Vfrdtyky

Student.txt

1,Giannis,Oreos,Man

2,Maria,Karra,Woman

3,Maria,Oaka,Woman

After run my code I take this:

Student.txt

1,Giannis,Oreos,Man

2,Maria,Karra,Woman

3,Maria,Oaka,Woman,2,3,1,3,4,6

But I want, if I search for ID=2 go to 2nd line and put the numbers, like that:

Student.txt

1,Giannis,Oreos,Man

2,Maria,Karra,Woman,2,3,1,3,4,6

3,Maria,Oaka,Woman

Code:

@FXML 

TextField ID1,glossa,math,fis,xim,prog,gym;



@FXML

public void UseAddLesson() throws IOException{

    Scanner x = new Scanner("src/inware/students.txt");



    FileWriter fW = new FileWriter("src/inware/students.txt",true);

    BufferedWriter bW = new BufferedWriter(fW);



    boolean found= false;



    while(!found){

        String line = x.nextLine();

        if(line.contains(ID1.getText())){

            bW.write(","+glossa.getText()+",");

            bW.write(math.getText()+",");

            bW.write(fis.getText()+",");

            bW.write(xim.getText()+",");

            bW.write(prog.getText()+",");

            bW.write(gym.getText());

            System.out.println(line);

            found= true;

        }

    }

    bW.close();

    fW.close();

    x.close();

}

Do not attempt to read/write to the same file at the same time. You also cannot append/overwrite the structure of a text file requires all the text following the inserting point to be written at a different position.

I recommend creating a temporary file and replacing the old file with the new one you're done:

@FXML

public void UseAddLesson() throws IOException{

    String searchText = ID1.getText();

    Path p = Paths.get("src", "inware", "students.txt");

    Path tempFile = Files.createTempFile(p.getParent(), "studentsTemp", ".txt");

    try (BufferedReader reader = Files.newBufferedReader(p);

            BufferedWriter writer = Files.newBufferedWriter(tempFile)) {

        String line;



        // copy everything until the id is found

        while ((line = reader.readLine()) != null) {

            writer.write(line);

            if (line.contains(searchText)) {

                writer.write(","+glossa.getText()+",");

                writer.write(math.getText()+",");

                writer.write(fis.getText()+",");

                writer.write(xim.getText()+",");

                writer.write(prog.getText()+",");

                writer.write(gym.getText());

                break;

            }

            writer.newLine();

        }



        // copy remaining lines

        if (line != null) {

            writer.newLine();

            while ((line = reader.readLine()) != null) {

                writer.write(line);

                writer.newLine();

            }

        }

    }



    // copy new file & delete temporary file

    Files.copy(tempFile, p, StandardCopyOption.REPLACE_EXISTING);

    Files.delete(tempFile);

}

Note: If you distribute the app, probably the src directory will become unavailable.