Re: write read string data

From:

Patricia Shanahan <pats@acm.org>

Newsgroups:

comp.lang.java.help

Date:

Tue, 20 Nov 2007 18:47:02 -0800

Message-ID:

<fi0678$1kg5$1@ihnp4.ucsd.edu>

bH wrote:

On Nov 20, 8:19 pm, Lew <l...@lewscanon.com> wrote:

bH wrote:

I am attempting to write data into a file and read it
back again.
The error occurs with reading the data file back,
or so it would appear as the current output of that
data is merely a column of null.

....

      // attempting to recover the data
      try {
        BufferedReader obj_in =
        new BufferedReader(new FileReader
        ("C:\\myarray.data"));
        tmp_array.equals (obj_in);
        obj_in.close();
      }

Patricia Shanahan wrote:

I don't see where you actually read any data. You open the input as a
BufferedReader, test whether an array is equal to the BufferedReader
object (it isn't), ignore the result of the test, and close the input.
Having written the data using ObjectOutputStream and its writeObject
method, you should read it using ObjectInputStream and its readObject
method.

Conversely, if you want to read from a FileReader (or FileInputStream), then
write to a FileWriter (FileOutputStream).

Serialization (the storage of objects via ObjectXxxStreams) is a dicey subject
and requires great care.

Also, do NOT do all this work in the constructor. Use the constructor only to
construct the object. Do all real work in other methods, called from an
instance of the object that was created in main().

--
Lew- Hide quoted text -

- Show quoted text -

Hi All,

I am frustrated,

I have tried your suggesstions and see nothing that looks like the
original data.

Your recommendations have, in my opinion have been inconsistant.

Why?

The advice is inconsistent because there are several good solutions to
the problem. Also, we varied in how much extra advice we gave. For
example, I didn't point out the undesirability of doing so much work in
the constructor, but agree with that comment.

The most basic choice you need to make is between continuing to use
ObjectStreamWriter, writing out serialized data, or switching to
managing separating the strings yourself.

I suggest making any choice of which solution to attempt, and then post
the latest version of your code.

Patricia