Blobs and length +- 1
От | Philip Crotwell |
---|---|
Тема | Blobs and length +- 1 |
Дата | |
Msg-id | Pine.GSO.4.10.10103010908480.9611-100000@tigger.seis.sc.edu обсуждение исходный текст |
Ответ на | JBuilder4 (Catalin CIOCOIU <catalin.ciocoiu@inpg.fr>) |
Список | pgsql-jdbc |
Hi I am using Blobs with jdbc and postgres7.0.3 and noticed that my blobs were coming out of the database 1 byte shorter than they went in! The problem was that I was using byte[] b = blob.getBytes(1, (int)blob.length()); instead of byte[] b = blob.getBytes(0, (int)blob.length()); But the javadocs for java.sql.Blob says, that the position is 1 based: Returns as an array of bytes part or all of the BLOB value that this Blob object designates. The byte array contains up to length consecutive bytes starting at position pos. Parameters: pos - the ordinal position of the first byte in the BLOB value to be extracted; the first byte is at position 1 length - is the number of consecutive bytes to be copied It seems to me that this says that getBytes(1, length) should be the entire blob instead of all but the first byte. Is this a postgres jdbc bug, or am I misreading the javadocs? The fix would be to subtract one, ie: public byte[] getBytes(long pos,int length) throws SQLException { lo.seek((int)pos-1,LargeObject.SEEK_SET); return lo.read(length); } thanks, PHilip PS For what it is worth and if it is the case, I think it is a pretty dumb thing for sun to make blob byte arrays 1 based. I would actually prefer 0 based, but being compatible is probably more important.
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