1 此类核心续传servlet  2 |||||||||||||||||||  3   4   5 import java.io.BufferedOutputStream;  6 import java.io.File;  7 import java.io.IOException;  8 import java.io.OutputStream;  9 import java.io.RandomAccessFile; 10 import java.util.concurrent.ConcurrentSkipListMap; 11 import javax.servlet.ServletException; 12 import javax.servlet.http.HttpServlet; 13 import javax.servlet.http.HttpServletRequest; 14 import javax.servlet.http.HttpServletResponse; 15 import org.apache.commons.logging.Log; 16 import org.apache.commons.logging.LogFactory; 17 import org.springframework.util.Assert; 18  19 //HTTP 断点续传 demo（客户端测试工具：快车、迅雷） 20 public class MyHttpDownloadServlet extends HttpServlet { 21      private static final long serialVersionUID = 1L; 22      final static Log log = LogFactory.getLog(ArcSyncHttpDownloadServlet. class); 23  24      @Override 25      protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { 26             this.doPost(req, resp); 27      } 28  29      @Override 30      protected void doPost(HttpServletRequest request, HttpServletResponse response) { 31            String name = request. getParameter("filename"); 32  33             try { 34                  log.info( "请求下载的连接地址为：" + request.getRequestURL() + "?" + request.getQueryString()); 35                 Assert. hasText(name); 36            } catch (IllegalArgumentException e) { 37                  log.error( "请求下载的文件名参数为空！" ); 38                  return; 39            } 40            String path = "D:/Install/" + name; 41             log.info( "文件拼装路径：" + path); 42            File downloadFile = new File(path); 43             if (downloadFile.exists()) { 44                  if (downloadFile.isFile()) { 45                       if (downloadFile.length() > 0) { 46                      } else { 47                             log.info( "请求下载的文件是一个空文件" ); 48                             return; 49                      } 50                       if (!downloadFile.canRead()) { 51                             log.info( "请求下载的文件不是一个可读的文件" ); 52                             return; 53                      } else { 54                      } 55                 } else { 56                       log.info( "请求下载的文件是一个文件夹" ); 57                       return; 58                 } 59            } else { 60                  log.info( "请求下载的文件不存在！" ); 61                  return; 62            } 63  64             long fileLength = downloadFile.length(); // 记录文件大小 65             long pastLength = 0; // 记录已下载文件大小 66             int rangeSwitch = 0; // 0：从头开始的全文下载；1：从某字节开始的下载（bytes=27000-）；2：从某字节开始到某字节结束的下载（bytes=27000-39000） 67             long toLength = 0; // 记录客户端需要下载的字节段的最后一个字节偏移量（比如bytes=27000-39000，则这个值是为39000） 68             long contentLength = 0; // 客户端请求的字节总量 69            String rangeBytes = ""; // 记录客户端传来的形如“bytes=27000-”或者“bytes=27000-39000”的内容 70            RandomAccessFile raf = null; // 负责读取数据 71            OutputStream os = null; // 写出数据 72            OutputStream out = null; // 缓冲 73             byte b[] = new byte[1024]; // 暂存容器 74  75             if (request.getHeader( "Range") != null) { // 客户端请求的下载的文件块的开始字节 76                 response.setStatus(javax.servlet.http.HttpServletResponse. SC_PARTIAL_CONTENT); 77                  log.info( "request.getHeader(\"Range\")=" + request.getHeader("Range" )); 78                 rangeBytes = request.getHeader("Range" ).replaceAll("bytes=" , "" ); 79                  if (rangeBytes.indexOf( '-') == rangeBytes.length() - 1) {
   // bytes=969998336- 80                      rangeSwitch = 1; 81                      rangeBytes = rangeBytes.substring(0, rangeBytes.indexOf('-')); 82                      pastLength = Long.parseLong(rangeBytes.trim()); 83                      contentLength = fileLength - pastLength; // 客户端请求的是 969998336 之后的字节 84                 } else { // bytes=1275856879-1275877358 85                      rangeSwitch = 2; 86                      String temp0 = rangeBytes.substring(0, rangeBytes.indexOf('-')); 87                      String temp2 = rangeBytes.substring(rangeBytes.indexOf('-' ) + 1, rangeBytes.length()); 88                      pastLength = Long. parseLong(temp0.trim()); // bytes=1275856879-1275877358，从第 1275856879 个字节开始下载 89                      toLength = Long. parseLong(temp2); // bytes=1275856879-1275877358，到第 1275877358 个字节结束 90                      contentLength = toLength - pastLength; // 客户端请求的是 1275856879-1275877358 之间的字节 91                 } 92            } else { // 从开始进行下载 93                 contentLength = fileLength; // 客户端要求全文下载 94            } 95  96             /** 97             * 如果设设置了Content -Length，则客户端会自动进行多线程下载。如果不希望支持多线程，则不要设置这个参数。 响应的格式是: Content - Length: [文件的总大小] - [客户端请求的下载的文件块的开始字节] ServletActionContext.getResponse().setHeader("Content- Length", new Long(file.length() - p).toString()); 98             */ 99            response.reset(); // 告诉客户端允许断点续传多线程连接下载,响应的格式是:Accept-Ranges: bytes100            response.setHeader( "Accept-Ranges", "bytes" );// 如果是第一次下,还没有断点续传,状态是默认的 200,无需显式设置;响应的格式是:HTTP/1.1 200 OK101             if (pastLength != 0) {102                  // 不是从最开始下载,103                  // 响应的格式是:104                  // Content-Range: bytes [文件块的开始字节]-[文件的总大小 - 1]/[文件的总大小]105                  log.info( "----------------------------不是从开始进行下载！服务器即将开始断点续传..." );106                  switch (rangeSwitch) {107                  case 1: { // 针对 bytes=27000- 的请求108                      String contentRange = new StringBuffer("bytes ").append(new Long(pastLength).toString()).append("-" ).append(new Long(fileLength - 1).toString()).append("/" ).append(new Long(fileLength).toString()).toString();109                      response.setHeader( "Content-Range", contentRange);110                       break;111                 }112                  case 2: { // 针对 bytes=27000-39000 的请求113                      String contentRange = rangeBytes + "/" + new Long(fileLength).toString();114                      response.setHeader( "Content-Range", contentRange);115                       break;116                 }117                  default: {118                       break;119                 }120                 }121            } else {122                  // 是从开始下载123                  log.info( "----------------------------是从开始进行下载！" );124            }125 126             try {127                 response.addHeader( "Content-Disposition", "attachment; filename=\"" + downloadFile.getName() + "\"");128                 response.setContentType(CommonUtil. setContentType(downloadFile.getName())); // set the MIME type.129                 response.addHeader( "Content-Length", String.valueOf(contentLength));130                 os = response.getOutputStream();131                 out = new BufferedOutputStream(os);132                 raf = new RandomAccessFile(downloadFile, "r");133                  try {134                       switch (rangeSwitch) {135                       case 0: { // 普通下载，或者从头开始的下载136                             // 同1137                      }138                       case 1: { // 针对 bytes=27000- 的请求139                            raf.seek(pastLength); // 形如 bytes=969998336- 的客户端请求，跳过 969998336 个字节140                             int n = 0;141                             while ((n = raf.read(b, 0, 1024)) != -1) {142                                 out.write(b, 0, n);143                            }144                             break;145                      }146                       case 2: { // 针对 bytes=27000-39000 的请求147                            raf.seek(pastLength); // 形如 bytes=1275856879-1275877358 的客户端请求，找到第 1275856879 个字节148                             int n = 0;149                             long readLength = 0; // 记录已读字节数150                             while (readLength <= contentLength - 1024) {
   // 大部分字节在这里读取151                                 n = raf.read(b, 0, 1024);152                                 readLength += 1024;153                                 out.write(b, 0, n);154                            }155                             if (readLength <= contentLength) { // 余下的不足 1024 个字节在这里读取156                                 n = raf.read(b, 0, ( int) (contentLength - readLength));157                                 out.write(b, 0, n);158                            }159                             break;160                      }161                       default: {162                             break;163                      }164                      }165                      out.flush();166                       log.info( "------------------------------下载结束" );167                 } catch (IOException ie) {168                       /**169                       * 在写数据的时候， 对于 ClientAbortException 之类的异常， 是因为客户端取消了下载，而服务器端继续向浏览器写入数据时， 抛出这个异常，这个是正常的。 尤其是对于迅雷这种吸血的客户端软件， 明明已经有一个线程在读取 bytes=1275856879-1275877358， 如果短时间内没有读取完毕，迅雷会再启第二个、第三个。。。线程来读取相同的字节段， 直到有一个线程读取完毕，迅雷会 KILL 掉其他正在下载同一字节段的线程， 强行中止字节读出，造成服务器抛 ClientAbortException。 所以，我们忽略这种异常170                       */171                       // ignore172                       log.info( "#提醒# 向客户端传输时出现IO异常，但此异常是允许的的，有可能客户端取消了下载，导致此异常，不用关心！" );173                 }174            } catch (Exception e) {175                  log.error(e.getMessage(), e);176            } finally {177                  if (out != null) {178                       try {179                            out.close();180                      } catch (IOException e) {181                             log.error(e.getMessage(), e);182                      }183                 }184                  if (raf != null) {185                       try {186                            raf.close();187                      } catch (IOException e) {188                             log.error(e.getMessage(), e);189                      }190                 }191            }192      }193 }

 

1 此类是根据扩展名返回ContentType类型  2 ||||||||||||||||||||||||||||||||||||||  3   4   5 public class CommonUtil {  6   7      public static String setContentType(String returnFileName) {  8            String contentType = "application/octet-stream";  9             if ( returnFileName.lastIndexOf(".") < 0) 10                  return contentType; 11             returnFileName = returnFileName .toLowerCase(); 12             returnFileName = returnFileName.substring(returnFileName .lastIndexOf("." ) + 1); 13  14             if ( returnFileName.equals("html") || returnFileName.equals("htm") || returnFileName .equals("shtml" )) { 15                 contentType = "text/html"; 16            } else if ( returnFileName.equals("apk")) { 17                 contentType = "application/vnd.android.package-archive" ; 18            } else if ( returnFileName.equals("sis")) { 19                 contentType = "application/vnd.symbian.install"; 20            } else if ( returnFileName.equals("sisx")) { 21                 contentType = "application/vnd.symbian.install"; 22            } else if ( returnFileName.equals("exe")) { 23                 contentType = "application/x-msdownload"; 24            } else if ( returnFileName.equals("msi")) { 25                 contentType = "application/x-msdownload"; 26            } else if ( returnFileName.equals("css")) { 27                 contentType = "text/css"; 28            } else if ( returnFileName.equals("xml")) { 29                 contentType = "text/xml"; 30            } else if ( returnFileName.equals("gif")) { 31                 contentType = "image/gif"; 32            } else if ( returnFileName.equals("jpeg") || returnFileName.equals("jpg")) { 33                 contentType = "image/jpeg"; 34            } else if ( returnFileName.equals("js")) { 35                 contentType = "application/x-javascript"; 36            } else if ( returnFileName.equals("atom")) { 37                 contentType = "application/atom+xml"; 38            } else if ( returnFileName.equals("rss")) { 39                 contentType = "application/rss+xml"; 40            } else if ( returnFileName.equals("mml")) { 41                 contentType = "text/mathml"; 42            } else if ( returnFileName.equals("txt")) { 43                 contentType = "text/plain"; 44            } else if ( returnFileName.equals("jad")) { 45                 contentType = "text/vnd.sun.j2me.app-descriptor" ; 46            } else if ( returnFileName.equals("wml")) { 47                 contentType = "text/vnd.wap.wml"; 48            } else if ( returnFileName.equals("htc")) { 49                 contentType = "text/x-component"; 50            } else if ( returnFileName.equals("png")) { 51                 contentType = "image/png"; 52            } else if ( returnFileName.equals("tif") || returnFileName.equals("tiff")) { 53                 contentType = "image/tiff"; 54            } else if ( returnFileName.equals("wbmp")) { 55                 contentType = "image/vnd.wap.wbmp"; 56            } else if ( returnFileName.equals("ico")) { 57                 contentType = "image/x-icon"; 58            } else if ( returnFileName.equals("jng")) { 59                 contentType = "image/x-jng"; 60            } else if ( returnFileName.equals("bmp")) { 61                 contentType = "image/x-ms-bmp"; 62            } else if ( returnFileName.equals("svg")) { 63                 contentType = "image/svg+xml"; 64            } else if ( returnFileName.equals("jar") || returnFileName.equals("var") || returnFileName .equals("ear" )) { 65                 contentType = "application/java-archive"; 66            } else if ( returnFileName.equals("doc")) { 67                 contentType = "application/msword"; 68            } else if ( returnFileName.equals("pdf")) { 69                 contentType = "application/pdf"; 70            } else if ( returnFileName.equals("rtf")) { 71                 contentType = "application/rtf"; 72            } else if ( returnFileName.equals("xls")) { 73                 contentType = "application/vnd.ms-excel"; 74            } else if ( returnFileName.equals("ppt")) { 75                 contentType = "application/vnd.ms-powerpoint"; 76            } else if ( returnFileName.equals("7z")) { 77                 contentType = "application/x-7z-compressed"; 78            } else if ( returnFileName.equals("rar")) { 79                 contentType = "application/x-rar-compressed"; 80            } else if ( returnFileName.equals("swf")) { 81                 contentType = "application/x-shockwave-flash"; 82            } else if ( returnFileName.equals("rpm")) { 83                 contentType = "application/x-redhat-package-manager" ; 84            } else if ( returnFileName.equals("der") || returnFileName.equals("pem") || returnFileName .equals("crt" )) { 85                 contentType = "application/x-x509-ca-cert"; 86            } else if ( returnFileName.equals("xhtml")) { 87                 contentType = "application/xhtml+xml"; 88            } else if ( returnFileName.equals("zip")) { 89                 contentType = "application/zip"; 90            } else if ( returnFileName.equals("mid") || returnFileName.equals("midi") || returnFileName .equals("kar" )) { 91                 contentType = "audio/midi"; 92            } else if ( returnFileName.equals("mp3")) { 93                 contentType = "audio/mpeg"; 94            } else if ( returnFileName.equals("ogg")) { 95                 contentType = "audio/ogg"; 96            } else if ( returnFileName.equals("m4a")) { 97                 contentType = "audio/x-m4a"; 98            } else if ( returnFileName.equals("ra")) { 99                 contentType = "audio/x-realaudio";100            } else if ( returnFileName.equals("3gpp") || returnFileName.equals("3gp")) {101                 contentType = "video/3gpp";102            } else if ( returnFileName.equals("mp4")) {103                 contentType = "video/mp4";104            } else if ( returnFileName.equals("mpeg") || returnFileName.equals("mpg")) {105                 contentType = "video/mpeg";106            } else if ( returnFileName.equals("mov")) {107                 contentType = "video/quicktime";108            } else if ( returnFileName.equals("flv")) {109                 contentType = "video/x-flv";110            } else if ( returnFileName.equals("m4v")) {111                 contentType = "video/x-m4v";112            } else if ( returnFileName.equals("mng")) {113                 contentType = "video/x-mng";114            } else if ( returnFileName.equals("asx") || returnFileName.equals("asf")) {115                 contentType = "video/x-ms-asf";116            } else if ( returnFileName.equals("wmv")) {117                 contentType = "video/x-ms-wmv";118            } else if ( returnFileName.equals("avi")) {119                 contentType = "video/x-msvideo";120            }121 122             return contentType;123      }124 125 }

 

1 web.xml中servlet标签 2 |||||||||||||||||||| 3  4  5                
     
       6              
      
        7              
       
         ArcSyncHttpDownloadServlet
        8              
       
         ArcSyncHttpDownloadServlet
        9              
       
         com.MyHttpDownloadServlet
       10        
      
     11        
     
      12              
      
        ArcSyncHttpDownloadServlet
      13              
      
        /http
      14        
     

 

1 此类为测试类  2 |||||||||||||  3   4   5 import java.io.BufferedInputStream;  6 import java.io.File;  7 import java.io.RandomAccessFile;  8 import java.io.UnsupportedEncodingException;  9 import java.net.HttpURLConnection; 10 import java.net.URL; 11 import java.net.URLDecoder; 12  13 public class TestDownload { 14  15     /** 16      * @param args 17      */ 18     public static void main(String[] args) { 19         HttpURLConnection httpURLConnection = null; 20         URL url = null; 21         BufferedInputStream bis = null; 22         byte[] buf = new byte[10240]; 23         int size = 0; 24         String fileName = "a.exe"; 25         String filePath = "C:/Documents and Settings/Administrator/桌面"; 26         StringremoteUrl= "http://10.10.129.99:8080/project/http?filename=a.exe" ; 27          28         // 检查本地文件 29         RandomAccessFile rndFile = null; 30         File file = new File(filePath + "\\" + fileName); 31 //        long remoteFileSize = getRemoteFileSzie(remoteUrl); 32 //        long nPos = 0; 33         long localFileSzie =0; 34         if (file.exists()) {                       35            localFileSzie = file.length(); 36         } else { 37             // 建立文件 38             try { 39                 file.createNewFile(); 40             } catch (Exception e) { 41                 e.printStackTrace(); 42             }           43         } 44        45         // 下载文件 46         try { 47             url = new URL(remoteUrl);       48             httpURLConnection = (HttpURLConnection)url.openConnection(); 49             // 设置User-Agent 50             httpURLConnection.setRequestProperty( "User-Agent", "Net"); 51             // 设置续传开始 52             System. out.println( "本地文件大小：" +localFileSzie); 53             httpURLConnection.setRequestProperty( "Range", "bytes=" + localFileSzie  + "-" ); 54             // 获取输入流 55             bis = new BufferedInputStream(httpURLConnection.getInputStream());   56             57             long remoteFileSize = httpURLConnection.getContentLength(); 58             System. out.println( "返回结果码：" +httpURLConnection.getHeaderField("result")); 59             //System.out.println("文件名："+httpURLConnection.getHeaderField("Content-Disposition")); 60                  if (localFileSzie < remoteFileSize) { 61                       if (localFileSzie==0) { 62                            System. out.println( "文件不存在，开始下载..." ); 63                      } else{ 64                            System. out.println( "文件续传..." ); 65                      } 66                 } else { 67                      System. out.println( "文件存在，重新下载..." ); 68                      file.delete(); 69                       try { 70                            file.createNewFile(); 71                      } catch (Exception e) { 72                            e.printStackTrace(); 73                      } 74                 } 75             76             rndFile = new RandomAccessFile(filePath + "\\" + fileName, "rw"); 77         78             rndFile.seek(localFileSzie); 79             int i = 0; 80             while ((size = bis.read(buf)) != -1) { 81                 //if (i > 500) break;               82                 rndFile.write(buf, 0, size); 83                 i++; 84             } 85             System. out.println( "i=" + i); 86             httpURLConnection.disconnect(); 87         } catch (Exception e) { 88             e.printStackTrace(); 89         } 90     } 91  92     public static long getRemoteFileSzie(String url) { 93         long size = 0; 94         try { 95             HttpURLConnection httpUrl = (HttpURLConnection)( new URL(url)).openConnection(); 96             size = httpUrl.getContentLength(); 97             httpUrl.disconnect();           98         } catch (Exception e) { 99             e.printStackTrace();100         }101         return size;102     }103 }