Java reading from file problem

Question

I have a file, let's call it text.txt. It contains a few lines of text. I am trying to read this in with my code so that I can edit it using my code, unfortunately whenever I try and read it, it simply returns null, and does not load the code at all. No error message or anything.

An example is a file with the following in it :

a
b
c
d
e
f

when loaded, it loads the following :

a
b
c
d
null

Which makes no sense to me whatsoever, since, if it is entering the while loop, it shouldn't be exiting! Can anyone help me out please ?

try
{
     File theFile = new File(docName);

     if (theFile.exists() && theFile.canRead())
     {  
        BufferedReader docFile;
        docFile = new BufferedReader(
              new FileReader(f));

        String aLine = docFile.readLine();

        while (aLine != null)
        {  
           aLine = docFile.readLine();
           doc.add( aLine );
        }

        docFile.close();
     }

Jong Bor Lee · Accepted Answer · 2011-02-26 20:06:42Z

3

Note that you are reading the first line with

String aLine = docFile.readLine();

and then you discard this line by doing

aLine = docFile.readLine();

inside the loop.

answered Feb 26, 2011 at 20:06

Jong Bor Lee

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1 Comment

johusman Over a year ago

Not to mention that he adds aLine to doc before checking if it's null.

Hovercraft Full Of Eels · Accepted Answer · 2011-02-26 20:08:38Z

0

Add the line before reading the next line. If you think about this logically, it should make sense, and if not, please ask.

answered Feb 26, 2011 at 20:08

Hovercraft Full Of Eels

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Comments

MikeH · Accepted Answer · 2011-02-26 20:20:10Z

0

In the while loop, if you flip the two statements, then it will add the line you know is not null, then check the next line. The way you have it now, the loop checks the line, then advances a line and adds the new one to doc, so it can be null, then exit after adding null.

answered Feb 26, 2011 at 20:20

MikeH

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Comments

Dead Programmer · Accepted Answer · 2011-02-26 20:29:42Z

0

while ( (aLine = docFile.readLine())!= null)
{  
     doc.add( aLine );
}

edited Feb 26, 2011 at 20:29

answered Feb 26, 2011 at 20:10

Dead Programmer

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