Welcome to Nick Aiva 's blog!: Processing BLOBs via the ImageServlet

In this post an alternative code version to the traditional ImageServlet will be given, supplementing the one presented in the book named Oracle Fusion Developer Guide (p.409), by F.Nimphius and L.Munsinger and other official Oracle aces' and employees' blogs. This alternative version will use the EJB 3 way to get rid of the surplus database definition hard coded in the doGet() method. As an epilogue, further criticism will be provided, against using that technique of obtaining jdbc connections to the database.

Here is the modified code, with the original straight jdbc code commented out:



package actionbazaar.view.servlet;





import actionbazaar.buslogic.PlaceItem;



import java.io.BufferedInputStream;

import java.io.IOException;

import java.io.OutputStream;



import javax.naming.Context;

import javax.naming.InitialContext;

import javax.naming.NamingException;



import javax.servlet.ServletConfig;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;



import oracle.jbo.domain.BlobDomain;



import org.apache.log4j.Logger;





public class ImageServlet extends HttpServlet {

    private static final String CONTENT_TYPE = "image/jpg; charset=utf-8";

    @SuppressWarnings("compatibility:988932384557339885")

    private static final long serialVersionUID = 1L;

    private Logger logger = Logger.getLogger(this.getClass().getName());

    

    public void init(ServletConfig config) throws ServletException {

        super.init(config);

    }



    public void doGet(HttpServletRequest request,

                      HttpServletResponse response) throws ServletException,

                                                           IOException {

        response.setContentType(CONTENT_TYPE);

        Long itemId = new Long(request.getParameter("itemId"));

        if (logger.isDebugEnabled())

            logger.debug("itemId = " + itemId);

        try {

                Context context = new InitialContext();

                PlaceItem placeItem = (PlaceItem)context.lookup("ejb3inaction-Model-PlaceItem#actionbazaar.buslogic.PlaceItem");

                byte[] image  = placeItem.getImageByItemId(itemId);



            if (image != null) {

                BlobDomain bld = new BlobDomain(image);



                OutputStream os = response.getOutputStream();

                BufferedInputStream in =  new BufferedInputStream(bld.getBinaryStream());

                int b;

                byte[] buffer = new byte[10240];



                while ((b = in.read(buffer, 0, 10240)) != -1) {

                    os.write(buffer, 0, b);

                }

                os.close();

            } else {

                    if (logger.isDebugEnabled())

                        logger.debug("No  image exists yet for itemId: " + itemId);

                }

        } catch (NamingException e){

            e.printStackTrace();    

        }

        catch (IOException e){

            e.printStackTrace();    

        }

       /*

        Connection conn = null;





        try {

            Context ctx = new InitialContext();

//Datasource as defined in <res-ref-name> element of weblogic.xml

            DataSource ds =

                (DataSource)ctx.lookup("jdbc/ActionBazaarEJB3inActionDS");



            conn = ds.getConnection();

            PreparedStatement statement =

                conn.prepareStatement("SELECT IMAGE " +

                                      " FROM ITEMS" +

                                    " WHERE ITEM_ID= ? ");

            statement.setInt(1, new Integer(itemId));

            ResultSet rs = statement.executeQuery();



            if (rs.next()) {

                Blob blob = rs.getBlob("IMAGE");



                BufferedInputStream in =

                    new BufferedInputStream(blob.getBinaryStream());

                int b;

                byte[] buffer = new byte[10240];



                while ((b = in.read(buffer, 0, 10240)) != -1) {

                    os.write(buffer, 0, b);

                }

                os.close();



            }

        } catch (Exception e) {

            e.printStackTrace();

        } finally {

            try {

                if (conn != null) {



                    conn.close();

                }



            } catch (SQLException sqle) {

                sqle.printStackTrace();



            }



        }*/

       

    }



   }