Re: write read string data

From:

bH <bherbst65@hotmail.com>

Newsgroups:

comp.lang.java.help

Date:

Thu, 22 Nov 2007 07:53:54 -0800 (PST)

Message-ID:

<130b736e-b22e-434a-bbae-41b7ffc1bd80@g21g2000hsh.googlegroups.com>

On Nov 21, 5:26 am, Roger Lindsj=F6 <news.nos...@tilialacus.net> wrote:

bH wrote:

On Nov 20, 11:09 pm, Roedy Green <see_webs...@mindprod.com.invalid>
wrote:

On Tue, 20 Nov 2007 07:02:20 -0800 (PST), bH <bherbs...@hotmail.com>
wrote, quoted or indirectly quoted someone who said :

I am attempting to write data into a file and read it
back again.

You have to read back with the same technique you write out with.

e.g. write objects / read objects.
write binary / read binary
write encoded chars / read encoded chars

Seehttp://mindprod.com/applet/fileio.html
for sample code to do it various ways.

You might do it each way and examine the file with a hex viewer to
understand the different formats.
--
Roedy Green Canadian Mind Products
The Java Glossaryhttp://mindprod.com

Hi All.

I am not sure, at this point, if this is what was expected.

bH

import java.io.*;

public class Example4withIO {

  public static void main(String[] args) {
    Example4withIO example4withIO =
      new Example4withIO();
    GetData getData1 = new GetData();
  }
  public Example4withIO() {
    System.out.println("inside Example4withIO");
    // final String[] names = {"First Name",
    // "Last Name", "Favorite Color",
    // "Favorite Number", "Vegetarian"};
    final Object[][] data = {
      {"Mark", "Andrews", "Red", new Integer(2),
        Boolean.TRUE},
      {"Tom", "Ball", "Blue", new Integer(99),
        Boolean.FALSE},
      {"Alan", "Chung", "Green", new Integer(838),
        Boolean.FALSE},
      {"Jeff", "Dinkins", "Turquois", new Integer(8),
        Boolean.TRUE},
      {"Amy", "Fowler", "Yellow", new Integer(3),
        Boolean.FALSE},
    };
    try {
      FileOutputStream fileOut =
        new FileOutputStream("C:\\myarray.data");
      ObjectOutputStream objOutStream =
        new ObjectOutputStream (fileOut);
      objOutStream.writeObject(data);
      objOutStream.flush();
      objOutStream.close();
    }
    catch (IOException e)
    {
      System.out.println("error getting data");
    }
  }
}

import javax.swing.*;
import java.io.*;

public class GetData extends JPanel {

  String tempStrng = new String();

  public GetData () {
    System.out.println("inside GetData");
    try {
      FileInputStream fileIn =
        new FileInputStream("C:\\myarray.data");
      ObjectInputStream objInStream =
        new ObjectInputStream(fileIn);
      tempStrng.equals(objInStream.readObject());
      if(tempStrng!= null){
        System.out.println(tempStrng); //no data
      }
      objInStream.close();
    }
    catch (Exception ee) {
      ee.printStackTrace();
    }
  }
}

I'm not sure what you are trying to do when reading the object back.
Originally you stored a Object[][], and then you compare it to a String.
The value of the comparison (true or false) is ignored and you happily
continue with checking if your string is not null. Perhaps you wanted
something like this:

import javax.swing.*;
import java.io.*;

public class GetData extends JPanel {

   Object[][] tempObj;

   public void GetData () {
     System.out.println("inside GetData");
     try {
       FileInputStream fileIn = new FileInputStream("C:\\myarray.data");=

       ObjectInputStream objInStream = new ObjectInputStream(fileIn);
       tempObj = (Object[][])(objInStream.readObject());
       if(tempObj!= null){
        for (Object[] oa: tempObj) {
           for (Object o: oa) {
             System.out.print(o);
             System.out.print(" ");
           }
           System.out.println();
         }
       }
       objInStream.close();
     }
     catch (Exception ee) {
       ee.printStackTrace();
     }
   }

}

Note, I have not compiled this.

//Roger Lindsj=F6- Hide quoted text -

- Show quoted text -

Hi Roger,

Thanks for your help. It looks great, compiles with no
errors, but produced no lines of output.

I revised your work, to something that I understood.
Your efforts were a clue what to write. It finally
read the file after compiling (code below).
I am now able to combine it to put it into
the original table (not incuded here).

This was my challenge: Take a program that displayed data
in a table, then break it apart,
1. Write that data to a file.
2. Get the data from the file.
3. Display it in the table that was originally used.

Simply "a game of reassembling all the puzzle parts that
were tossed into the box in a specific order now
displayed on the table top again for all to see".

Thanks to all for your patience and efforts,

bH

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

    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();
    }
  }
}