Re: Displaying/Pulling Images using JDBC ...

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: "Ho, Khanh" <Khanh(dot)Ho(at)team(dot)telstra(dot)com>
Cc: The Hermit Hacker <scrappy(at)hub(dot)org>, pgsql-jdbc(at)postgresql(dot)org
Subject: Re: Displaying/Pulling Images using JDBC ...
Date: 2001-05-14 01:12:42
Message-ID: 200105140112.f4E1CgB02376@candle.pha.pa.us
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I am attaching a JDBC patch that is about to be applied for 7.2.
Perhaps this fixes the problem because it deals with BLOBS.

> Hi Marc,
>
> I seem to be having the same problem as you when trying to insert
> audio files into the database. They are inserted OK using
> PreparedStatement.setBinaryStream(), but the data is truncated
> when retrieved using PreparedStatement.getBinaryStream().
> This occurs using the jdbc7.1beta5 driver.
>
> Interestingly, when I try to use an older JDBC driver (jdbc7.1beta4), it
> manages to correctly read back the object stored by the jdbc7.1beta5 driver.
> However, the jdbc7.1beta4 driver itself can't write the large object to the
> database. It keeps throwing an exception: InputStream as parameter not
> supported.
>
> Can you let me know if you find out the cause of the problem, or
> better still a solution?
>
> Thanks,
> Khanh Ho.
>
>
> > -----Original Message-----
> > From: The Hermit Hacker [mailto:scrappy(at)hub(dot)org]
> > Sent: Sunday, 13 May 2001 2:45 AM
> > To: pgsql-jdbc(at)postgresql(dot)org
> > Cc: peter(at)retep(dot)org(dot)uk
> > Subject: [JDBC] Displaying/Pulling Images using JDBC ...
> >
> >
> >
> >
> > Morning folks ...
> >
> > Been wracking our brains on this one for too long now ... have a
> > client that is trying to use JDBC to pull images stored in
> > the database,
> > and, from what we can gather, the images are coming out
> > 'truncated' ...
> >
> > If the client stores the images as ASCII (uuencoded) and pulls
> > those out, all works well, but if he stores them as
> > binary/raw images, the
> > images don't come out ...
> >
> > If he retrieves that image using psql and stores it to a file,
> > that file is fine, so apparently the backend is storing it
> > properly ...
> >
> > According to the table schema that we have, the image is being
> > stored as an 'oid' type ...
> >
> > In relation to the image settings, they are counting the bytes
> > that the stream is going to send to the client and verifying it on the
> > clients side, the numbers are not matching unless it is an ascii based
> > file....
> >
> > Both the backend server and the JDBC drivers are v7.1 ...
> >
> > Now, my thought on this is that it *sounds* like the JDBC is
> > hitting some sort of control character is the stream that
> > tells it to stop
> > sending the image ... is this possible? Some binary
> > character that needs
> > to somehow be trapped?
> >
> > Image content is a mostly a faxed document saved as .tif format.
> > But it could be anything and we derive it from the file name.
> > We upload
> > the document to the database. Please See the source
> >
> > Sample of the source they are using is as follows, is
> > there something
> > that we are seeing:
> >
> > PreparedStatement prepStmt = con.prepareStatement(selectstatement);
> > prepStmt.setString(1, medicalRecordId);
> > ResultSet rs = prepStmt.executeQuery();
> > if (rs.next()) {
> > medicalRecordId = rs.getString(1);
> > typeSOAP = rs.getString(2);
> > code = rs.getString(3);
> > String datetimetemp = rs.getString(4);
> > datetime = Timestamp.valueOf(datetimetemp);
> > testObject = rs.getString(5);
> > testResult = rs.getString(6);
> > note = rs.getString(7);
> > appointmentId = rs.getString(8);
> > patientId = rs.getString(9);
> > test = rs.getString(10);
> > category = rs.getString(11);
> >
> > //if(imageName == null){
> > if(imageNametemp != null){
> > imageName = rs.getString(12);
> >
> >
> > BufferedInputStream bis = new
> > BufferedInputStream(rs.getBinaryStream(13));
> > System.out.println("value of bis"+bis.toString());
> > //InputStream is = rs.getBinaryStream(13);
> >
> > //System.out.println("vale of inputstream"+is.toString());
> >
> > int TotLen=0;
> >
> > ByteArrayOutputStream imageOutputStream = new
> > ByteArrayOutputStream(8164);
> >
> > byte[] b = new byte[8164];
> > int len=0;
> >
> > try {
> > while( (len = bis.read(b,0,8164)) != -1 ) {
> > imageOutputStream.write(b,0,len);
> >
> > TotLen += len;
> > }
> > bis.close();
> > imageAsBytes = imageOutputStream.toByteArray();
> >
> > System.out.println("value of baoslenght"+imageAsBytes.length);
> > System.out.println("value of totlenght"+TotLen);
> >
> > System.out.println("vale of
> > baos"+imageOutputStream.toString());
> > }
> > catch(IOException e) {
> > }
> > }
> > prepStmt.close();
> >
> >
> > Marc G. Fournier ICQ#7615664
> > IRC Nick: Scrappy
> > Systems Administrator @ hub.org
> > primary: scrappy(at)hub(dot)org secondary:
> > scrappy(at){freebsd|postgresql}.org
> >
> >
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>
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--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
+ If your life is a hard drive, | 830 Blythe Avenue
+ Christ can be your backup. | Drexel Hill, Pennsylvania 19026

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