How to replace a line in a file through jtextfield?
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Thread: How to replace a line in a file through jtextfield?

  1. #1
    Join Date
    Jan 2013
    Posts
    1

    How to replace a line in a file through jtextfield?

    This is a program that allows the user to search for an item and then the program splits the items and stores them in 4 different textfields. However, below is a method for updating the retrieved items back to the file. The problem is whenever the user clicks on the update button, the line does update successfully, but the other lines in the file are deleted!

    Iam using an arraylist to store the searched item and also temporary file to write the item and then renaming it.

    Can someone help me please. Thanks in advance!

    Code:
    file.txt
    
    ramal hotel1  10 uk
    
    bren  hotel2  20 france
    
    gil   hotel3  30 china

    Code:
    //Update to file
    button9.addActionListener(new ActionListener(){
    public  void actionPerformed(ActionEvent ae){
    
        try {
    
        String stringSearch = textfield1.getText();
    
        File filetemp = File.createTempFile("TempFileName", ".tmp", new File("/"));
        BufferedWriter writer = new BufferedWriter(new FileWriter(filetemp));
        File file = new File("file.txt");
        BufferedReader bf = new BufferedReader(new FileReader(file));
    
    
        int linecount = 0;
                  String line;
    
        ArrayList<String> list = new ArrayList<String>();
        while (( line = bf.readLine()) != null){
        list.add(line);
        linecount++;
    
    
        int indexfound = line.indexOf(stringSearch);
    
        if (indexfound > -1) {
    
        String a = textfield1.getText();
        String b = textfield2.getText();
        String c = textfield3.getText();
        String d = textfield4.getText();
    
    
    
    
        String[] word = line.split("\t");
        String firstword = word[0];
        String secondword = word[1];
        String thirdword = word[2];
        String fourthword = word[3];
    
    
    
    
        writer.write(line.replace("\t", "\t").replace(firstword, b).replace(secondword, c).replace(thirdword, d));
        writer.flush();
    
        }
    
        writer.newLine();
        }
        writer.close();
        bf.close();
        filetemp.renameTo(file);
        filetemp.deleteOnExit();
    
    
        FileChannel src = new FileInputStream(filetemp).getChannel();
        FileChannel dest = new FileOutputStream(file).getChannel();
        dest.transferFrom(src, 0, src.size());
    
    
    
        }catch (IOException e) {
    
        System.out.println("IO Error Occurred: " + e.toString());
    
        }
    
    }
    });

  2. #2
    Join Date
    May 2006
    Location
    UK
    Posts
    4,474

    Re: How to replace a line in a file through jtextfield?

    Your program is only outputting the values in the text fields and so the rest of the file will be lost. You need to write out the values for the whole file.
    Posting code? Use code tags like this: [code]...Your code here...[/code]
    Click here for examples of Java Code

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