Re: write read string data

From:
Lew <lew@lewscanon.com>
Newsgroups:
comp.lang.java.help
Date:
Thu, 22 Nov 2007 11:32:18 -0500
Message-ID:
<au6dnRvCxIaOMtjanZ2dnUVZ_judnZ2d@comcast.com>
bH wrote:

public class GetData extends JPanel {


It doesn't look like this class "is-a" JPanel. You use no JPanel
functionality; on the contrary, all your visible output is via System.out.

Also, the intent of class names is usually clearer with a noun (DataGetter)
than a verb, which latter is good for methods.

  Object[][] tempObj = new Object[5][5];
  public GetData () {


Don't do major work inside a constructor.

    System.out.println();
    System.out.println("inside GetData");
    System.out.println();

    try {
      FileInputStream fileIn =
          new FileInputStream("C:\\myarray.data");
      ObjectInputStream objInStream =
          new ObjectInputStream(fileIn);
      for (int ia = 0;ia<5;ia++){
        for (int ib = 0;ib<5;ib++) {
          tempObj[ia][ib] = objInStream.readObject();
          System.out.print(tempObj[ia][ib]);
          System.out.print(" ");
          System.out.println();
        }
      }
      objInStream.close();
    }
    catch (Exception ee) {
      ee.printStackTrace();
    }
  }
}


One point about safety. If the readObject() call blows up, you will never
close your Streams. You should put close() calls in a finally{} block, after
the Stream is instantiated, to ensure that they really do close.

public class DataGetter
{
  public void getData()
  {
   FileInputStream fileIn = new FileInputStream("myarray.data");
   if ( fileIn == null )
   {
     return;
   }
   ObjectInputStream objIn;
   try
   {
     objIn = new ObjectInputStream(fileIn);
   }
   catch( IOException ex )
   {
     objIn = null;
     logger.log( Level.SEVERE, "Open error on object input", ex );
   }
   if ( objIn == null )
   {
     try
     {
       fileIn.close();
     }
     catch( IOException ex )
     {
       logger.log( Level.SEVERE, "Close error on file", ex );
     }
     return;
   }

   try
   {
     for (int ia = 0; ia < 5; ia++)
     {
       for (int ib = 0; ib < 5; ib++)
       {
         temp [ia] [ib] = objIn.readObject();
         System.out.print( temp [ia] [ib] );
         System.out.print(" ");
         System.out.println();
       }
     }
   }
   catch( IOException exc )
   {
     logger.log( Level.SEVERE, "Processing error on object input", exc );
   }
   finally
   {
     try
     {
       objIn.close();
     }
     catch( IOException ex )
     {
       logger.log( Level.SEVERE, "Close error on object input", ex );
     }
     try
     {
       fileIn.close();
     }
     catch( IOException ex )
     {
       logger.log( Level.SEVERE, "Close error on file", ex );
     }
   }
  }
}

--
Lew

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