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| package com.pfe.slide;
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.URLDecoder;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* The Image servlet for serving from absolute path.
* @author BalusC
* @link http://balusc.blogspot.com/2007/04/imageservlet.html
*/
public class SlideServlet extends HttpServlet {
// Constants ----------------------------------------------------------------------------------
private static final int DEFAULT_BUFFER_SIZE = 10240; // 10KB.
// Properties ---------------------------------------------------------------------------------
private String imagePath;
// Actions ------------------------------------------------------------------------------------
public void init() throws ServletException {
// Define base path somehow. You can define it as init-param of the servlet.
this.imagePath = "\images";
// In a Windows environment with the Applicationserver running on the
// c: volume, the above path is exactly the same as "c:\images".
// In UNIX, it is just straightforward "/images".
// If you have stored files in the WebContent of a WAR, for example in the
// "/WEB-INF/images" folder, then you can retrieve the absolute path by:
// this.imagePath = getServletContext().getRealPath("/WEB-INF/images");
}
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
// Get requested image by path info.
String requestedImage = request.getPathInfo();
// je pense que cette ligne est inutile puisque je n'ai pas une image précise à récupérer
// Check if file name is actually supplied to the request URI.
if (requestedImage == null) {
// Do your thing if the image is not supplied to the request URI.
// Throw an exception, or send 404, or show default/warning image, or just ignore it.
response.sendError(HttpServletResponse.SC_NOT_FOUND); // 404.
return;
}
// Decode the file name (might contain spaces and on) and prepare file object.
File image = new File(imagePath, URLDecoder.decode(requestedImage, "UTF-8"));
// Check if file actually exists in filesystem.
if (!image.exists()) {
// Do your thing if the file appears to be non-existing.
// Throw an exception, or send 404, or show default/warning image, or just ignore it.
//response.sendError(HttpServletResponse.SC_NOT_FOUND); // 404
image = new File(imagePath, "default.gif");
return;
}
// Get content type by filename.
String contentType = getServletContext().getMimeType(image.getName());
// Check if file is actually an image (avoid download of other files by hackers!).
// For all content types, see: http://www.w3schools.com/media/media_mimeref.asp
if (contentType == null || !contentType.startsWith("image")) {
// Do your thing if the file appears not being a real image.
// Throw an exception, or send 404, or show default/warning image, or just ignore it.
response.sendError(HttpServletResponse.SC_NOT_FOUND); // 404.
return;
}
// Init servlet response.
response.reset();
response.setBufferSize(DEFAULT_BUFFER_SIZE);
response.setContentType(contentType);
response.setHeader("Content-Length", String.valueOf(image.length()));
response.setHeader("Content-Disposition", "inline; filename=\"" + image.getName() + "\"");
// Prepare streams.
BufferedInputStream input = null;
BufferedOutputStream output = null;
try {
// Open streams.
input = new BufferedInputStream(new FileInputStream(image), DEFAULT_BUFFER_SIZE);
output = new BufferedOutputStream(response.getOutputStream(), DEFAULT_BUFFER_SIZE);
// Write file contents to response.
byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
int length;
while ((length = input.read(buffer)) > 0) {
output.write(buffer, 0, length);
}
} finally {
// Gently close streams.
close(output);
close(input);
}
}
// Helpers (can be refactored to public utility class) ----------------------------------------
private static void close(Closeable resource) {
if (resource != null) {
try {
resource.close();
} catch (IOException e) {
// Do your thing with the exception. Print it, log it or mail it.
e.printStackTrace();
}
}
}
} |
affichage dynamique et périodique d'images dans une jsp à partir d'une servlet
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