Re: Zipping multiple BLOBs
On Feb 18, 5:14 pm, Ian Shef <inva...@avoiding.spam> wrote:
cdefelice <chris.defel...@gmail.com> wrote innews:4c1c43f8-432a-4439-8e69=
-ece8b9348012@z11g2000yqz.googlegroups.com:
Hello,
First of all, I have virtually no experience with Java but I've been
tasked with putting this thing together and I've finally hit a dead
end. Basically, what I am creating is a PL/SQL (Oracle 10g) web form
so that clients may download specific files stored as BLOBs from the
database. This is fine and dandy if they want to download one file at
a time. What I need to do is come up with a way to pull multiple BLOB
files, zip them up in one big BLOB, and serve it as a download. Since
this cannot be done in PL/SQL alone, I turned to Java.
So far I have not been able to find one successful example of how to
do this. What I have so far produces a zip file with only the first of
the selected BLOBs inside of it. I am basically just looping through
the list of selected BLOBs while passing each selected BLOB to the
Java procedure as well as the zip BLOB but it doesn't seem to be
appending anything to the zipped BLOB after the first iteration. Here
is the code:
I admit that I don't know SQL, don't know BLOBs, and haven't worked with
zip files from Java, but I am going to take a shot at this anyway.
public static void zipBlob(oracle.sql.BLOB srcBlob,
oracle.sql.BLOB
dstBlob[],java.lang.String name)
String should be sufficient, java.lang.String is overkill. java.lang.*=
is
automatically imported by the compiler without any action on your part. =
This is not an error, it just looks peculiar.
{
try
{
Connection conn =
DriverManager.getConnection("jdbc:default:connection:");
OutputStream outBuffer =
dstBlob[0].setBinaryStream(0);
I see dstBlob[0] but I don't see any loop to get any other BLOBs. I al=
so
don't see any protection against the possibility that there is no 0
element.
InputStream inBuffer = srcBlo=
b.getBinaryStream();
ZipOutputStream zip = new
ZipOutputStream(outBuffer);
zip.setMethod(ZipOutputStream.D=
EFLATED);
byte[] tmpBuffer = new byte[1=
024];
ZipEntry entry = new ZipEntry=
(name);
What are you going to use for the name of any additional entries, once yo=
u
put a loop in to handle more entries?
zip.putNextEntry(entry);
int n;
while ((n = inBuffer.read(tmp=
Buffer)) >= 0)
0, n);
}
zip.close();
}
catch (SQLException e)
{
System.err.println(e);
}
catch (IOException e)
{
System.err.println(e);
}
}
I appreciate any examples or pointers as to why this is not working.
Thanks
I hope this helps. Good luck!
First and foremost, thank you for replying. I really appreciate it.
In PL/SQL I am looping through the list of selected BLOB files and
calling the Java procedure, each time passing it a new BLOB source
file, the file name of that specific BLOB source, and the same BLOB
destination (zip) file. I'm just trying to pass the Java procedure one
new file at a time and append it to the zip file. I see what you mean
about looping through the destination BLOB array. My understanding,
and correct me if I'm wrong, is that each time the Java procedure is
called I should be able to determine the array count of the
destination BLOB and pick up at the end and append more zip entries. I
have tried to do exactly this with something like "int z_length =
dstBlob.length();" or "int z_length = getLength(dstBlob);". My problem
is that I don't know 1) which one returns the array count vs the BLOB
size 2) how to use the z_length value once I've obtained it. If I try
"dstBlob[z_length].setBinaryStream(0);" I get a
java.lang.ArrayIndexOutOfBoundsException exception.