topic Re: [resolved] Create file from a blob input (oracle db) in Talend Studio

[resolved] Create file from a blob input (oracle db)

Anonymous — Thu, 30 Apr 2015 16:02:03 GMT

Hi,
I would like to create a picture (.jpg) from the blob data of an oracle table.
I have an oracle input that connects to the table "Photo" and retrieve the column "data" of type Blob.
How can I create the picture with this Blob data ?
I tried with a tMap and tJava, but the tMap will convert the blob into an "Object", so I don't know how I can work with this...
Thanks in advance for the help
Thomas

Re: [resolved] Create file from a blob input (oracle db)

Anonymous — Thu, 30 Apr 2015 16:30:57 GMT

There is currently only one way to do this: use the custom component tLOBDownload
https://exchange.talend.com/#marketplaceproductoverview:gallery=marketplace%252F1&pi=marketplace%252F1%252Fproducts%252F559%252Fitems%252F838

Re: [resolved] Create file from a blob input (oracle db)

Anonymous — Thu, 30 Apr 2015 16:46:17 GMT

I've not tried this with jpgs but I have recently been working with MS Docs stored in a db. I simply used the tFileOutputRaw to do this. Just supply it your blob data as an object and it should work.

Re: [resolved] Create file from a blob input (oracle db)

Anonymous — Fri, 01 May 2015 00:35:01 GMT

I actually started to reply to this before jlolling wrote his response. Since reading his post, I have double checked my response and have found that it isn't quite as easy as I made out. But I have a solution which makes it pretty straight forward.
The job I put together looks like this...
I am receiving an image (as a Blob) and an ID from the db input. The code in the tJavaRow converts the blob to a byte array. The byte array is then sent to the tFileOutputRaw and that produces the file successfully. The Java used in the tJavaRow is below....
ByteArrayOutputStream baos = new ByteArrayOutputStream();
java.sql.Blob blob = (java.sql.Blob)input_row.IMAGE;
byte[] buf = new byte;
java.io.InputStream in = blob.getBinaryStream();
int n = 0;
while ((n=in.read(buf))>=0)
{
baos.write(buf, 0, n);
}
in.close();
byte[] bytes = baos.toByteArray();
output_row.IMAGE = bytes;
output_row.ID = input_row.ID;

Re: [resolved] Create file from a blob input (oracle db)

Anonymous — Mon, 04 May 2015 13:40:20 GMT

Thank you both for your answers. I will try both solutions.
Thomas

Re: [resolved] Create file from a blob input (oracle db)

Anonymous — Tue, 05 May 2015 08:17:07 GMT

Hi,
Your method works fine rhall, the only problem (which in my case is quite important) is this:
I have my javarow linked directly to the fileoutputraw, and I defined the name that the file will have in the javarow... How can I get the value of the variable from the javarow in the fileoutputraw ? (I already tried with context, but I will save iteratively many photos, so the name is changing dynamically)?
Thanks in advance for the help!
Thomas

Re: [resolved] Create file from a blob input (oracle db)

Anonymous — Tue, 05 May 2015 09:06:39 GMT

Hi Thomas,
You can use the globalMap hashmap. Calculate the filename in your javarow component and then save it to the globalMap variable like below....
globalMap.put("filename", "myFile.jpg")
.... then when you want to use it in the file component, retrieve the value like below....
((String)globalMap.get("filename"))
Regards
Richard

Re: [resolved] Create file from a blob input (oracle db)

Anonymous — Tue, 05 May 2015 09:20:12 GMT

Hi rhall,
Thank you very much for your time.
Actually, I already tried this solution, but even tough the system.out.println swears that the "filename" path is correct in the javarow, the tfileoutputraw gives me a nullpointerexception ...
With 3 iterations, here is a sample of my code:
output_row.PATH = context.dir_photos+input_row.CODE_LOGIQUE+".jpg"; //comes from a tmap
globalMap.put("filename", output_row.PATH);
System.out.println((String)globalMap.get("filename")); //works correctly
And the execution is the following:
connecting to socket on port 4057
connected
/Users/talias/Desktop/mssql/photos/ULR_40244.jpg
java.lang.NullPointerException
java.lang.NullPointerException
/Users/talias/Desktop/mssql/photos/ULR_40244.jpg
/Users/talias/Desktop/mssql/photos/ULR_40244.jpg
java.lang.NullPointerException
disconnected
I guess I missed something ?^^
Thomas

Re: [resolved] Create file from a blob input (oracle db)

Anonymous — Tue, 05 May 2015 09:52:30 GMT

Ah yes, I forgot about this. There is a hack to get round this irritating issue with dynamic file names. You need to use a tFlowToIterate followed by a tIterateToFlow. I have changed my job to look like below....

In the tJavaRow I have created an extra String output where I create and output my filename. The tFlowToIterate puts the byte[] content and filename string into the globalMap hashmap. Then the tIterateToFlow takes them one row at a time and creates a flow out of them. This is then sent to the tFileOutRaw and allows it to create a new file for each row.
The tIterateToFlow is configured as below....

The tFileOutputRaw is configured as below....

This should work 🙂

Re: [resolved] Create file from a blob input (oracle db)

Anonymous — Tue, 05 May 2015 10:17:50 GMT

-POST EDITED-
I thought I had an error, but it looks like I also had to cast my row.FILEPATH to string (not just the row.IMAGE).
It finally works, you helped me a lot, thank you very much !
Thomas

Re: [resolved] Create file from a blob input (oracle db)

Anonymous — Fri, 23 Oct 2015 14:57:14 GMT

Hi ,
I am trying to retrieve text file from oracle database , trying to do it as shown above .
But there is a problem with the schema in tjavarow "cannot cast from byte to blob".
please help!
TIA
Hachi

Re: [resolved] Create file from a blob input (oracle db)

Anonymous — Fri, 11 Dec 2015 10:03:26 GMT

Hi do you know if this Component is comptible with TOS DI 6.1?
I have an error message "Component not loaded"

Re: [resolved] Create file from a blob input (oracle db)

Anonymous — Fri, 11 Dec 2015 10:53:41 GMT

The best way to download BLOBs is using the custom component tLOBDownload from Talend Exchange:
https://exchange.talend.com/#marketplaceproductoverview:gallery=marketplace%252F1&pi=marketplace%252F1%252Fproducts%252F559%252Fitems%252F838
This component is exactly made for this use case.

Re: [resolved] Create file from a blob input (oracle db)

Anonymous — Sat, 12 May 2018 08:07:00 GMT

It Showing only the images names .The images are not downloading ..

I followed Your Steps to download images from database. Please guide me how do this Talend job or Could You share your job.

Thank you..

Image_Extract.PNG

Re: [resolved] Create file from a blob input (oracle db)

Lr_Sudha — Fri, 30 Aug 2019 13:50:29 GMT

Hi ,

I have used tBLOBDownload component to get BLOB (PDF File) from oracle database. It's downloaded the file but unable to open, getting below error;

Adobe Reader could not open … because it is either not a supported file type or because the file has been damaged (for example, it was sent as an email attachment and wasn’t correctly decoded).

Any help is appreciated.

Thanks,

LRS

Re: [resolved] Create file from a blob input (oracle db)

trivikram — Mon, 08 Mar 2021 23:54:37 GMT

hi sudheers,

were you able to find the solution for this problem, i have the same issue, can you send me screenshot or solution for it.

Thank you.