file downloader for image downloading not upto the limit....

[prasad guna]

i create file downloader its downloading perfectely but not an upto the total length

   import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
 
public class dlservlet extends HttpServlet {
 String filepath;
    @Override
 public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        try {
String filename=request.getParameter("name");           
String cat = request.getParameter("category");
if(cat.equals("themes")){
filepath="http://localhost:8080/WebApplication1/image/"+filename;
out.println(filepath);
}
else if(cat.equals("wallpapers")){
filepath="http://localhost:8080/WebApplication1/image/"+filename;    
out.println(filepath);
}
else if(cat.equals("games")){
filepath="http://localhost:8080/WebApplication1/image/"+filename;    
out.println(filepath);
}
File f = new File(filepath);
response.setContentType("image/jpeg"); 
response.setHeader("Content-Disposition", "attachment; filename= \""+filename+"\""); 
FileInputStream fin = new FileInputStream(f);
int size=fin.available(); 
response.setContentLength(fin.available()); 

byte[] ab = new byte[size];
OutputStream os = response.getOutputStream();
int bytesread;
do{
bytesread = fin.read(ab,0,size);
if(bytesread >-1)
os.write(ab,0,bytesread);
}while(bytesread >-1);
fin.close();
os.flush();
os.close();
} finally { 
out.close();
        }
    } 
} 

please help me as soon....

[Rob Spoor]

Available Doesn't Do What You Think It Does.

Also some corrections to your code:
1) check if cat is null, or you will get into problems.

2) you can't use File with an http:// URL. Instead, you should use the following code:

File f = new File(getServletContext().getRealPath("/image/" + filename));

ServletContext's getRealPath method will translate the path, relative to your web application, to a real file path. In this case, it would be C:\<Path to Tomcat>\webapps\WebApplication1/image/<filename> on Windows.

3) don't mix response.getWriter() and response.getOutputStream(). Simply remove setting the first content type, and every reference to out.

4) your code is vulnerable to path injection. Suppose the filename is ..\..\..\..\..\..\..\..\..\..\Windows\win.ini - that could allow the user to retrieve C:\Windows\win.ini. With other examples, the user could retrieve important system files. Make sure that you validate the file name first.