I finally found an implementation of a servlet, this site has the class and also makes a wide explanation for better understanding read the article. All the job is made by the servlet, here is the code:
package org.onedevelopment.servlet; /* * net/balusc/webapp/FileServlet.java * * Copyright (C) 2009 BalusC * * This program is free software: you can redistribute it and/or modify it under the terms of the * GNU Lesser General Public License as published by the Free Software Foundation, either version 3 * of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without * even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License along with this library. * If not, see <http://www.gnu.org/licenses/>. */ import java.io.Closeable; import java.io.File; import java.io.IOException; import java.io.OutputStream; import java.io.RandomAccessFile; import java.net.URLDecoder; import java.util.ArrayList; import java.util.Arrays; import java.util.List; import java.util.zip.GZIPOutputStream; import javax.servlet.ServletException; import javax.servlet.ServletOutputStream; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; /** * A file servlet supporting resume of downloads and client-side caching and GZIP of text content. * This servlet can also be used for images, client-side caching would become more efficient. * This servlet can also be used for text files, GZIP would decrease network bandwidth. * * @author BalusC * @link http://balusc.blogspot.com/2009/02/fileservlet-supporting-resume-and.html */ public class FileServlet extends HttpServlet { // Constants ---------------------------------------------------------------------------------- /** * */ private static final long serialVersionUID = 1L; private static final int DEFAULT_BUFFER_SIZE = 10240; // ..bytes = 10KB. private static final long DEFAULT_EXPIRE_TIME = 604800000L; // ..ms = 1 week. private static final String MULTIPART_BOUNDARY = "MULTIPART_BYTERANGES"; // Properties --------------------------------------------------------------------------------- private String basePath; // Actions ------------------------------------------------------------------------------------ /** * Initialize the servlet. * @see HttpServlet#init(). */ public void init() throws ServletException { // Get base path (path to get all resources from) as init parameter. this.basePath = getInitParameter("basePath"); // Validate base path. if (this.basePath == null) { throw new ServletException("FileServlet init param 'basePath' is required."); } else { File path = new File(this.basePath); if (!path.exists()) { throw new ServletException("FileServlet init param 'basePath' value '" + this.basePath + "' does actually not exist in file system."); } else if (!path.isDirectory()) { throw new ServletException("FileServlet init param 'basePath' value '" + this.basePath + "' is actually not a directory in file system."); } else if (!path.canRead()) { throw new ServletException("FileServlet init param 'basePath' value '" + this.basePath + "' is actually not readable in file system."); } } } /** * Process HEAD request. This returns the same headers as GET request, but without content. * @see HttpServlet#doHead(HttpServletRequest, HttpServletResponse). */ protected void doHead(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // Process request without content. processRequest(request, response, false); } /** * Process GET request. * @see HttpServlet#doGet(HttpServletRequest, HttpServletResponse). */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // Process request with content. processRequest(request, response, true); } /** * Process the actual request. * @param request The request to be processed. * @param response The response to be created. * @param content Whether the request body should be written (GET) or not (HEAD). * @throws IOException If something fails at I/O level. */ private void processRequest (HttpServletRequest request, HttpServletResponse response, boolean content) throws IOException { // Validate the requested file ------------------------------------------------------------ // Get requested file by path info. String requestedFile = request.getPathInfo(); // Check if file is actually supplied to the request URL. if (requestedFile == null) { // Do your thing if the file is not supplied to the request URL. // Throw an exception, or send 404, or show default/warning page, or just ignore it. response.sendError(HttpServletResponse.SC_NOT_FOUND); return; } // URL-decode the file name (might contain spaces and on) and prepare file object. File file = new File(basePath, URLDecoder.decode(requestedFile, "UTF-8")); // Check if file actually exists in filesystem. if (!file.exists()) { // Do your thing if the file appears to be non-existing. // Throw an exception, or send 404, or show default/warning page, or just ignore it. response.sendError(HttpServletResponse.SC_NOT_FOUND); return; } // Prepare some variables. The ETag is an unique identifier of the file. String fileName = file.getName(); long length = file.length(); long lastModified = file.lastModified(); String eTag = fileName + "_" + length + "_" + lastModified; long expires = System.currentTimeMillis() + DEFAULT_EXPIRE_TIME; // Validate request headers for caching --------------------------------------------------- // If-None-Match header should contain "*" or ETag. If so, then return 304. String ifNoneMatch = request.getHeader("If-None-Match"); if (ifNoneMatch != null && matches(ifNoneMatch, eTag)) { response.setStatus(HttpServletResponse.SC_NOT_MODIFIED); response.setHeader("ETag", eTag); // Required in 304. response.setDateHeader("Expires", expires); // Postpone cache with 1 week. return; } // If-Modified-Since header should be greater than LastModified. If so, then return 304. // This header is ignored if any If-None-Match header is specified. long ifModifiedSince = request.getDateHeader("If-Modified-Since"); if (ifNoneMatch == null && ifModifiedSince != -1 && ifModifiedSince + 1000 > lastModified) { response.setStatus(HttpServletResponse.SC_NOT_MODIFIED); response.setHeader("ETag", eTag); // Required in 304. response.setDateHeader("Expires", expires); // Postpone cache with 1 week. return; } // Validate request headers for resume ---------------------------------------------------- // If-Match header should contain "*" or ETag. If not, then return 412. String ifMatch = request.getHeader("If-Match"); if (ifMatch != null && !matches(ifMatch, eTag)) { response.sendError(HttpServletResponse.SC_PRECONDITION_FAILED); return; } // If-Unmodified-Since header should be greater than LastModified. If not, then return 412. long ifUnmodifiedSince = request.getDateHeader("If-Unmodified-Since"); if (ifUnmodifiedSince != -1 && ifUnmodifiedSince + 1000 <= lastModified) { response.sendError(HttpServletResponse.SC_PRECONDITION_FAILED); return; } // Validate and process range ------------------------------------------------------------- // Prepare some variables. The full Range represents the complete file. Range full = new Range(0, length - 1, length); List<Range> ranges = new ArrayList<Range>(); // Validate and process Range and If-Range headers. String range = request.getHeader("Range"); if (range != null) { // Range header should match format "bytes=n-n,n-n,n-n...". If not, then return 416. if (!range.matches("^bytes=\\d*-\\d*(,\\d*-\\d*)*$")) { response.setHeader("Content-Range", "bytes */" + length); // Required in 416. response.sendError(HttpServletResponse.SC_REQUESTED_RANGE_NOT_SATISFIABLE); return; } // If-Range header should either match ETag or be greater then LastModified. If not, // then return full file. String ifRange = request.getHeader("If-Range"); if (ifRange != null && !ifRange.equals(eTag)) { try { long ifRangeTime = request.getDateHeader("If-Range"); // Throws IAE if invalid. if (ifRangeTime != -1 && ifRangeTime + 1000 < lastModified) { ranges.add(full); } } catch (IllegalArgumentException ignore) { ranges.add(full); } } // If any valid If-Range header, then process each part of byte range. if (ranges.isEmpty()) { for (String part : range.substring(6).split(",")) { // Assuming a file with length of 100, the following examples returns bytes at: // 50-80 (50 to 80), 40- (40 to length=100), -20 (length-20=80 to length=100). long start = sublong(part, 0, part.indexOf("-")); long end = sublong(part, part.indexOf("-") + 1, part.length()); if (start == -1) { start = length - end; end = length - 1; } else if (end == -1 || end > length - 1) { end = length - 1; } // Check if Range is syntactically valid. If not, then return 416. if (start > end) { response.setHeader("Content-Range", "bytes */" + length); // Required in 416. response.sendError(HttpServletResponse.SC_REQUESTED_RANGE_NOT_SATISFIABLE); return; } // Add range. ranges.add(new Range(start, end, length)); } } } // Prepare and initialize response -------------------------------------------------------- // Get content type by file name and set default GZIP support and content disposition. String contentType = getServletContext().getMimeType(fileName); boolean acceptsGzip = false; String disposition = "inline"; // If content type is unknown, then set the default value. // For all content types, see: http://www.w3schools.com/media/media_mimeref.asp // To add new content types, add new mime-mapping entry in web.xml. if (contentType == null) { contentType = "application/octet-stream"; } // If content type is text, then determine whether GZIP content encoding is supported by // the browser and expand content type with the one and right character encoding. if (contentType.startsWith("text")) { String acceptEncoding = request.getHeader("Accept-Encoding"); acceptsGzip = acceptEncoding != null && accepts(acceptEncoding, "gzip"); contentType += ";charset=UTF-8"; } // Else, expect for images, determine content disposition. If content type is supported by // the browser, then set to inline, else attachment which will pop a 'save as' dialogue. else if (!contentType.startsWith("image")) { String accept = request.getHeader("Accept"); disposition = accept != null && accepts(accept, contentType) ? "inline" : "attachment"; } // Initialize response. response.reset(); response.setBufferSize(DEFAULT_BUFFER_SIZE); response.setHeader("Content-Disposition", disposition + ";filename=\"" + fileName + "\""); response.setHeader("Accept-Ranges", "bytes"); response.setHeader("ETag", eTag); response.setDateHeader("Last-Modified", lastModified); response.setDateHeader("Expires", expires); // Send requested file (part(s)) to client ------------------------------------------------ // Prepare streams. RandomAccessFile input = null; OutputStream output = null; try { // Open streams. input = new RandomAccessFile(file, "r"); output = response.getOutputStream(); if (ranges.isEmpty() || ranges.get(0) == full) { // Return full file. Range r = full; response.setContentType(contentType); response.setHeader("Content-Range", "bytes " + r.start + "-" + r.end + "/" + r.total); if (content) { if (acceptsGzip) { // The browser accepts GZIP, so GZIP the content. response.setHeader("Content-Encoding", "gzip"); output = new GZIPOutputStream(output, DEFAULT_BUFFER_SIZE); } else { // Content length is not directly predictable in case of GZIP. // So only add it if there is no means of GZIP, else browser will hang. response.setHeader("Content-Length", String.valueOf(r.length)); } // Copy full range. copy(input, output, r.start, r.length); } } else if (ranges.size() == 1) { // Return single part of file. Range r = ranges.get(0); response.setContentType(contentType); response.setHeader("Content-Range", "bytes " + r.start + "-" + r.end + "/" + r.total); response.setHeader("Content-Length", String.valueOf(r.length)); response.setStatus(HttpServletResponse.SC_PARTIAL_CONTENT); // 206. if (content) { // Copy single part range. copy(input, output, r.start, r.length); } } else { // Return multiple parts of file. response.setContentType("multipart/byteranges; boundary=" + MULTIPART_BOUNDARY); response.setStatus(HttpServletResponse.SC_PARTIAL_CONTENT); // 206. if (content) { // Cast back to ServletOutputStream to get the easy println methods. ServletOutputStream sos = (ServletOutputStream) output; // Copy multi part range. for (Range r : ranges) { // Add multipart boundary and header fields for every range. sos.println(); sos.println("--" + MULTIPART_BOUNDARY); sos.println("Content-Type: " + contentType); sos.println("Content-Range: bytes " + r.start + "-" + r.end + "/" + r.total); // Copy single part range of multi part range. copy(input, output, r.start, r.length); } // End with multipart boundary. sos.println(); sos.println("--" + MULTIPART_BOUNDARY + "--"); } } } finally { // Gently close streams. close(output); close(input); } } // Helpers (can be refactored to public utility class) ---------------------------------------- /** * Returns true if the given accept header accepts the given value. * @param acceptHeader The accept header. * @param toAccept The value to be accepted. * @return True if the given accept header accepts the given value. */ private static boolean accepts(String acceptHeader, String toAccept) { String[] acceptValues = acceptHeader.split("\\s*(,|;)\\s*"); Arrays.sort(acceptValues); return Arrays.binarySearch(acceptValues, toAccept) > -1 || Arrays.binarySearch(acceptValues, toAccept.replaceAll("/.*$", "/*")) > -1 || Arrays.binarySearch(acceptValues, "*/*") > -1; } /** * Returns true if the given match header matches the given value. * @param matchHeader The match header. * @param toMatch The value to be matched. * @return True if the given match header matches the given value. */ private static boolean matches(String matchHeader, String toMatch) { String[] matchValues = matchHeader.split("\\s*,\\s*"); Arrays.sort(matchValues); return Arrays.binarySearch(matchValues, toMatch) > -1 || Arrays.binarySearch(matchValues, "*") > -1; } /** * Returns a substring of the given string value from the given begin index to the given end * index as a long. If the substring is empty, then -1 will be returned * @param value The string value to return a substring as long for. * @param beginIndex The begin index of the substring to be returned as long. * @param endIndex The end index of the substring to be returned as long. * @return A substring of the given string value as long or -1 if substring is empty. */ private static long sublong(String value, int beginIndex, int endIndex) { String substring = value.substring(beginIndex, endIndex); return (substring.length() > 0) ? Long.parseLong(substring) : -1; } /** * Copy the given byte range of the given input to the given output. * @param input The input to copy the given range to the given output for. * @param output The output to copy the given range from the given input for. * @param start Start of the byte range. * @param length Length of the byte range. * @throws IOException If something fails at I/O level. */ private static void copy(RandomAccessFile input, OutputStream output, long start, long length) throws IOException { byte[] buffer = new byte[DEFAULT_BUFFER_SIZE]; int read; if (input.length() == length) { // Write full range. while ((read = input.read(buffer)) > 0) { output.write(buffer, 0, read); } } else { // Write partial range. input.seek(start); long toRead = length; while ((read = input.read(buffer)) > 0) { if ((toRead -= read) > 0) { output.write(buffer, 0, read); } else { output.write(buffer, 0, (int) toRead + read); break; } } } } /** * Close the given resource. * @param resource The resource to be closed. */ private static void close(Closeable resource) { if (resource != null) { try { resource.close(); } catch (IOException ignore) { // Ignore IOException. If you want to handle this anyway, it might be useful to know // that this will generally only be thrown when the client aborted the request. } } } // Inner classes ------------------------------------------------------------------------------ /** * This class represents a byte range. */ protected class Range { long start; long end; long length; long total; /** * Construct a byte range. * @param start Start of the byte range. * @param end End of the byte range. * @param total Total length of the byte source. */ public Range(long start, long end, long total) { this.start = start; this.end = end; this.length = end - start + 1; this.total = total; } } }
Of course it is important to define in the web.xml our servlet:
<servlet> <servlet-name>fileServlet</servlet-name> <servlet-class>org.onedevelopment.servlet.FileServlet</servlet-class> <init-param> <param-name>basePath</param-name> <param-value>c:/Temp</param-value> </init-param> </servlet> <servlet-mapping> <servlet-name>fileServlet</servlet-name> <url-pattern>/files/*</url-pattern> </servlet-mapping>
The most important point here is to define the physical path of the multimedia files, in the example is "c:/temp", This is the path to where the servlet will look for files to load and return the output to the client.
<param-value>c:/Temp</param-value>
On the client we can request the media files in the file "index.jsp" in this way, using the multimedia tag of HTML5:
<video width="320" height="240" controls> <source src="files/music.mp3" type="audio/mpeg"> Your browser does not support the audio element. </video> <br/> <video width="620" height="440" controls> <source src="files/video.mp4" type="video/mp4"> Your browser does not support the audio element. </video>
Finally the result would be something like this:
I hope this help, the codes can be downloaded here.
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