Re: JDBC + PostgreSQL + LargeObjects - Mailing list pgsql-jdbc

I would just change this:

...
int i=0;
for(i=0; i<obj.size() ; i++)
{
   out.write(buf[i]);
}
...

to this:

...
out.write(buf);
out.flush();
out.close();
...

Writing it out 1 byte at a time would be way too inefficient and is
probably why your CPU pegs.

Cheers,

Marc


Paulo Delgado wrote:

> Ok folks, now it works! thank you all!  (i'm using a servlet to avoid the white spaces)
> Now i have another problem, when the servlet is writing the bytes to the outputstream, the cpu load increases to
100%,i guess the problem is in the for() block, should i look for another way of doing this? or use perl? or what? 
>
> check it out:
>
> import javax.servlet.*;
> import java.io.*;
> import javax.servlet.http.*;
> import java.sql.*;
> import org.postgresql.largeobject.*;
>
> public class show_coctel extends HttpServlet
> {
>     public void doGet(HttpServletRequest request , HttpServletResponse response) throws ServletException, IOException

>     {
>     ServletOutputStream out = response.getOutputStream();
>     response.setContentType("image/jpeg");
>     try
>         {
>         Class.forName("org.postgresql.Driver");
>         }
>     catch(ClassNotFoundException cnfex)
>         {
>         cnfex.printStackTrace();
>         }
>     try
>         {
>         Connection mycon;
>         mycon= DriverManager.getConnection("jdbc:postgresql://localhost:5432/database", "username" , "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 cocteles 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++)
>                 {
>                 out.write(buf[i]);
>                 }
>             // Close the object
>             obj.close();
>             }
>             rs.close();
>         }
>         ps.close();
>         mycon.close();
>         }
>     catch(SQLException sqex)
>         {
>         out.println(sqex.toString());
>         }
>     }
> }
>
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>


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Marc P. Lavergne [wk:650-576-7978 hm:407-648-6996]
Senior Software Developer
Global Knowledge Management
Worldwide Support Technologies
Openwave Systems Inc.

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