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  1. #1
    Renxx is offline Member
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    Default Writing data to file, but not overwriting it.

    This is my DataBase class, which has a GUI. On GUI there is a "Add" button and text field. After i have filled text field with name and clicked "Add", it overwrites Users.txt file with text field input. My question is, how can I make so that after I have clicked "Add", it doesn't overwrite existing file, but it adds another name on second line, if there happens to be a name on first line already.

    Java Code:
    class DataBase {
       
       private BufferedWriter fileStream;
       
     //  private Formatter x;
       
       public void openFile() {
          try {
             fileStream = new BufferedWriter( new FileWriter("Users.txt"));
          } catch (IOException e) {
               e.printStackTrace();
          }
               // x = new Formatter("users.txt");
       }
       
       public void addUser(String firstName,String lastName) {
      //    x.format("%s\t%s\n",firstName,lastName );
          try {
             fileStream.write(String.format("%s\t%s\n", firstName,lastName));
          } catch (IOException e) {
             e.printStackTrace();
          }
       }
       
       public void closeFile() {
        //  x.close();
          try {
             fileStream.close();
          } catch (IOException e) {
             e.printStackTrace();
          }
       }
    }

  2. #2
    JosAH's Avatar
    JosAH is offline Moderator
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    Default Re: Writing data to file, but not overwriting it.

    Read the API documentation for the FileWriter class; it has another constructor that makes the writer write passed the end of the original file, i.e. it appends new content.

    kind regards,

    Jos
    The only person who got everything done by Friday was Robinson Crusoe.

  3. #3
    Fubarable's Avatar
    Fubarable is offline Moderator
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    Default Re: Writing data to file, but not overwriting it.

    FileWriter has a second constructor, one that takes a boolean that if called will solve your problem. Please have a look at the FileWriter API for more on this: FileWriter API

    edit: gak! scooped by a Grolsch-swilling Dutchman!

  4. #4
    JosAH's Avatar
    JosAH is offline Moderator
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    Default Re: Writing data to file, but not overwriting it.

    Quote Originally Posted by Fubarable View Post
    edit: gak! scooped by a Grolsch-swilling Dutchman!
    <diabolical laughter>giggle, giggle</diabolical laughter>, man I'm feeling so speedy tonight, I almost answer questions before they were asked! I go voooooom!

    kindest regards,

    Jos ;-)
    The only person who got everything done by Friday was Robinson Crusoe.

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