Store a file in a bytea

From: mmg <mathias(dot)degroof(at)gmail(dot)com>
To: pgsql-jdbc(at)postgresql(dot)org
Subject: Store a file in a bytea
Date: 2011-02-10 16:01:52
Message-ID: 1297353712985-3379578.post@n5.nabble.com
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Hi all,

I'm creating an application that will store files in a postresql database
and which will retrieve them later on. I store my data in a bytea column.
The problem I'm having is that when I retrieve the data later and write it
out, the resulting file is not the same as the original. When I open the
file it looks as though the ASCII codes were written out instead of the data
itself (so it looks as if the ASCII was encoded again as ASCII, causing me
to see ASCII codes when I open the file). I created a simple test program to
demonstrate this:

Connection conn =
DriverManager.getConnection("jdbc:postgresql://localhost/testdb", "test",
"test");
conn.createStatement().executeUpdate("DELETE FROM testtable");
PreparedStatement pstmt = conn.prepareStatement("INSERT INTO
testtable(data) VALUES(?)");
File file = new File("c:/t.txt");
FileInputStream fis = new FileInputStream(file);
pstmt.setBinaryStream(1, fis, (int) file.length());
pstmt.executeUpdate();
ResultSet rs = conn.createStatement().executeQuery("SELECT * FROM
testtable");
if (rs.next()) {
byte[] data = rs.getBytes("data");
FileOutputStream fos = new FileOutputStream("c:/t2.txt");
fos.write(data);
fos.close();
}
rs.close();
conn.close();

There is one table: testtable with a data colum which is a bytea. I read the
file c:/t.txt, store this as a stream then read it out again and write it to
c:/t2.txt. When I open t2.txt, I see the ASCII codes instead of the actual
text. I don't know what I'm doing wrong. I've tried reading it as a stream
from the database, but that doesn't work either. Any help is much
appreciated.
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