JSP - ImageLoader from Database (BalusC code)

Question

ImageServlet
Firstly @ BalusC amazing code thanx
I have been playing with the ImageServlet and Wow.
It works perfectly
Here is my problem:
I want to load the image from my SQL Server 2000 database
but when I load the image it doesn't display and no errors occur
public class SQLImage{
  Connection conn = null;
  public SQLImage(){
    //init();
  public byte[] getImage(String name){
    try{
      PreparedStatement prepStat = conn.prepareStatement("SELECT [DATA] FROM [IMAGE_TABLE] WHERE [NAME] = '" + name + "'");
      ResultSet rs = prepStat.executeQuery();
      byte[] bytes = null;
      if(rs.hasNext())
        bytes = rs.getBytes(1);
      return bytes;
    }catch(Exception ex){
      ex.printStackTrace();
      return null;
  } The only thing I have changed on the ImageServlet is:
FROM
BufferedInputStream input = null;
BufferedOutputStream output = null;
        try {
            // Open image file.
            input = new BufferedInputStream(new FileInputStream(imageFile)); TO
BufferedInputStream input = null;
BufferedOutputStream output = null;
SQLImage sqlImage = new SQLImage();
        try {
            // Open image file.
            byte[] data = sqlImage.getImage(imageFileName);
            if(data == null){
              JOptionPane.showMessageDialog(null,"Null Value");
              return;
            input = new BufferedInputStream(new ByteArrayInputStream(data)); The Dialog is never displayed so that means that data contains a value
I take it the image data in the DB is the same as the image file
can anyone tell me what has changed and why it doesn't work?

Answer 1

DM_Is_SM
You know me to well,
I found the problem as suggested
        if (!imageFile.exists()) {
            // Do your thing if the file appears to be non-existing.
            // Throw an exception, or show default/warning image, or just ignore it.
            return;
        } as the file was located on the DB it will always return;.
I removed all the unnecessary code from ImageServlet
And this is the working code I am left with for ImageServlet
package mypackage;
import DataBase.SQL.SQLImage;
import java.io.ByteArrayInputStream;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.Closeable;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.net.URLConnection;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
* The Image servlet for retrieving image from Database
* @author BalusC - original
* @author gtRpr - Edited
* @link Orig - http://balusc.blogspot.com/2007/04/imageservlet.html
* @link Edit - http://forum.java.sun.com/thread.jspa?messageID=10340335
public class ImageServlet extends HttpServlet {
  protected void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException{
    String imageFileName = request.getParameter("file");
    Validate:
      imageFileName = imageFileName.replaceAll("'","<Apos">);
//    replace all ' chars with <Apos> when image is added to DB
//    and when retrieved from DB
//    Helps prevent SQL injection
//    EG:
//    "image?id=';TRUNCATE TABLE Image--"
//    Becomes
//    "image?id=<Apos>;TRUNCATE TABLE Image--"
    // Prepare streams.
    SQLImage sqlImage = new SQLImage();
    BufferedInputStream input = null;
    BufferedOutputStream output = null;
    try {
      // Open image file.
      input = new BufferedInputStream(new ByteArrayInputStream(sqlImage.ReadImage(imageFileName)));
      int contentLength = input.available();
      // Init servlet response.
      response.reset();
      response.setContentLength(contentLength);
      response.setHeader("Content-disposition", "inline; filename=\"" + imageFileName + "\"");
      output = new BufferedOutputStream(response.getOutputStream());
      // Write file contents to response.
      int data;
      while ((data = input.read()) != -1) {
        output.write(data);
      // Finalize task.
      output.flush();
    } catch (IOException e) {
      // Something went wrong?
      response.sendredirect("Error.jsp";);
    } finally {
      // Gently close streams.
      output.close();
      input.close();
}