Upload d'un fichier

 
package Servlet;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.sql.Blob;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
 
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
@WebServlet("/downloadFileServlet")
public class DownloadServlet extends HttpServlet {
 
    // size of byte buffer to send file
    private static final int BUFFER_SIZE = 4096;   
     
    // database connection settings
    private String dbURL = "jdbc:mysql://localhost:3306/bdd";
    private String dbUser = "root";
    private String dbPass = "";
     
    protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        // get upload id from URL's parameters
        int uploadId = Integer.parseInt(request.getParameter("idTemp"));
         
        Connection conn = null; // connection to the database
         
        try {
            // connects to the database
            DriverManager.registerDriver(new com.mysql.jdbc.Driver());
            conn = DriverManager.getConnection(dbURL, dbUser, dbPass);
 
            // queries the database
            String sql = "SELECT * FROM cours WHERE idTemp = ?";
            PreparedStatement statement = conn.prepareStatement(sql);
            statement.setInt(1, uploadId);
 
            ResultSet result = statement.executeQuery();
            if (result.next()) {
                // gets file name and file blob data
                String fileName = result.getString("title");
                Blob blob = result.getBlob("file");
                InputStream inputStream = blob.getBinaryStream();
                int fileLength = inputStream.available();
                 
                System.out.println("fileLength = " + fileLength);
 
                ServletContext context = getServletContext();
 
                // sets MIME type for the file download
                String mimeType = context.getMimeType(fileName);
                if (mimeType == null) {        
                    mimeType = "application/octet-stream";
                }              
                 
                // set content properties and header attributes for the response
                response.setContentType(mimeType);
                response.setContentLength(fileLength);
                String headerKey = "Content-Disposition";
                String headerValue = String.format("attachment; filename=\"%s\"", fileName);
                response.setHeader(headerKey, headerValue);
 
                // writes the file to the client
                OutputStream outStream = response.getOutputStream();
                 
                byte[] buffer = new byte[BUFFER_SIZE];
                int bytesRead = -1;
                 
                while ((bytesRead = inputStream.read(buffer)) != -1) {
                    outStream.write(buffer, 0, bytesRead);
                }
                 
                inputStream.close();
                outStream.close();             
            } else {
                // no file found
                response.getWriter().print("File not found for the id: " + uploadId);  
            }
        } catch (SQLException ex) {
            ex.printStackTrace();
            response.getWriter().print("SQL Error: " + ex.getMessage());
        } catch (IOException ex) {
            ex.printStackTrace();
            response.getWriter().print("IO Error: " + ex.getMessage());
        } finally {
            if (conn != null) {
                // closes the database connection
                try {
                    conn.close();
                } catch (SQLException ex) {
                    ex.printStackTrace();
                }
            }          
        }
    }
}

<%@page import="java.sql.ResultSet"%>
<%@page import="java.sql.Statement"%>
<%@page import="java.sql.DriverManager"%>
<%@page import="java.sql.Connection"%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>telechargement du cours</title>
    </head>
    <body>
        
        
        
        <br><br>
        <table border="1" width="254" cellpadding="5"/>
        <thead><th colspan="3"> Download      </th> 
</thead>
<tbody>
    <tr>
        <td>
<center><b>id</b></center><td>
<center><b>title</b></center></td>
<td><center><b>file</b></center>
        </td>
        
        
        
    </tr>
    
    <% 
         Class.forName("com.mysql.jdbc.Driver");
         
            Connection cn=DriverManager.getConnection("jdbc:mysql://localhost:3306/bdd","root","");
            
            String sql2="SELECT * FROM cours";
            Statement st=cn.createStatement();
            ResultSet rs= st.executeQuery(sql2);
            
            
            if(!rs.isBeforeFirst())
                
                
                
            {
                
            
            %>
            <tr>
                
                <td colspan="3"><center><% out.print("no file");%></center></td>
        </tr>
        <%
           }
           while(rs.next())   
{
    %>
    <tr>
        
        <td><center><% out.print(rs.getString("idTemp"));%>
           <td><center><% out.print(rs.getString("title"));%>  
               <form action="Download" method="GET">
                              
                                  
             
             
             <td> <input type="submit" value="Telecharger"</td>
          </form
               
        
        
    </tr> 
    <%}
           %>
                
                
                
             
    
</tbody>
</table>
           <% rs.close();
           st.close();
         cn.close();
         %>
    </body>
</html>