Snippet to create a file from the contents of a blob in Java

Question

I have some files stored in a database blob column in Oracle 9.

I would like to have those files stored in the file system.

This should be pretty easy, but

Answer 1

There is another way of doing the same operation faster. Actually the answer above works fine but like IOUtils.copy(in,out) it takes a lot of time for big documents. The reason is you are trying to write your blob by 4KB iteration. Simplier solution :

Blob blob = rs.getBlob(column);
InputStream in = blob.getBinaryStream();
OutputStream out = new FileOutputStream(someFile);
byte[] buff = blob.getBytes(1,(int)blob.getLength());
out.write(buff);
out.close();

Your outputStream will write the blob in one shot.

Edit

Sorry didn't see the Edit section on the intial Post.

Answer 2

You'd want to get the blob as an inputstream and dump its contents to the outputstream. So 'misery' should be something like:

Blob blob = rs.getBlob(column);
InputStream in = blob.getBinaryStream();
OutputStream out = new FileOutputStream(someFile);
byte[] buff = new byte[4096];  // how much of the blob to read/write at a time
int len = 0;

while ((len = in.read(buff)) != -1) {
    out.write(buff, 0, len);
}

If you find yourself doing a lot of IO work like this, you might look into using Apache Commons IO to take care of the details. Then everything after setting up the streams would just be:

IOUtils.copy(in, out);