How to get line 1 , 2 or .. etc? For example get line3 from text below

line1
line2
line3
line4

And is it possible to set another value for some line? For examp. set lineNew instead of line2

line1
lineNew
line3
line4

Is there any way?

Answer 1

To grab the text in a JTextComponent, use the getText() method which will return a String.

Then to get the lines, split the string on \n.

JTextArea txt = new JTextArea("line1\nline2\nline3\nline4");
String s = txt.getText();
String[] lines = s.split("\n");
// now to access the second line, use lines[1]

Now if you want to modify the text, you can use the setText(String) method.

txt.setText("something else");

There are also a few other methods that you can use to change the text like insert(String,int), append(String), and replaceRange(String,int,int). All of this is documented in the javadocs.