客户端；
import java.io.BufferedInputStream;import java.io.File;import java.io.RandomAccessFile;import java.net.HttpURLConnection;import java.net.URL;public class ArcSyncHttpClient {
public static void main(String[] args) throws Exception { String strURL = "http://localhost:8080/ArcSyncHttpDownload/httpServlet"; URL downUrl = new URL(strURL); HttpURLConnection cn = (HttpURLConnection) downUrl.openConnection(); if (cn.getResponseCode() == 200) { // InputStream is = cn.getInputStream(); int part_count = 10; int contentLength = cn.getContentLength(); System.out.println("cn.getContentLength():"+cn.getContentLength()); int firstLength = contentLength / part_count; System.out.println("firstLength():" + firstLength); cn.disconnect();// part_count = 1; for (int i = 1; i < part_count+1; i++) { if (i==part_count) { // int lastLength = contentLength -firstLength*(part_count-1); File saveFile = new File("E:/test/123",String.format("123_0%d.mp3", i)); TestDownload.download(saveFile.getName(), saveFile.getParent(), strURL, (i-1)*firstLength, contentLength); }else { File saveFile = new File("E:/test/123",String.format("123_0%d.mp3", i)); TestDownload.download(saveFile.getName(), saveFile.getParent(), strURL, (i-1)*firstLength, firstLength*i); } } } }public static void download( String fileName, String filePath,String remoteUrl, long start ,long end) {
byte[] buf = new byte[10240]; HttpURLConnection httpURLConnection; URL url; BufferedInputStream bis; int size; RandomAccessFile rndFile; // 下载文件 try { url = new URL(remoteUrl); httpURLConnection = (HttpURLConnection)url.openConnection(); // 设置User-Agent httpURLConnection.setRequestProperty("User-Agent", "Net"); // 设置续传开始 httpURLConnection.setRequestProperty("Range", "bytes=" + start + "-"+ end); // 获取输入流 bis = new BufferedInputStream(httpURLConnection.getInputStream()); rndFile = new RandomAccessFile(filePath + "\\" + fileName, "rw"); rndFile.seek(0); int i = 0; while ((size = bis.read(buf)) != -1) { //if (i > 500) break; rndFile.write(buf, 0, size); i++; } System.out.println("i=" + i); httpURLConnection.disconnect(); bis.close(); rndFile.close(); } catch (Exception e) { // TODO: handle exception e.printStackTrace(); } }public static long getRemoteFileSzie(String url) {
long size = 0; try { HttpURLConnection httpUrl = (HttpURLConnection)(new URL(url)).openConnection(); size = httpUrl.getContentLength(); httpUrl.disconnect(); } catch (Exception e) { // TODO: handle exception e.printStackTrace(); } return size; }public static void mergeFiles(String outFile, List<String> files) {
FileChannel outChannel = null; System.out.println("Merge " + files + " into " + outFile); try { outChannel = new FileOutputStream(outFile).getChannel(); for (String f : files) { FileChannel fc = new FileInputStream(f).getChannel(); ByteBuffer bb = ByteBuffer.allocate(BUFSIZE); while (fc.read(bb) != -1) { bb.flip(); outChannel.write(bb); bb.clear(); } fc.close(); } System.out.println("Merged!! "); } catch (IOException ioe) { ioe.printStackTrace(); } finally { try { if (outChannel != null) { outChannel.close(); } } catch (IOException ignore) { } } }}
服务端
package com.defonds.cds.common;
import java.io.BufferedOutputStream;import java.io.File;import java.io.IOException;import java.io.OutputStream;import java.io.RandomAccessFile;import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;//HTTP 断点续传 demo（客户端测试工具：快车、迅雷） public class ArcSyncHttpDownloadServlet extends HttpServlet { private static final long serialVersionUID = 1L; // final static Log log = LogFactory.getLog(ArcSyncHttpDownloadServlet.class); @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { this.doPost(req, resp); } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) { File downloadFile = new File("E:/test/123.mp3");//要下载的文件 long fileLength = downloadFile.length();//记录文件大小 System.out.println("fileLength："+fileLength); long pastLength = 0;//记录已下载文件大小 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） 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） long contentLength = 0;//客户端请求的字节总量 String rangeBytes = "";//记录客户端传来的形如“bytes=27000-”或者“bytes=27000-39000”的内容 RandomAccessFile raf = null;//负责读取数据 OutputStream os = null;//写出数据 OutputStream out = null;//缓冲 byte b[] = new byte[1024];//暂存容器 if (request.getHeader("Range") != null) {// 客户端请求的下载的文件块的开始字节 response.setStatus(javax.servlet.http.HttpServletResponse.SC_PARTIAL_CONTENT); System.out.println("request.getHeader(\"Range\")=" + request.getHeader("Range")); rangeBytes = request.getHeader("Range").replaceAll("bytes=", ""); int index = rangeBytes.indexOf('-'); int length = rangeBytes.length()-1; if (index == 1) {//bytes=969998336- rangeSwitch = 1; // rangeBytes = rangeBytes.substring(0, rangeBytes.indexOf('-')); String temp0 = rangeBytes.substring(0,rangeBytes.indexOf('-')); String temp2 = rangeBytes.substring(rangeBytes.indexOf('-') + 1, rangeBytes.length()); pastLength = Long.parseLong(temp0.trim()); if ("".equals(temp2)) { contentLength = fileLength - pastLength + 1;//客户端请求的是 969998336 之后的字节 }else { toLength = Long.parseLong(temp2);//bytes=1275856879-1275877358，到第 1275877358 个字节结束 contentLength = toLength - pastLength + 1;//客户端请求的是 1275856879-1275877358 之间的字节 } } else {//bytes=1275856879-1275877358 rangeSwitch = 2; String temp0 = rangeBytes.substring(0,rangeBytes.indexOf('-')); String temp2 = rangeBytes.substring(rangeBytes.indexOf('-') + 1, rangeBytes.length()); pastLength = Long.parseLong(temp0.trim());//bytes=1275856879-1275877358，从第 1275856879 个字节开始下载 toLength = Long.parseLong(temp2);//bytes=1275856879-1275877358，到第 1275877358 个字节结束 contentLength = toLength - pastLength + 1;//客户端请求的是 1275856879-1275877358 之间的字节 } } else {//从开始进行下载 contentLength = fileLength;//客户端要求全文下载 } /** * 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()); */ 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: bytes 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 OK if (pastLength != 0) { //不是从最开始下载, //响应的格式是: //Content-Range: bytes [文件块的开始字节]-[文件的总大小 - 1]/[文件的总大小] System.out.println("----------------------------不是从开始进行下载！服务器即将开始断点续传..."); switch (rangeSwitch) { case 1 : {//针对 bytes=27000- 的请求 String contentRange = new StringBuffer("bytes ").append(new Long(pastLength).toString()).append("-").append(new Long(fileLength - 1).toString()).append("/").append(new Long(fileLength).toString()).toString(); response.setHeader("Content-Range", contentRange); break; } case 2 : {//针对 bytes=27000-39000 的请求 String contentRange = rangeBytes + "/" + new Long(fileLength).toString(); response.setHeader("Content-Range", contentRange); break; } default : { break; } } } else { //是从开始下载 System.out.println("----------------------------是从开始进行下载！"); } try { response.addHeader("Content-Disposition", "attachment; filename=\"" + downloadFile.getName() + "\""); response.setContentType( CommonUtil.setContentType(downloadFile.getName()));// set the MIME type. response.addHeader("Content-Length", String.valueOf(contentLength)); os = response.getOutputStream(); out = new BufferedOutputStream(os); raf = new RandomAccessFile(downloadFile, "r"); try { switch (rangeSwitch) { case 0 : {//普通下载，或者从头开始的下载 //同1 } case 1 : {//针对 bytes=27000- 的请求 raf.seek(pastLength);//形如 bytes=969998336- 的客户端请求，跳过 969998336 个字节 int n = 0; while ((n = raf.read(b, 0, 1024)) != -1) { out.write(b, 0, n); } break; } case 2 : {//针对 bytes=27000-39000 的请求 raf.seek(pastLength - 1);//形如 bytes=1275856879-1275877358 的客户端请求，找到第 1275856879 个字节 int n = 0; long readLength = 0;//记录已读字节数 while (readLength <= contentLength - 1024) {//大部分字节在这里读取 n = raf.read(b, 0, 1024); readLength += 1024; out.write(b, 0, n); } if (readLength <= contentLength) {//余下的不足 1024 个字节在这里读取 n = raf.read(b, 0, (int)(contentLength - readLength)); out.write(b, 0, n); } // // raf.seek(pastLength);//形如 bytes=1275856879-1275877358 的客户端请求，找到第 1275856879 个字节 // while (raf.getFilePointer() < toLength) { // out.write(raf.read()); // } break; } default : { break; } } out.flush(); } catch(IOException ie) { /** * 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 */ //ignore } } catch (Exception e) { System.err.println( e); } finally { if (out != null) { try { out.close(); } catch (IOException e) { System.err.println( e); } } if (raf != null) { try { raf.close(); } catch (IOException e) { System.err.println( e); } } } } }
package com.defonds.cds.common;
public class CommonUtil {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;
}}