import java.io.IOException;
    import java.io.InputStream;
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.PreparedStatement;
    import java.sql.SQLException;



    import javax.servlet.ServletException;
    import javax.servlet.annotation.MultipartConfig;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import javax.servlet.http.Part;

    @SuppressWarnings("serial")
    @WebServlet("/upload")
    @MultipartConfig(maxFileSize = 16177215)
    public class FileUploadDBServlet extends HttpServlet {


         private String dbURL = "jdbc:oracle:thin:@localhost:1521:xe";
            private String dbUser = "system";
            private String dbPass = "system";

        protected void doPost(HttpServletRequest request,
                HttpServletResponse response) throws ServletException, IOException {

            String fileId = request.getParameter("fileId");
            String fieldName = request.getParameter("fieldName");

            InputStream inputStream = null;


            Part filePart = request.getPart("fileData");
            if (filePart != null) {

                System.out.println(filePart.getName());
                System.out.println(filePart.getSize());
                System.out.println(filePart.getContentType().equals("application/pdf"));

                // obtains input stream of the upload file
                inputStream = filePart.getInputStream();
            }

            Connection conn = null;
            String message = null;

            try {
                // connects to the database
                DriverManager.registerDriver(new oracle.jdbc.driver.OracleDriver());
                conn = DriverManager.getConnection(dbURL, dbUser, dbPass);

                // constructs SQL statement
                String sql = "INSERT INTO filetable (fileId, fieldName, fileData) values (?, ?, ?)";
                PreparedStatement statement = conn.prepareStatement(sql);
                statement.setString(1, fileId);
                statement.setString(2, fieldName);

                if (inputStream != null) {
                    // fetches input stream of the upload file for the blob column
                    statement.setBlob(3, inputStream);
                }

                // sends the statement to the database server
                int row = statement.executeUpdate();
                if (row > 0) {
                    message = "File uploaded and saved into database";
                }
            } catch (SQLException ex) {
                message = "ERROR: " + ex.getMessage();
                ex.printStackTrace();
            } finally {
                if (conn != null) {
                    // closes the database connection
                    try {
                        conn.close();
                    } catch (SQLException ex) {
                        ex.printStackTrace();
                    }
                }
                // sets the message in request scope
                request.setAttribute("Message", message);

                // forwards to the message page
                getServletContext().getRequestDispatcher("/Message.jsp").forward(request, response);
            }
        }
    }