Java编程实现服务器端支持断点续传的方法(可支持快车、迅雷)

import java.io.BufferedOutputStream;import java.io.File;import java.io.IOException;import java.io.RandomAccessFile;import java.io.UnsupportedEncodingException;import java.net.URI;import java.net.URISyntaxException;import java.net.URLDecoder;import javax.servlet.ServletException;import javax.servlet.ServletOutputStream;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import com.bsteel.cloud.storage.servlet.base.BaseServlet;import com.bsteel.cloud.storage.utils.FileUtil;/** * 文件下载(支持断点续传【迅雷/快车/旋风/Firefox/Chrome】) * @author jdkleo * */public class FileIoServlet extends BaseServlet { private static final long serialVersionUID = 1L; @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp)   throws ServletException, IOException {  this.doPost(req, resp); } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{  download(request,response); } /**  * 文件下载  * @param request  * @param response  * @throws UnsupportedEncodingException   */ private void download(HttpServletRequest request,HttpServletResponse response) throws UnsupportedEncodingException {  File downloadFile = getFile(request);  long pos = FileUtil.headerSetting(downloadFile, request, response);//  log.info("跳过"+pos);  ServletOutputStream os = null;   BufferedOutputStream out = null;  RandomAccessFile raf = null;  byte b[] = new byte[1024];//暂存容器  try {   os = response.getOutputStream();   out = new BufferedOutputStream(os);   raf = new RandomAccessFile(downloadFile, "r");   raf.seek(pos);   try {    int n = 0;    while ((n = raf.read(b, 0, 1024)) != -1) {     out.write(b, 0, n);    }    out.flush();   } catch(IOException ie) {   }  } catch (Exception e) {   log.error(e.getMessage(), e);  } finally {   if (out != null) {    try {     out.close();    } catch (IOException e) {     log.error(e.getMessage(), e);    }   }   if (raf != null) {    try {     raf.close();    } catch (IOException e) {     log.error(e.getMessage(), e);    }   }  } } private File getFile(HttpServletRequest request) throws UnsupportedEncodingException {  String uriStr = request.getParameter("uri");  if (null != uriStr){    uriStr = URLDecoder.decode(uriStr,"UTF-8");    if (uriStr.startsWith("file://")){     uriStr = uriStr.substring(7);     return new File(uriStr);    }else if (uriStr.startsWith("hbase://")){     try {      return new File(new URI(uriStr));     } catch (URISyntaxException e) {      log.error(e.getMessage(),e);     }    }  }  throw new RuntimeException("it's not a real uri"); }}

import java.io.File;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;/** * 文件处理工具 * @author jdkleo * */public class FileUtil { /**  * 断点续传支持  * @param file  * @param request  * @param response  * @return 跳过多少字节  */ public static long headerSetting(File file,HttpServletRequest request, HttpServletResponse response) {  long len = file.length();//文件长度  if ( null == request.getHeader("Range") ){   setResponse(new RangeSettings(len),file.getName(),response);   return 0;  }  String range = request.getHeader("Range").replaceAll("bytes=", "");  RangeSettings settings = getSettings(len,range);  setResponse(settings,file.getName(),response);  return settings.getStart(); } private static void setResponse(RangeSettings settings,String fileName, HttpServletResponse response) {  response.addHeader("Content-Disposition", "attachment; filename=/"" + IoUtil.toUtf8String(fileName) + "/"");  response.setContentType( IoUtil.setContentType(fileName));// set the MIME type.  if (!settings.isRange())  {   response.addHeader("Content-Length", String.valueOf(settings.getTotalLength()));  }  else  {   long start = settings.getStart();   long end = settings.getEnd();   long contentLength = settings.getContentLength();   response.setStatus(javax.servlet.http.HttpServletResponse.SC_PARTIAL_CONTENT);  response.addHeader("Content-Length", String.valueOf(contentLength));  String contentRange = new StringBuffer("bytes ").append(start).append("-").append(end).append("/").append(settings.getTotalLength()).toString();  response.setHeader("Content-Range", contentRange);  } } private static RangeSettings getSettings(long len, String range) {  long contentLength = 0;  long start = 0;  long end = 0;  if (range.startsWith("-"))// -500，最后500个  {    contentLength = Long.parseLong(range.substring(1));//要下载的量    end = len-1;    start = len - contentLength;  }  else if (range.endsWith("-"))//从哪个开始  {   start = Long.parseLong(range.replace("-", ""));   end = len -1;   contentLength = len - start;  }  else//从a到b  {   String[] se = range.split("-");   start = Long.parseLong(se[0]);   end = Long.parseLong(se[1]);   contentLength = end-start+1;  }  return new RangeSettings(start,end,contentLength,len); }}

public class RangeSettings{  private long start;  private long end;  private long contentLength;  private long totalLength;  private boolean range;  public RangeSettings(){   super();  }  public RangeSettings(long start, long end, long contentLength,long totalLength) {   this.start = start;   this.end = end;   this.contentLength = contentLength;   this.totalLength = totalLength;   this.range = true;  }  public RangeSettings(long totalLength) {   this.totalLength = totalLength;  }  public long getStart() {   return start;  }  public void setStart(long start) {   this.start = start;  }  public long getEnd() {   return end;  }  public void setEnd(long end) {   this.end = end;  }  public long getContentLength() {   return contentLength;  }  public void setContentLength(long contentLength) {   this.contentLength = contentLength;  }  public long getTotalLength() {   return totalLength;  }  public void setTotalLength(long totalLength) {   this.totalLength = totalLength;  }  public boolean isRange() {   return range;  }}

import java.io.InputStream;public class IoUtil { public static String setContentType(String returnFileName){  String contentType = "application/octet-stream";  if (returnFileName.lastIndexOf(".") < 0)   return contentType;  returnFileName = returnFileName.toLowerCase();  returnFileName = returnFileName.substring(returnFileName.lastIndexOf(".")+1);  if (returnFileName.equals("html") || returnFileName.equals("htm") || returnFileName.equals("shtml")){   contentType = "text/html";  } else if (returnFileName.equals("css")){   contentType = "text/css";  } else if (returnFileName.equals("xml")){   contentType = "text/xml";  } else if (returnFileName.equals("gif")){   contentType = "image/gif";  } else if (returnFileName.equals("jpeg") || returnFileName.equals("jpg")){   contentType = "image/jpeg";  } else if (returnFileName.equals("js")){   contentType = "application/x-javascript";  } else if (returnFileName.equals("atom")){   contentType = "application/atom+xml";  } else if (returnFileName.equals("rss")){   contentType = "application/rss+xml";  } else if (returnFileName.equals("mml")){   contentType = "text/mathml";   } else if (returnFileName.equals("txt")){   contentType = "text/plain";  } else if (returnFileName.equals("jad")){   contentType = "text/vnd.sun.j2me.app-descriptor";  } else if (returnFileName.equals("wml")){   contentType = "text/vnd.wap.wml";  } else if (returnFileName.equals("htc")){   contentType = "text/x-component";  } else if (returnFileName.equals("png")){   contentType = "image/png";  } else if (returnFileName.equals("tif") || returnFileName.equals("tiff")){   contentType = "image/tiff";  } else if (returnFileName.equals("wbmp")){   contentType = "image/vnd.wap.wbmp";  } else if (returnFileName.equals("ico")){   contentType = "image/x-icon";  } else if (returnFileName.equals("jng")){   contentType = "image/x-jng";  } else if (returnFileName.equals("bmp")){   contentType = "image/x-ms-bmp";  } else if (returnFileName.equals("svg")){   contentType = "image/svg+xml";  } else if (returnFileName.equals("jar") || returnFileName.equals("var") || returnFileName.equals("ear")){   contentType = "application/java-archive";  } else if (returnFileName.equals("doc")){   contentType = "application/msword";  } else if (returnFileName.equals("pdf")){   contentType = "application/pdf";  } else if (returnFileName.equals("rtf")){   contentType = "application/rtf";  } else if (returnFileName.equals("xls")){   contentType = "application/vnd.ms-excel";   } else if (returnFileName.equals("ppt")){   contentType = "application/vnd.ms-powerpoint";  } else if (returnFileName.equals("7z")){   contentType = "application/x-7z-compressed";  } else if (returnFileName.equals("rar")){   contentType = "application/x-rar-compressed";  } else if (returnFileName.equals("swf")){   contentType = "application/x-shockwave-flash";  } else if (returnFileName.equals("rpm")){   contentType = "application/x-redhat-package-manager";  } else if (returnFileName.equals("der") || returnFileName.equals("pem") || returnFileName.equals("crt")){   contentType = "application/x-x509-ca-cert";  } else if (returnFileName.equals("xhtml")){   contentType = "application/xhtml+xml";  } else if (returnFileName.equals("zip")){   contentType = "application/zip";  } else if (returnFileName.equals("mid") || returnFileName.equals("midi") || returnFileName.equals("kar")){   contentType = "audio/midi";  } else if (returnFileName.equals("mp3")){   contentType = "audio/mpeg";  } else if (returnFileName.equals("ogg")){   contentType = "audio/ogg";  } else if (returnFileName.equals("m4a")){   contentType = "audio/x-m4a";  } else if (returnFileName.equals("ra")){   contentType = "audio/x-realaudio";  } else if (returnFileName.equals("3gpp") || returnFileName.equals("3gp")){   contentType = "video/3gpp";  } else if (returnFileName.equals("mp4") ){   contentType = "video/mp4";  } else if (returnFileName.equals("mpeg") || returnFileName.equals("mpg") ){   contentType = "video/mpeg";  } else if (returnFileName.equals("mov")){   contentType = "video/quicktime";  } else if (returnFileName.equals("flv")){   contentType = "video/x-flv";  } else if (returnFileName.equals("m4v")){   contentType = "video/x-m4v";  } else if (returnFileName.equals("mng")){   contentType = "video/x-mng";  } else if (returnFileName.equals("asx") || returnFileName.equals("asf")){   contentType = "video/x-ms-asf";  } else if (returnFileName.equals("wmv")){   contentType = "video/x-ms-wmv";  } else if (returnFileName.equals("avi")){   contentType = "video/x-msvideo";  }  return contentType; } // UTF8转码 public static String toUtf8String(String s) {  StringBuffer sb = new StringBuffer();  int len = s.toCharArray().length;  for (int i = 0; i < len; i++) {   char c = s.charAt(i);   if (c >= 0 && c <= 255) {    sb.append(c);   } else {    byte[] b;    try {     b = Character.toString(c).getBytes("utf-8");    } catch (Exception ex) {     System.out.println(ex);     b = new byte[0];    }    for (int j = 0; j < b.length; j++) {     int k = b[j];     if (k < 0)      k += 256;     sb.append("%" + Integer.toHexString(k).toUpperCase());    }   }  }  String s_utf8 = sb.toString();  sb.delete(0, sb.length());  sb.setLength(0);  sb = null;  return s_utf8; } public static InputStream skipFully(InputStream in,long howMany)throws Exception{ long remainning = howMany; long len = 0; while(remainning>0){  len = in.skip(len);  remainning -= len; } return in; }}