Retrieves all or part of the BLOB value designated by this Blob object as a stream.
|pos||The ordinal position of the first byte in the BLOB value to be extracted.
The first byte is at position 1.
|length||The number of consecutive bytes to be copied.|
Returns a java.io.InputStream object that contains up to length consecutive bytes from the BLOB value designated by this Blob object, starting with the byte at position pos.