Re: JDBC + PostgreSQL + LargeObjects

Oh, i don't get an error message, instead, i see on the browser, the icon for a "not an image".
I tried to wget it, and the newly downloaded file does not match the size of the original image, and i cannot open it with an image viewer.
I used the same SQL sentence using the console (the terminal), and using lo_export, and the exported image is correctly exported.

On Mon, 18 Feb 2002 09:44:43 -0800
Barry Lind <barry(at)xythos(dot)com> wrote:

> Paulo,
>
> If you could mention what error you are getting and what version of the
> code you are using that would be helpful.
>
> --Barry
>
>
> Paulo Delgado wrote:
> > I'm writing a JSP which instead of generating HTML code, it sends an
> > image to the browser. The image is retrieved from the database, where it
> > is stored as a BLOB (an OID). I read the docs online, this is the URL:
> >
> > http://developer.postgresql.org/docs/postgres/jdbc-binary-data.html
> >
> > And this is the code (still not working)
> >
> >
> > <%@ page import="java.io.*" %>
> > <%@ page import="java.sql.*" %>
> > <%@ page import="org.postgresql.largeobject.*" %>
> >
> > <%
> > response.setContentType("image/jpeg");
> > out.close();
> > ServletOutputStream sos = response.getOutputStream();
> > try
> > {
> > Class.forName("org.postgresql.Driver");
> > }
> > catch(ClassNotFoundException cnfex)
> > {
> > cnfex.printStackTrace();
> > }
> > try
> > {
> > Connection mycon;
> > mycon=
> > DriverManager.getConnection("jdbc:postgresql://localhost:5432/database",
> > "userid" , "password");
> > mycon.setAutoCommit(false);
> >
> > // Get the Large Object Manager to perform operations with
> > LargeObjectManager lobj =
> > ((org.postgresql.Connection)mycon).getLargeObjectAPI();
> >
> > PreparedStatement ps = mycon.prepareStatement("SELECT pic FROM
> > mytable WHERE month='"+request.getParameter("m")+"' AND
> > year="+request.getParameter("y"));
> > ResultSet rs = ps.executeQuery();
> > if (rs != null) {
> > while(rs.next()) {
> > //open the large object for reading
> > int oid = rs.getInt(1);
> > LargeObject obj = lobj.open(oid , LargeObjectManager.READ);
> >
> > //read the data
> > byte buf[] = new byte[obj.size()];
> > obj.read(buf, 0, obj.size());
> >
> > //do something with the data read here
> > response.setContentLength(obj.size());
> > int i=0;
> > for(i=0; i<obj.size() ; i++)
> > {
> > sos.write(buf[i]);
> > }
> > // Close the object
> > obj.close();
> > }
> > rs.close();
> > }
> > ps.close();
> > mycon.close();
> >
> >
> > }
> > catch(SQLException sqex)
> > {
> > out.println(sqex.toString());
> > }
> > %>
> >
> >
> > the table is created like this:
> >
> > CREATE TABLE mytable(
> > pic oid,
> > month int2 NOT NULL,
> > year int2 NOT NULL,
> > PRIMARY KEY (month, year)
> > );
> >
> > I've searched all over the docs, asked all over IRC, and still does not
> > work. any ideas?
> >
> >
> >
> > ---------------------------(end of broadcast)---------------------------
> > TIP 4: Don't 'kill -9' the postmaster
> >
> >
>
>
>