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getClass().getC lassLoader().ge tResource() problem....

52 New Member
Hi,
I'm very new to java... and I'm having a problem in getting a URL

Expand|Select|Wrap|Line Numbers
  1. URL url;
  2. url=getClass().getClassLoader().getResource(name);
  3. System.out.println(url);
This code works well when I supply a filename "abc.jpg" directly instead of name. But if I get the filename in "name" string.. then, the returned url value is null.

is there any difference in sending the argument to getResource() in these two different ways.

Thanks
Nov 4 '08 #1
8 33515
JosAH
11,448 Recognized Expert MVP
No, there is no difference; try it:

Expand|Select|Wrap|Line Numbers
  1. URL url;
  2. System.out.println("name: "+name); 
  3. url=getClass().getClassLoader().getResource(name);   
  4. System.out.println(url); 
  5. url=getClass().getClassLoader().getResource("abc.jpg");   
  6. System.out.println(url); 
  7.  
kind regards,

Jos
Nov 4 '08 #2
shreedhan
52 New Member
Thanks for your reply

I tried the above mentioned code and the output was

Expand|Select|Wrap|Line Numbers
  1. name: 
  2. abc.jpg
  3.  
  4. null
  5. file:/home/Shreedhan/workspace/test_4_sep/bin/abc.jpg
It shows "null" when "name" is there..
and it shows full path when "abc.jpg" is there..

I even tried concatenating the path to the name, but then it didn't work..


Thanks
Nov 5 '08 #3
r035198x
13,262 MVP
Show us the code where you have used this name variable.
Nov 5 '08 #4
JosAH
11,448 Recognized Expert MVP
Are you using "name" between double quotes? Don't do that, simply use: name.

kind regards,

Jos

ps. A simpler getClass().getR esource() als works properly.
Nov 5 '08 #5
shreedhan
52 New Member
The code I'm using is following..


Expand|Select|Wrap|Line Numbers
  1. public BufferedImage loadimage(String name){
  2.         URL url=null;
  3.         try{
  4.  
  5.  
  6.                System.out.println("name: "+name); 
  7.                url=getClass().getClassLoader().getResource(name);     
  8.                System.out.println(url); 
  9.                url=getClass().getClassLoader().getResource("shreedhan.gif");   
  10.                System.out.println(url); 
  11. return ImageIO.read(url);
  12.  
  13.  
  14.         }
  15.         catch (Exception e){
  16.             System.out.println("No such image file named "+name+" at "+url);
  17.             System.exit(0);
  18.             return null;
  19.         }
  20.     }
  21.  
Nov 5 '08 #6
shreedhan
52 New Member

ps. A simpler getClass().getR esource() als works properly.
I tried this one as well. But its giving the same result..

Thanks
Nov 5 '08 #7
JosAH
11,448 Recognized Expert MVP
I tried this one as well. But its giving the same result..

Thanks
If this works:

Expand|Select|Wrap|Line Numbers
  1. URL url= getClass().getResource("abc.jpg");
  2.  
... then this should work too:

Expand|Select|Wrap|Line Numbers
  1. String name= "abc.jpg";
  2. URL url= getClass().getResource(name);
  3.  
There is no more I can say about it.

kind regards,

Jos
Nov 5 '08 #8
shreedhan
52 New Member
Hi all,
I'm writing again here because I think I figured out the problem (not the solution). Sorry for not being completely descriptive previously.

I have two classes on same file . One of the methods in a class parses an XML file and returns String.
This string is used in another method of another class to load an image.

Now the code


Expand|Select|Wrap|Line Numbers
  1. class parse_Xml {
  2.     private Document doc;
  3.     public String player_image;
  4.  
  5.  
  6.     public parse_Xml(String file){
  7.         try{
  8.         DocumentBuilderFactory dbf=DocumentBuilderFactory.newInstance();
  9.         dbf.setValidating(false);
  10.         DocumentBuilder db=dbf.newDocumentBuilder();
  11.         doc=db.parse(new File(file));
  12.  
  13.         }catch(Exception e){
  14.             e.printStackTrace();
  15.         }
  16.     }
  17.     public String getImageName(){
  18.         NodeList child=doc.getDocumentElement().getChildNodes();
  19.         Node root=child.item(0);
  20.         Text name=(Text)root;
  21.         player_image=name.getNodeValue();
  22.         return player_image;                //it returns shreedhan.gif from test.xml
  23.     }
  24.  
  25.  
  26. }
  27.  
  28.  
  29.  
  30. public class sprite_test extends Canvas {
  31.     public static final int HEIGHT=600;
  32.     public static final int WIDTH=800;
  33.     public String imagename;
  34.     public int xpos=0;
  35.     public int ypos=HEIGHT/4;
  36.     public int dx=10;
  37.     public BufferStrategy buff;
  38.     public HashMap sprites;
  39.     public long usedTime;
  40.  
  41.     public sprite_test(){
  42.         .........
  43.     }
  44.  
  45.     public BufferedImage loadimage(){
  46.         URL url=null;
  47.         //System.out.println("in load image" + name);
  48.         try{
  49.             url=getClass().getResource(imagename);
  50.             return ImageIO.read(url);
  51.         }
  52.         catch (Exception e){
  53.             System.out.print("No such image file named "+imagename+" at "+url);
  54.             System.exit(0);
  55.             return null;
  56.         }
  57.     }
  58.  
  59. .....................
  60. ....................
  61.  
  62.  
  63.  
  64. public static void main(String args[])
  65.     {
  66.         sprite_test abc=new sprite_test();
  67.         parse_Xml imgObj= new parse_Xml("test.xml");
  68.         abc.imagename=imgObj.getImageName();
  69.  
  70.         abc.game();               //this method eventually calls loadimage
  71.     }
  72.  
  73. }
  74.  

gives an error like "No such image file named shreedhan.gif at null"

It is getting "shreedhan. gif" as imagename but it's not giving its url using getClass.getCla ssLoader().getR esource()



But when I replace parse_Xml class with a simple class like

Expand|Select|Wrap|Line Numbers
  1. public class parse_Xml{
  2.     public String getImageName(){
  3.         return "shreedhan.gif";
  4.     }
  5. }

it runs fine.. this way.

So, I'm not getting what's wrong here.

Thanks
Nov 15 '08 #9

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