package hall; import java.io.*; import javax.servlet.*; import javax.servlet.http.*; /** Demonstrates a servlet translating paths and reading files. *

* Part of tutorial on servlets and JSP that appears at * http://www.apl.jhu.edu/~hall/java/Servlet-Tutorial/ * 1999 Marty Hall; may be freely used or adapted. */ public class FileRetriever extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String path = getServletContext().getRealPath("/"); String file = request.getParameter("file"); if (file == null) sendError(response, "You must supply a 'file' parameter."); else file = path + file; try { response.setContentType("text/html"); PrintWriter out = response.getWriter(); String title = "Reading Files from Servlets"; out.println(ServletUtilities.headWithTitle(title) + "\n" + "

" + title + "

\n" + "

" + file + "

\n" + ""); BufferedInputStream in = new BufferedInputStream(new FileInputStream(file)); int nextByte; while((nextByte = in.read()) != -1) out.write(nextByte); in.close(); out.println(""); } catch(FileNotFoundException fnfe) { sendError(response, "No such file in: " + path); } catch(IOException ioe) { sendError(response, "IOException: " + ioe); } } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } private void sendError(HttpServletResponse response, String message) throws IOException { response.sendError(response.SC_NOT_FOUND, message); } }