Files and Streams in java -- How to display successive records

Question

Hi,
I developed an application in which I enter name and id in a gui. Each time I enter, the records are added in the sequential file.
Then I have a button to open that file. It also opens.
Then I have a button to read the records(which has name and id) in sequential order. Each time I click next button records should be displayed in their respective text boxes. But, only the 1st record is displyed. Then I get IOException. Why am I not able to move to records after 1st record. How could I disply records till EOF is reached.
Plz see my code for open function and read next function
private void openFile()
input=new ObjectInputStream(new FileInputStream("c:/file.dat"));
openf.setEnabled(false);
readf.setEnabled(true);
private void readNext()
rcrd=(Record)input.readObject();
String val[]= {String.valueOf(rcrd.getId()),rcrd.getName(),rcrd.getAddr()};
gui.setFieldValues(val);
Why am I not able to move to records after 1st record. How could I disply records till EOF is reached.

Answer 1

package files;
import java.io.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import files.FileGui;
import files.Record;
import java.util.*;
import java.lang.*;
public class CreateFile extends JFrame
     private ObjectOutputStream output;
     private FileGui gui;
     private JButton enter, readf, openf;
     private Record rcrd;
     private ObjectInputStream input;
     boolean eof;
     LinkedList link = new LinkedList();
     ListIterator li=link.listIterator();
     public CreateFile()
          super( "Creating sequential file" );
          getContentPane().setLayout( new BorderLayout() );
          gui = new FileGui();
          enter = gui.getTask1();
          enter.setText("Enter");
          enter.setEnabled(true);
          enter.addActionListener(
                    new ActionListener()
                         public void actionPerformed( ActionEvent e )
                              addRecord1();
          addWindowListener(
                    new WindowAdapter()
                         public void windowClosing( WindowEvent e )
                              if(output != null)
                                   closeFile();
                              else
                                   System.exit(0);
          openf = gui.getTask2();
          openf.setText("Open");
          openf.addActionListener(
                    new ActionListener()
                         public void actionPerformed(ActionEvent e)
                              openFile();
readf = gui.getTask3();
          readf.setText("Read Next");
          readf.addActionListener(
                    new ActionListener()
                         public void actionPerformed(ActionEvent e)
                              readFile();
          getContentPane().add(gui, BorderLayout.CENTER);
          setSize(300,200);
          show();
     private void readFile()
                    try
                         rcrd=(Record)input.readObject();
                         String val[]={String.valueOf(rcrd.getId()),rcrd.getName(),rcrd.getAddr()};
                         gui.setFieldValues(val);
                    catch(EOFException eof)
                         System.out.print("EOFException");
                    catch(ClassNotFoundException cnfe)
                         System.out.print("ClassNotFoundException");
                    catch(IOException ioe)
                         System.out.print("IOException");
     private void openFile()
               JFileChooser fileChooser = new JFileChooser();
               fileChooser.setFileSelectionMode(JFileChooser.FILES_ONLY);
               int result = fileChooser.showOpenDialog(this);
               if(result==JFileChooser.CANCEL_OPTION)
                    return;
               File fileName = fileChooser.getSelectedFile();
               if(fileName==null || fileName.getName().equals(""))
                    JOptionPane.showMessageDialog(this, "Invalid file name", "Invalid file name", JOptionPane.ERROR_MESSAGE);
               else
                    try
                         //File fileName=new File("c:/file.txt");
                         input=new ObjectInputStream(new FileInputStream("c:/file.dat"));
                         openf.setEnabled(false);
                         readf.setEnabled(true);
               catch (Exception e)
                    System.out.println("Error in opening file");
     private void closeFile()
          try
               output.close();
               System.exit(0);
          catch(IOException ex)
               JOptionPane.showMessageDialog(this, "Error Closing File", "Error", JOptionPane.ERROR_MESSAGE);
               System.exit(1);
     private void addRecord1()
          String[] fieldValues = gui.getFieldValues();
          if(! fieldValues[0].equals(""))
               try
                    int id=Integer.parseInt(fieldValues[0]);
                    if(id>0)
                         Record rcrd = new Record(id, fieldValues[1], fieldValues[2]);
                         System.out.println(" " +rcrd.getString());
                         link.add(" " +rcrd.getString());
                         //System.out.println("Hello3");
                         FileOutputStream fos = new FileOutputStream("c:/file.dat",true);
                         output = new ObjectOutputStream(fos);
                         output.writeObject(rcrd);
                         output.flush();
                         //gui.clearFields();
                         readf.setEnabled(true);
               catch (NumberFormatException nfe)
                    JOptionPane.showMessageDialog(this, "Incorrect id", "Invalid number formate", JOptionPane.ERROR_MESSAGE);
               catch (IOException io)
                    closeFile();
     public static void main(String args[])
          new CreateFile();
}