Re: please confirm something (jdbc)
stc, 29.11.2007 10:23:
// read
conn.setAutoCommit(true);
pstmt = conn.prepareStatement("select content from test where id = ? for
update";
pstmt.setString(1, "12345");
ResultSet rs = pstmt.executeQuery();
if (rs.next()) {
InputStream is = rs.getBinaryStream("content");
int n;
byte[] tmp = new byte[is.available()]; // available() returns 0!
FileOutputStream fos = new FileOutputStream("C:/Temp/12345.pdf");
while ((n = is.read(tmp)) != -1) {
fos.write(tmp, 0, n);
}
fos.close();
is.close();
}
rs.close();
pstmt.close();
conn.close();
The problem is that "available()" method returns 0 and "read()" method
blocks. What am I doing wrong?
available() cannot be used to retrieve the number of bytes for an
InputStream.
From the Javadocs:
"Returns the number of bytes that can be read (or skipped over) from
this input stream without blocking by the next caller of a method for
this input stream"
It does not claim to return the length of the underlying stream.
Actually I doubt that it even knows the size of the "source".
You should create your tmp buffer with a fixed size (e.g. new
byte[1024]), then it should work. I'm not sure I understand what you
mean with "read() blocks" but that could well be caused by your buffer
of length zero.
Thomas