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  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 >         {
> >           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
> > 
> > 
> 
> 
>