Need some help extracting images from blobs...

Question

hi,
I want to upload a image to a oracle blob and then download it and display it into a browser using jsp. I am new to java as will as oracle and doing a project for the first time. I have searched the internet and found out some links:
http://fdegrelle.over-blog.com/article-992927-6.html
http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:232814159006
http://forums.devx.com/archive/index.php/t-142347.html
I feel the solutions given are very vogue and also tried the solutions posted in java forums itself. I would like to have simple example, step by step explanation for uploading an image into a oracle blob,download the image and display it in a browser using a jsp so that i can understand the concepts.
Thank you SUN and JAVA PROGRAMMERS.

Answer 1

thanks yogee,
The creators of these examples have assumed that the developers are advanced users. I am not an advanced user. I am not even a intermediate user.
1.....................................I understood this(Create Table)
create table demo
( id        int primary key,
  theBlob    blob
)/2...................................I understood this too(I suppose we are mapping the folder path)
create or replace directory my_files as '/export/home/tkyte/public_html';3..................................I understood this too(upload the file into the blob)
declare
    l_blob    blob;
    l_bfile    bfile;
begin
    insert into demo values ( 1, empty_blob() )
    returning theBlob into l_blob;
    l_bfile := bfilename( 'MY_FILES', 'aria.gif' );
    dbms_lob.fileopen( l_bfile );
    dbms_lob.loadfromfile( l_blob, l_bfile,
                               dbms_lob.getlength( l_bfile ) );
    dbms_lob.fileclose( l_bfile );
end;
/4..................................we are creating a package here. I got it.
create or replace package image_get
as
    procedure gif( p_id in demo.id%type );
end;
/5...................................we are suppose to use this to extract the file from the blob. But where does this get stored?
create or replace package body image_get
as
procedure gif( p_id in demo.id%type )
is
    l_lob    blob;
    l_amt    number default 30;
    l_off   number default 1;
    l_raw   raw(4096);
begin
    select theBlob into l_lob
        from demo
         where id = p_id;
        -- make sure to change this for your type!
    owa_util.mime_header( 'image/gif' );
        begin
           loop
              dbms_lob.read( l_lob, l_amt, l_off, l_raw );
              -- it is vital to use htp.PRN to avoid
              -- spurious line feeds getting added to your
              -- document
              htp.prn( utl_raw.cast_to_varchar2( l_raw ) );
              l_off := l_off+l_amt;
              l_amt := 4096;
           end loop;
        exception
           when no_data_found then
              NULL;
        end;
end;
end;
/6...............................Execute the procedure!
exec image_get
7..................................What after this step?
I do not know servlets. I only know JSP? If you can please write a simple servlet to access the data and display it on the browser
Sample servlet code is in the link as a last user comment. I couldn't understand head or tail.
http://forums.devx.com/archive/index.php/t-142347.html
I appreciate your help.
Message was edited by:
ted_anderson