How to read multiple dat files.

Question

Hello Everyone!
I am working on a project that requires one file that creates a JFrame with a current file title, JTextFields that accesses two .dat files and a JButton.
The user clicks a JButton to cycle through the first sequential .dat file. When the end of the first file is reached the file is closed, the JFrame title is changed to the second file title as the user continues to click the JButton to continue on viewing the second file?s records, until the second reaches the end of file.
The project requires using Try-Catches to catch the EOF exceptions and IOExceptions and Thread or Runnable.
I have been able to get one file to read and display its records; however, researching back through my text on how to read/write to files I haven?t been able to determine how to get to the end of the file and proceed to the next file without triggering the EOFException. I have even tried multiple Try-Catches (one for each file within the actionPerformed method) and that ends up ignoring the first file records and only displays the second files records.
This is a school project and we have only covered just the bare basics of Java over the last two months. So, any hints that anyone can provide can only be of what type of procedure will be needed or what procedure won?t help to complete the task, without giving away the solution.
I have spent approximately 40 hours of study time on this project and believe that I have definitely run into a major snag.
The following is the code I have so far:
import java.io.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class StudentRead extends JFrame implements ActionListener
   private JLabel gradStudentList = new JLabel("GRADUATE Student List");
   private JLabel undergradStudentList = new JLabel("UNDERGRADUATE Student List"); 
   private Font bigFont = new Font("Helvetica", Font.ITALIC, 24);
   private JLabel userprompt = new JLabel("View the students");
   private JTextField idNumText = new JTextField(4); 
   private JTextField lastNameText = new JTextField(15);
   private JTextField firstNameText = new JTextField(15);
   private JButton viewRecordButton = new JButton("View Record");
   private JLabel idNumberLabel = new JLabel("ID Number"); 
   private JLabel lastNameLabel = new JLabel("Last name"); 
   private JLabel firstNameLabel = new JLabel("First name");
   private Container con = getContentPane();
   DataInputStream gradStudentInStream;
   DataInputStream undergradStudentInStream;
   public StudentRead()
      super("Read Student Records");
      try
         gradStudentInStream = new DataInputStream(new FileInputStream("GradStudents.dat"));
         undergradStudentInStream = new DataInputStream(new FileInputStream("UndergradStudents.dat"));
      catch(IOException e)
         System.err.println("File not opened");
         System.exit(1);
      setSize(325, 200);
      con.setLayout(new FlowLayout());
      gradStudentList.setFont(bigFont);
      con.add(gradStudentList);
      con.add(userprompt);
      con.add(idNumberLabel);
      con.add(idNumText);
      con.add(lastNameLabel);
      con.add(lastNameText);
      con.add(firstNameLabel);
      con.add(firstNameText);
      con.add(viewRecordButton);
      viewRecordButton.addActionListener(this);
      setVisible(true);
      setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
   public void actionPerformed(ActionEvent e1)
      String lastName, firstName;     
      int IdNum;
      try
         IdNum = gradStudentInStream.readInt();      
         lastName = gradStudentInStream.readUTF();
         firstName = gradStudentInStream.readUTF();
         idNumText.setText(String.valueOf(IdNum));
         lastNameText.setText(lastName);
         firstNameText.setText(firstName);
      catch(EOFException e2)
         closeFile();
         System.exit(0);
      catch(IOException e3)
         System.err.println("Error reading file");
         System.out.println("out");      
         System.exit(1);
   public void closeFile()
      try
         gradStudentInStream.close();
         System.exit(0);
      catch(IOException e)
         System.err.println("Error closing file");
         System.exit(1);
   public static void main(String[] args)
      StudentRead rsr = new StudentRead();
}

Answer 1

deepak_1your.com wrote:
hi,
If you want to read a file guarding yourself agianst exceptions....
check this article.... the code presented in this article might suit your needs...
[http://1your.com/fusion/infusions/articles/readarticle.php?article_id=17|http://1your.com/fusion/infusions/articles/readarticle.php?article_id=17]
And how does that help with a DataInputStream?