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Error in Dowlnoading

 
vinoth ar
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hi friends..

here i tried to write program to download a jpeg image from folder Resource folder. it is downloading a jpeg image as ordinary file with 0 bytes. with name of file as dload(servlet name). i couln`t trace the logical could you correct me..








thank you...
 
Bauke Scholtz
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You´re forgotten to set the response headers content-length and content-disposition.
 
vinoth ar
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hi Bauke Scholtz,

can you please explain me. why we need those functions. i`ve some knowledge about setcontentlen explght().. no knowledge about diposition.

can you explain for me.

thanks
 
Bauke Scholtz
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Uh. There is no why. The HTTP specification state so.
 
vinoth ar
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hi Bauke Scholtz ,
i can`t get you. anyways thanks for your. kind reply.
 
Bauke Scholtz
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It´s just, say, the law of HTTP.

http://www.w3.org/Protocols/rfc2616/rfc2616.html

Asking "why so?" makes no sense. It´s just because it is definied so.
 
Paul Clapham
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It also doesn't help that you read and discarded an unknown number of bytes from the JPG before your loop that tries to copy it to the response.
 
Hendy Setyo Mulyo
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vinoth ar wrote:hi friends..

here i tried to write program to download a jpeg image from folder Resource folder. it is downloading a jpeg image as ordinary file with 0 bytes. with name of file as dload(servlet name). i couln`t trace the logical could you correct me..


First, you should make sure that the image file you want to download is in the correct path.

InputStream is = context.getResourceAsStream("/Resource/vino.jpeg");

In other words, you should check whether is != null;

 
Bauke Scholtz
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I have not checked the code closely, but all of above is ultimately correct. Your code is not robust enough.
You may find this example useful then: http://balusc.blogspot.com/2007/04/imageservlet.html

Besides, using POST for this makes no sense. Rather use GET. The <img src> always use GET. And no, you shouldn't call doPost() inside doGet().
 
Paul Clapham
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In particular line #19 will read up to 46000 bytes of the resource into a byte array. You ignore this and just stream the rest of the resource out to the response.
 
Edwin Stephens
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Hello Vinoth,

You can also use the ImageIO class to read the jpeg image file and write it to the response output stream, like this:



This technique is detailed here:
http://www.avajava.com/tutorials/lessons/how-do-i-return-an-image-from-a-servlet-using-imageio.html

Hope that helps,
Edwin
 
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