displaying byte array as image in IE

[P. Ingle]

Hi,

I have following method in a servlet. It calls ImgTable.getImage() method which gets Blob data from database, converts it into bytes (using getBytes) and return byte array.
Once I have the byte array in servlet, I just want to display the image.
It is not displaying anything - just shows empty image box with big red X on top left corner.

Please take a look and let me know if I am missing anything.

-------------------------------------------------------------------
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

System.out.println("in doGet method");
try {
ImgTable img = new ImgTable();
// get image data in form of byte array
byte[] buff = img.getImage();
// buff now image data in forma of byte array
if (buff == null) {
System.out.println("failed");
} else {
System.out.println("got byte array of size: " + buff.length);
//display it on browser
response.setContentType("image/jpeg");
ServletOutputStream ostr = response.getOutputStream();
response.setContentLength(buff.length);
ostr.write(buff);
ostr.flush();
ostr.close();
}
} catch (Exception x) {
x.printStackTrace();
}
} // end doGet

[Bear Bibeault]

I assume this servlet is being referenced by an <img> tag on the page?

[Bear Bibeault]

Btw, please use the UBB CODE tags when posting code.

[Ben Souther]

I did it by writing one byte at a time to the ServletOuputStream (from a file not from a db).

            in = new BufferedInputStream(
                getServletContext().
                    getResourceAsStream("WEB-INF" + filename));
                                                                                    
            response.setContentType(contentType);
            response.setHeader("Content-Disposition",
                               " inline; filename=" + filename);
                                                                                    
            ServletOutputStream out = response.getOutputStream();
                                                                                    
            byte[] buffer = new byte[4 * 1024];
                                                                                    
            int data;
            while((data = in.read(buffer)) != -1){
                out.write(buffer, 0, data);
            }
            out.flush();
 

 

  

[P. Ingle]

Originally posted by Bear Bibeault:
I assume this servlet is being referenced by an <img> tag on the page?

Yes - as

<IMG src="servlet/packageName.servletName"></img>

[tripti pandey]

Hey..were you able to find solution for this problem, i am facing same problem. I have a image as byte array that i need to display, following is the code i wrote in custom tag for the same :

OutputStream o = response.getOutputStream();
o.write(byteImage);
o.flush();
o.close();

In the JSP i am using following code
<img src="displayImage.jsp">

and this displayImage.jsp finally calls the custom tag. However, it seems that img tag is not accepting jsp. My debugger never reaches inside the custom tag implementation.

Please help

[Bear Bibeault]

<img src="displayImage.jsp">

You are beating yourself in the head with a hammer trying to render binary data from a JSP. You are much better off doing this sort of thing in a servlet.

More info on why JSP is such a poor technology choice can be had in this article.

[tripti pandey]

my query basically is can an img tag point to jsp, will jsp be called in that case?
please reply polietly, else dont

[David O'Meara]

There may be a language issue here, but Bear's reply was not meant to be offensive.

[Bear Bibeault]

"tp",

There aren't many rules that you need to worry about here on the Ranch, but one that we take very seriously regards the use of proper names. Please take a look at the JavaRanch Naming Policy and adjust your display name to match it.

In particular, your display name must be a first and a last name separated by a space character, and must not be obviously fictitious.

Thanks!
bear
JavaRanch Sheriff

[David O'Meara]

Originally posted by Tripti Pandey:
my query basically is can an img tag point to jsp, will jsp be called in that case?

yes and yes.

[Bear Bibeault]

What part of my response did you find impolite?

[tripti pandey]

thanks

[David O'Meara]

"tripti",
please re-read Bears request to change your display name.

Display names must contain a first and last name. I recommend you change it back to the original value, since accounts with invalid display names get deleted.

thanks,
Dave.

[dema rogatkin]

JSp should work fine, just get hand on out stream and write binary data. let me know if it isn't working. BTW Does anybody have a code for generation an image with text not recognizable by OCR, something similar to Google mail when you do many failed login attempts you start to getting an image.

[David O'Meara]

I believe it is referred to as 'Capcha' or 'Captcha' and there is a Java API available for it. Unfortunately I don't have any more information at this stage, but tell us how you go.