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Thread: Reading a file with bufferedreader

  1. #1
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    Default Reading a file with bufferedreader

    I can open a file and have it's contents read and printed out on the compiler, so I atleast know that it is reading the file. What I am trying to do though, is to set what is being read, into a JTextArea of a memopad that I created. I just can't get it to work.

    This is my textarea:

    private JTextArea display = new JTextArea();
    ]

    This is my method to open a file:

    private void open()
    {
      String file = JOptionPane.showInputDialog("Please eneter a file name");
      if(file.equals("") || file.length()==0)
     JOptionPane.showMessageDialog(null, "No file selected. Please enter a file name.");
     String text;
         try
            {
              in = new BufferedReader(new FileReader(file));
     
              while((text=in.readLine())!=null)
                {
                   System.out.println(text);//just to make sure it is reading
                 }
     
               display.setText(text);
               in.close();
           }
     
        catch(FileNotFoundException fnfe)
          {
            JOptionPane.showMessageDialog(null, "Error opening file. File Not Found.");
          }
       catch(IOException e)
        {
          JOptionPane.showMessageDialog(null, "Error reading file.");
        }
     
     
    }


  2. #2
    Super Moderator helloworld922's Avatar
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    Default Re: Reading a file with bufferedreader

    Set text replaces all text in the textbox with the given string. You're assigning text to whatever is being read from the file, so when you're done reading, text will always contain null.

    Then, you're setting the text of the textbox to null.

    Instead, you need to concatenate everything you read into one string (preferably a StringBuilder, these are well suited for this type of situation), then set the text of the textbox using this.

  3. The Following User Says Thank You to helloworld922 For This Useful Post:

    ppata (November 20th, 2010)

  4. #3
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    Default Re: Reading a file with bufferedreader

    Thanks! This is what I came up with
    try
     {
      in = new BufferedReader(new FileReader(file));
     String read=in.readLine();
     String text=new String();
     
    while((read=in.readLine())!=null)
     {
       text=(new StringBuilder()).append(text).append(read).append("\n").toString();
       System.out.println(text);//just to make sure it is reading
     }
            in.close();
            display.setText(text);
     
    }

    Only problem is, it is not reading the first line of text from the file?

  5. #4
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    Default Re: Reading a file with bufferedreader

    Sorry! Nevermind, I figured out why!! Sheesh, that was simple :[

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    Default Re: Reading a file with bufferedreader

    Quote Originally Posted by ppata View Post
    Sorry! Nevermind, I figured out why!! Sheesh, that was simple :[
    Usually the hardest questions have the simplest solutions.
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  7. The Following User Says Thank You to aussiemcgr For This Useful Post:

    ppata (November 20th, 2010)

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