Uploading an Image

[Mary Cole]

I need to upload an image from the client machine into the database as blob using the JSPs.
Can somebody gimme a sample code how to proceed.
Thx in advance

[Bill Siggelkow]

Mary,
Basically you want to upload to a servlet not to a JSP. Consider the following client application code that receives the file name to upload and the URL of the servlet as arguments ...

import java.io.*;
import java.net.*;
public class FileUploader {
        
    public static void main( String[] args ) {
        String file = args[0];
        String urlAddress = args[1];
        BufferedInputStream bis = null;
        try {
            bis = new BufferedInputStream(new FileInputStream(file));
        }
        catch (FileNotFoundException fnfe) {
            System.err.println("File "+file+" not found.");
            System.exit(0);
        }            
                
        try {
            URL url = new URL(urlAddress);
            HttpURLConnection uc = (HttpURLConnection) url.openConnection();
            uc.setDoOutput(true);
            uc.setDoInput(true);
            uc.setAllowUserInteraction(false);
            
            BufferedOutputStream bos = new BufferedOutputStream(uc.getOutputStream());
            int bytesRead = 0;
            int bufferSize = 1024;
            byte[] buffer = new byte[bufferSize];
            while ((bytesRead = bis.read(buffer, 0, bufferSize)) != -1) {
                bos.write(buffer, 0, bytesRead);
                bos.flush();
            }
            bos.close();
            bis.close();
            
            // read the response
            String response = uc.getResponseMessage();
            System.out.println(response);
        }
        catch (Exception e) {
            System.err.println("Exception uploading file. "+e.getMessage());
        }
        
    }
}

Then you would write a servlet to read the input stream and then store the bytes to a file or possibly as a blob in a database as follows ...

import java.io.*;
import java.net.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class FileUploaderServlet extends HttpServlet {
  
    public void doGet(HttpServletRequest req, HttpServletResponse res)
                               throws ServletException, IOException {
        // Use a ServletOutputStream because we may pass binary information
        ServletOutputStream out = res.getOutputStream();
        res.setContentType("text/plain");  // sanity default
        
            // Get the input stream and process
            InputStream in = null;
            try {
                in = req.getInputStream();
// here you would process the input stream -- sending the data where need be
            }
            catch (IOException e) {
                res.sendError(res.SC_INTERNAL_SERVER_ERROR,
                  "Problem uploading file: " + e.getMessage());
            }
            finally {
                in.close();
            }
    }
    public void doPost(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException {
        doGet(req, res);
    }
}

[This message has been edited by Bill Siggelkow (edited December 04, 2001).]

[Mary Cole]

Hi Siggelkow,
My requirement is like this ----
I have a data entry screen on the browser.In the screen I have a field to upload the company logo .The company logo will be on the users machine.How do i read the image on the server side(using servlets/jsp) and update my database .
Can Ur sample program is flexible for this?
PL lemme know
Thx in advance

[Bill Siggelkow]

Mary,
No ... the program I gave you is a client-side application ... if you are uploading via an HTML form from a browser your servlet needs to process what is known as multipart form data ... It is non-trivial but you can use classes from oreilly to do help ... go to http://www.servlets.com
Also, you may want to look into the Struts web application framework http://jakarta.apache.org/struts

[Mary Cole]

Can U pl tell me how to update a blob into the database
I have a data entry screen on the browser.In the screen I have a field to upload the company logo .The company logo will be on the users machine.How do i read the image on the server side(using servlets/jsp) and update my database(i need to update the DB not insert into DB) .
Thx in advance