Modifying Text File By line

[leonardo ginting]

Hi guys
how could i modify text file java by line i.e

i have 4 line and each line i have a words

aaa
bbb
ccc
ddd

and i would like to modify line number 2 which is 'bbb'
being rrrr

and how could i do that?

here is my code

try {

            String content = "aaa \n";
            String content2 = "bbb";
            String content3 = "ccc";
            String content4 = "ddd";

            File file = new File("/home/leonardo/Desktop/filename.txt");
            FileWriter fw = new FileWriter(file.getAbsoluteFile());

            BufferedWriter bw = new BufferedWriter(fw);
            bw.write(content);
            bw.write(content2);
            bw.write(content3);
            bw.write(content4);
           bw.close();
            
            FileReader fr = new FileReader(file);
            LineNumberReader lnr = new LineNumberReader(fr);
            BufferedReader br = new BufferedReader(fr);
            PrintWriter pw = new PrintWriter(fw);


            // if file doesnt exists, then create it
            if (!file.exists()) {
                file.createNewFile();
            }
           
            String lineToRemove = "12";
            String old;

            int linenumber = 0;

            String trimmedLine = "";
            while (( old= lnr.readLine()) != null) {

                trimmedLine = old.trim();
                if (trimmedLine.equals(lineToRemove)) {
                    
                    continue;
                }

                bw.write(old);
                linenumber++;
            }
            System.out.println("Total number of lines : " + linenumber);

            lnr.close();
            System.out.println("Done");

        } catch (IOException e) {

            e.printStackTrace();

        }

    }

if i do this code i got an error because i've closed bw

the error is

java.io.IOException: Stream closed
	at java.io.BufferedWriter.ensureOpen(BufferedWriter.java:115)
	at java.io.BufferedWriter.write(BufferedWriter.java:220)
	at java.io.Writer.write(Writer.java:157)
	at filejava.FileJava.main(FileJava.java:64)

thanks guys
any help would be appreciate

BF
Leonardo

[Ulf Dittmer]

You can't read and write a file at the same time. You'll need to write to a different file than the one you're reading. After you're done, you can delete the former and rename the latter.

[leonardo ginting]

Ulf Dittmer wrote:You can't read and write a file at the same time. You'll need to write to a different file than the one you're reading. After you're done, you can delete the former and rename the latter.

ahhh ok thanks ulf you have given me enlightment thank you so much ulf,,
it means i have to create a new class to for modify the text that ive created right?


BF
Leonardo

[Ulf Dittmer]

You don't need another class. And there isn't really a "modifying". Just read from one file and write to another.