What's up with a random number like this being displayed 889193265?

[Matthew Buska]

Hi to anyone who reads this I am trying to build 2 programs. The 1st program, called MailOrderWrite, is suppose to allow you to enter data and save it to a file called info.txt which seems to work fine as far as to my knowledge about Java programming. The 2nd program, called MailOrderRead, is suppose to grab the information from the txt file and display it appropriately in the two boxes. That is where I seem to be having my problem. Its displaying an odd result in only 1 of the boxes like 889193265. If anyone can help me I would appreciate it.

import java.io.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.text.*;
import java.util.*;
 
public class MailOrderWrite extends JFrame implements ActionListener
{
  //Declare output stream
  DataOutputStream ostream;
  
  //Construct a panel for each row
  JPanel firstRow = new JPanel();
  JPanel secondRow = new JPanel();
  JPanel thirdRow = new JPanel();
  
  //Construct a panel for the fields and buttons
  JPanel fieldPanel = new JPanel();
  JPanel buttonPanel = new JPanel();
  
  //Construct labels and text boxes
  JLabel msg = new JLabel("Please enter an item number and quantity.");
  JLabel itemNumLabel = new JLabel("Item Number:");
    JTextField itemNum = new JTextField(5);
  JLabel quanLabel = new JLabel("Quantity:");
    JTextField quan = new JTextField(3);
    
  //Construct button
  JButton submitButton = new JButton("Submit");
  
  public static void main(String[] args)
  {
    //set the look and feel of the interface
    try
    {
      UIManager.setLookAndFeel("com.sun.java.swing.plaf.motif.MotifLookAndFeel");
    }
    
    catch(Exception e)
    {
      JOptionPane.showMessageDialog(null, 
          "The UIManager could not set the Look and Feel for this application.", 
          "Error", JOptionPane.INFORMATION_MESSAGE);
    }
    
    MailOrderWrite f = new MailOrderWrite();
    f.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
    f.setSize(500, 300);
    f.setTitle("Mail Order Write");
    f.setResizable(false);
    f.setLocation(200, 200);
    f.setVisible(true);
  }
  
  public MailOrderWrite()
  {
    //Information for the drop-down menu
    
    Container c = getContentPane();
    c.setLayout((new BorderLayout()));
    fieldPanel.setLayout(new GridLayout(3, 1));
    FlowLayout rowSetup = new FlowLayout(FlowLayout.LEFT, 2, 2);
      firstRow.setLayout(rowSetup);
      secondRow.setLayout(rowSetup);
      thirdRow.setLayout(rowSetup);
    buttonPanel.setLayout(new FlowLayout(FlowLayout.CENTER));
    
    firstRow.add(msg);
    
    secondRow.add(itemNumLabel);
    secondRow.add(itemNum);
    
    thirdRow.add(quanLabel);
    thirdRow.add(quan);
    
    //Add rows to panel
    fieldPanel.add(firstRow);
    fieldPanel.add(secondRow);
    fieldPanel.add(thirdRow);
    
    //Add button to panel
    buttonPanel.add(submitButton);
  
    //Add panels to frame
    c.add(fieldPanel, BorderLayout.CENTER);
    c.add(buttonPanel, BorderLayout.SOUTH);
  
    //Add functionality to buttons
    submitButton.addActionListener(this);
    
    String filename = "info.txt";
    
    try
    {
      ostream = new DataOutputStream(new FileOutputStream(filename));
    }
    
    catch(IOException io)
    {
      JOptionPane.showMessageDialog(null, 
          "The program could not create a storage location.  Please check the " +
          "disk drive and then run the program again.", "Error", 
          JOptionPane.INFORMATION_MESSAGE);
      System.exit(1);
    }
 
    addWindowListener(
      new WindowAdapter()
      {
        public void windowClosing(WindowEvent e)
        {
          int answer = JOptionPane.showConfirmDialog(null, 
              "Are you sure you want to exit?", "Exiting the program", 
              JOptionPane.YES_NO_OPTION);
          if(answer == JOptionPane.YES_OPTION)
            System.exit(0);
        }
      }
    );
  }
  
  public void actionPerformed(ActionEvent e)
  {
    String arg = e.getActionCommand();
    
    if(checkFields())
    {
      try
      {
        ostream.writeUTF(itemNum.getText());
        ostream.writeUTF(quan.getText());
        
        JOptionPane.showMessageDialog(null,"The information has been saved.", 
            "Submission Succesful", JOptionPane.INFORMATION_MESSAGE);
      }
      
      catch(IOException c)
      {
        System.exit(1);
      }
      
      clearFields();
    }
  }
  
  public boolean checkFields()
  {
    if((itemNum.getText().compareToIgnoreCase("") < 1) || 
       (quan.getText().compareToIgnoreCase("") < 1))
    {
      JOptionPane.showMessageDialog(null, "You must complete all fields.", 
      "Data Entry Error", JOptionPane.WARNING_MESSAGE);
      return false;
    }
    
    else
    {
      return true;
    }
  }
  
  public void clearFields()
  {
    //Clear fields and reset the focus
    itemNum.setText("");
    quan.setText("");
    itemNum.requestFocus();
  }
}

import java.io.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
 
public class MailOrderRead extends JFrame implements ActionListener
{
  //Construct labels and text boxes
  JLabel itemNumLabel = new JLabel("Item Number:");
    JTextField itemNum = new JTextField(5);
  JLabel quanLabel = new JLabel("Quantity:");
    JTextField quan = new JTextField(3);
  JButton viewEventButton = new JButton("View File");
      
  Container con = getContentPane();
    
  DataInputStream istream;
    
  public MailOrderRead()
  {
    super("Mail Order");
    
    try
    {
      istream = new DataInputStream(new FileInputStream("info.txt"));
    }
      
    catch(IOException e)
    {
      System.err.println("Please open the file");
      System.exit(1);
    }
      
    con.setLayout(new FlowLayout());
    
    con.add(itemNumLabel);
    con.add(itemNum);
    con.add(quanLabel);
    con.add(quan);
    con.add(viewEventButton);
      
    viewEventButton.addActionListener(this);
    setSize(500, 300);
    setVisible(true);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  }
    
  public void actionPerformed(ActionEvent e1)
  {
    int theitemNum, thequan;//, itemNumber, quantityNumber;
    
    try
    {
      theitemNum = istream.readInt();
      thequan = istream.readInt();
      
      itemNum.setText(String.valueOf(theitemNum));
      itemNum.setText(String.valueOf(thequan));
    }
      
    catch(EOFException e2)
    {
      closeFile();
    }
      
    catch(IOException e3)
    {
      System.err.println("Can't read the stupid file");
      System.exit(1);
    }
  }
    
  public void closeFile()
  {
    try
    {
      istream.close();
      System.exit(0);
    }
    
    catch(IOException e)
    {
      System.err.println("Error closing the stupid file");
      System.exit(1);
    }
  }
    
  public static void main(String[] args)
  {
    MailOrderRead ref = new MailOrderRead();
    
      //set the look and feel of the interface
    try
    {
      UIManager.setLookAndFeel("com.sun.java.swing.plaf.motif.MotifLookAndFeel");
    }
    
    catch(Exception e)
    {
      JOptionPane.showMessageDialog(null, 
          "The UIManager could not set the Look and Feel for this application.", 
          "Error", JOptionPane.INFORMATION_MESSAGE);
    }
  }
}

[ August 18, 2004: Message edited by: Matthew Buska ]

[ edited to break long lines and to remove the evil tab character -ds ]
[ August 20, 2004: Message edited by: Dirk Schreckmann ]

[Joe Ess]

Being consistent would help. You write one thing:

 
ostream.writeUTF(itemNum.getText());
ostream.writeUTF(quan.getText());

then read something else:

 
theitemNum = istream.readInt();
thequan = istream.readInt();

[Matthew Buska]

Can you explain more to a Java programming newbie please?

[Joe Ess]

You write a String to file. Lets say "123". It gets stored as a bunch of bytes (file contents in hex): 0003313233
You then try to read an int out of that file. Java doesn't care that you originally wrote a String. It's going to do what you tell it to do. Int's in Java are 32 bits, so we grab the first 32 bits out of the file: 00033132 hex or 209202 decimal. There you have it. A big weird number. But not random. It's what you asked for.
So use the same read/write methods. Either read/writeUTF or read/writeInt. And get familiar with the
Java Tutorial. In this case, the Chapter on DataInputStream would be particularly useful.

[Ilja Preuss]

I guess readInt doesn't do what you think it does.

It does *not* read a String and parses it to an int.

It *does* instead read a fixed number of bytes and interpretes their bits as an int. That is, it can only read something that was written by writeInt beforehand.

Does that help?