Programming Forums > Application Development > Java

chrome_knob · May 19th, 2005, 2:30 PM

Here's the basic structure of my program

import stuff;
-----------------------------------------------
public class MapImage extends JFrame {

 public MapImage()
 {
  super( "Mapped Image" );

  setSize( 400, 165 );
  show();
 }
-----------------------------------------------
 public void paint( Graphics g )
 {

 }
-----------------------------------------------
 public static void main( String args[] )
 {
  MapImage app = new MapImage();

  app.addWindowListener(
   new WindowAdapter() {
    public void windowClosing( WindowEvent e )
    {
     System.exit( 0 );
    }
   }
  );
 }
}

The second method, public void paint, is the problem. I've left it blank because it's fairly long but I'll bring up the important parts here. First I open a file for input.

(Toggle Plain Text)

  File inputFile = new File( "map.gz" );
  FileInputStream in = new FileInputStream( inputFile );

Then I read the first three byte values of the file and use them to set the color.

g.setColor( new Color( c[0], c[1], c[2] ) );

I have a pixel drawn on the screen.

g.drawLine( x,y,x,y );

Then I read the next three bytes of the file to get the next color and print the next pixel untill the entire file has been read. I'm left with a graphical representation of the file where each pixel represents three bytes. Then

in.close();

But when I try to compile it I get these:

unreported exception java.io.FileNotFoundException
unreported exception java.io.IOException

Where do I need to type in the "throws IOException" statement in order to fix this? I've tried it at the end of all three methods but still get the same problem.

ZenMasterJG · May 19th, 2005, 4:23 PM

put the code where your opening the file into a try statement, like this.

(Toggle Plain Text)

try {
  File inputFile = new File( "map.gz" );
  FileInputStream in = new FileInputStream( inputFile );
} catch(Exception e) {
  System.out.println(e);
  System.exit(1);
}

chrome_knob · May 19th, 2005, 5:45 PM

Thanks. It worked.

May 19th, 2005, 2:30 PM	#1
chrome_knob Newbie Join Date: Apr 2005 Posts: 3 Rep Power: 0	exception handling Here's the basic structure of my program (Toggle Plain Text) import stuff; ----------------------------------------------- public class MapImage extends JFrame { public MapImage() { super( "Mapped Image" ); setSize( 400, 165 ); show(); } ----------------------------------------------- public void paint( Graphics g ) { } ----------------------------------------------- public static void main( String args[] ) { MapImage app = new MapImage(); app.addWindowListener( new WindowAdapter() { public void windowClosing( WindowEvent e ) { System.exit( 0 ); } } ); } } import stuff; ----------------------------------------------- public class MapImage extends JFrame { public MapImage() { super( "Mapped Image" ); setSize( 400, 165 ); show(); } ----------------------------------------------- public void paint( Graphics g ) { } ----------------------------------------------- public static void main( String args[] ) { MapImage app = new MapImage(); app.addWindowListener( new WindowAdapter() { public void windowClosing( WindowEvent e ) { System.exit( 0 ); } } ); } } The second method, public void paint, is the problem. I've left it blank because it's fairly long but I'll bring up the important parts here. First I open a file for input. (Toggle Plain Text) File inputFile = new File( "map.gz" ); FileInputStream in = new FileInputStream( inputFile ); File inputFile = new File( "map.gz" ); FileInputStream in = new FileInputStream( inputFile ); Then I read the first three byte values of the file and use them to set the color. g.setColor( new Color( c[0], c[1], c[2] ) ); I have a pixel drawn on the screen. g.drawLine( x,y,x,y ); Then I read the next three bytes of the file to get the next color and print the next pixel untill the entire file has been read. I'm left with a graphical representation of the file where each pixel represents three bytes. Then in.close(); But when I try to compile it I get these: unreported exception java.io.FileNotFoundException unreported exception java.io.IOException Where do I need to type in the "throws IOException" statement in order to fix this? I've tried it at the end of all three methods but still get the same problem.

May 19th, 2005, 4:23 PM	#2
ZenMasterJG Hobbyist Programmer Join Date: Nov 2004 Location: Boston, MA Posts: 148 Rep Power: 4	put the code where your opening the file into a try statement, like this. (Toggle Plain Text) try { File inputFile = new File( "map.gz" ); FileInputStream in = new FileInputStream( inputFile ); } catch(Exception e) { System.out.println(e); System.exit(1); } try { File inputFile = new File( "map.gz" ); FileInputStream in = new FileInputStream( inputFile ); } catch(Exception e) { System.out.println(e); System.exit(1); }

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May 19th, 2005, 5:45 PM	#3
chrome_knob Newbie Join Date: Apr 2005 Posts: 3 Rep Power: 0	Thanks. It worked.

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Programming Forums > Application Development > Java

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