java服务器端断点续传
2013-07-15 11:42
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Servlet
Java代码 复制代码 收藏代码
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.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");
}
}
Range支持
Java代码 复制代码 收藏代码
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);
}
}
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);
}
}
Range封装
Java代码 复制代码 收藏代码
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;
}
}
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;
}
}
IO流相关处理工具类
Java代码 复制代码 收藏代码
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;
}
}
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;
}
}----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
ArcSyncHttpDownloadServlet 源代码：
[java] view plaincopyprint?
01.package com.defonds.cds.common;
02.
03.import java.io.BufferedOutputStream;
04.import java.io.File;
05.import java.io.IOException;
06.import java.io.OutputStream;
07.import java.io.RandomAccessFile;
08.
09.import javax.servlet.ServletException;
10.import javax.servlet.http.HttpServlet;
11.import javax.servlet.http.HttpServletRequest;
12.import javax.servlet.http.HttpServletResponse;
13.
14.import org.apache.commons.logging.Log;
15.import org.apache.commons.logging.LogFactory;
16.
17.import com.defonds.cds.common.util.CommonUtil;
18.
19.//HTTP 断点续传 demo（客户端测试工具：快车、迅雷）
20.public class ArcSyncHttpDownloadServlet 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)
26. throws ServletException, IOException {
27. this.doPost(req, resp);
28. }
29.
30. @Override
31. protected void doPost(HttpServletRequest request, HttpServletResponse response) {
32. File downloadFile = new File("D:/defonds/book/pattern/SteveJobsZH.pdf");//要下载的文件
33. long fileLength = downloadFile.length();//记录文件大小
34. long pastLength = 0;//记录已下载文件大小
35. 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）
36. 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）
37. long contentLength = 0;//客户端请求的字节总量
38. String rangeBytes = "";//记录客户端传来的形如“bytes=27000-”或者“bytes=27000-39000”的内容
39. RandomAccessFile raf = null;//负责读取数据
40. OutputStream os = null;//写出数据
41. OutputStream out = null;//缓冲
42. byte b[] = new byte[1024];//暂存容器
43.
44. if (request.getHeader("Range") != null) {// 客户端请求的下载的文件块的开始字节
45. response.setStatus(javax.servlet.http.HttpServletResponse.SC_PARTIAL_CONTENT);
46. log.info("request.getHeader(\"Range\")=" + request.getHeader("Range"));
47. rangeBytes = request.getHeader("Range").replaceAll("bytes=", "");
48. if (rangeBytes.indexOf('-') == rangeBytes.length() - 1) {//bytes=969998336-
49. rangeSwitch = 1;
50. rangeBytes = rangeBytes.substring(0, rangeBytes.indexOf('-'));
51. pastLength = Long.parseLong(rangeBytes.trim());
52. contentLength = fileLength - pastLength + 1;//客户端请求的是 969998336 之后的字节
53. } else {//bytes=1275856879-1275877358
54. rangeSwitch = 2;
55. String temp0 = rangeBytes.substring(0,rangeBytes.indexOf('-'));
56. String temp2 = rangeBytes.substring(rangeBytes.indexOf('-') + 1, rangeBytes.length());
57. pastLength = Long.parseLong(temp0.trim());//bytes=1275856879-1275877358，从第 1275856879 个字节开始下载
58. toLength = Long.parseLong(temp2);//bytes=1275856879-1275877358，到第 1275877358 个字节结束
59. contentLength = toLength - pastLength + 1;//客户端请求的是 1275856879-1275877358 之间的字节
60. }
61. } else {//从开始进行下载
62. contentLength = fileLength;//客户端要求全文下载
63. }
64.
65. /**
66. * 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。
67. * 响应的格式是:
68. * 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]
69. * ServletActionContext.getResponse().setHeader("Content-Length",
70. * new Long(file.length() - p).toString());
71. */
72. 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
73. 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
74. if (pastLength != 0) {
75. //不是从最开始下载,
76. //响应的格式是:
77. //Content-Range: bytes [文件块的开始字节]-[文件的总大小 - 1]/[文件的总大小]
78. log.info("----------------------------不是从开始进行下载！服务器即将开始断点续传...");
79. switch (rangeSwitch) {
80. case 1 : {//针对 bytes=27000- 的请求
81. String contentRange = new StringBuffer("bytes ").append(new Long(pastLength).toString()).append("-").append(new Long(fileLength - 1).toString()).append("/").append(new Long(fileLength).toString()).toString();
82. response.setHeader("Content-Range", contentRange);
83. break;
84. }
85. case 2 : {//针对 bytes=27000-39000 的请求
86. String contentRange = rangeBytes + "/" + new Long(fileLength).toString();
87. response.setHeader("Content-Range", contentRange);
88. break;
89. }
90. default : {
91. break;
92. }
93. }
94. } else {
95. //是从开始下载
96. log.info("----------------------------是从开始进行下载！");
97. }
98.
99. try {
100. response.addHeader("Content-Disposition", "attachment; filename=\"" + downloadFile.getName() + "\"");
101. response.setContentType( CommonUtil.setContentType(downloadFile.getName()));// set the MIME type.
102. response.addHeader("Content-Length", String.valueOf(contentLength));
103. os = response.getOutputStream();
104. out = new BufferedOutputStream(os);
105. raf = new RandomAccessFile(downloadFile, "r");
106. try {
107. switch (rangeSwitch) {
108. case 0 : {//普通下载，或者从头开始的下载
109. //同1
110. }
111. case 1 : {//针对 bytes=27000- 的请求
112. raf.seek(pastLength);//形如 bytes=969998336- 的客户端请求，跳过 969998336 个字节
113. int n = 0;
114. while ((n = raf.read(b, 0, 1024)) != -1) {
115. out.write(b, 0, n);
116. }
117. break;
118. }
119. case 2 : {//针对 bytes=27000-39000 的请求
120. raf.seek(pastLength - 1);//形如 bytes=1275856879-1275877358 的客户端请求，找到第 1275856879 个字节
121. int n = 0;
122. long readLength = 0;//记录已读字节数
123. while (readLength <= contentLength - 1024) {//大部分字节在这里读取
124. n = raf.read(b, 0, 1024);
125. readLength += 1024;
126. out.write(b, 0, n);
127. }
128. if (readLength <= contentLength) {//余下的不足 1024 个字节在这里读取
129. n = raf.read(b, 0, (int)(contentLength - readLength));
130. out.write(b, 0, n);
131. }
132.//
133.// raf.seek(pastLength);//形如 bytes=1275856879-1275877358 的客户端请求，找到第 1275856879 个字节
134.// while (raf.getFilePointer() < toLength) {
135.// out.write(raf.read());
136.// }
137. break;
138. }
139. default : {
140. break;
141. }
142. }
143. out.flush();
144. } catch(IOException ie) {
145. /**
146. * 在写数据的时候，
147. * 对于 ClientAbortException 之类的异常，
148. * 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，
149. * 抛出这个异常，这个是正常的。
150. * 尤其是对于迅雷这种吸血的客户端软件，
151. * 明明已经有一个线程在读取 bytes=1275856879-1275877358，
152. * 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，
153. * 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，
154. * 强行中止字节读出，造成服务器抛 ClientAbortException。
155. * 所以，我们忽略这种异常
156. */
157. //ignore
158. }
159. } catch (Exception e) {
160. log.error(e.getMessage(), e);
161. } finally {
162. if (out != null) {
163. try {
164. out.close();
165. } catch (IOException e) {
166. log.error(e.getMessage(), e);
167. }
168. }
169. if (raf != null) {
170. try {
171. raf.close();
172. } catch (IOException e) {
173. log.error(e.getMessage(), e);
174. }
175. }
176. }
177. }
178.}
ArcSyncHttpDownloadServlet 的 web.xml 配置清单：
[html] view plaincopyprint?
01. <!-- HTTP 断点续传 demo:127.0.0.1/cds/http -->
02.<servlet>
03. <servlet-name>httpServlet</servlet-name>
04. <servlet-class>com.defonds.cds.common.ArcSyncHttpDownloadServlet</servlet-class>
05.</servlet>
06.<servlet-mapping>
07. <servlet-name>httpServlet</servlet-name>
08. <url-pattern>/http</url-pattern>
09.</servlet-mapping>
ArcSyncHttpDownloadServlet 调用到的工具类 com.defonds.cds.common.util.CommonUtil 源代码：
[java] view plaincopyprint?
01.package com.defonds.cds.common.util;
02.
03.public class CommonUtil {
04.
05. public static String setContentType(String returnFileName){
06. String contentType = "application/octet-stream";
07. if (returnFileName.lastIndexOf(".") < 0)
08. return contentType;
09. returnFileName = returnFileName.toLowerCase();
10. returnFileName = returnFileName.substring(returnFileName.lastIndexOf(".")+1);
11.
12. if (returnFileName.equals("html") || returnFileName.equals("htm") || returnFileName.equals("shtml")){
13. contentType = "text/html";
14. } else if (returnFileName.equals("css")){
15. contentType = "text/css";
16. } else if (returnFileName.equals("xml")){
17. contentType = "text/xml";
18. } else if (returnFileName.equals("gif")){
19. contentType = "image/gif";
20. } else if (returnFileName.equals("jpeg") || returnFileName.equals("jpg")){
21. contentType = "image/jpeg";
22. } else if (returnFileName.equals("js")){
23. contentType = "application/x-javascript";
24. } else if (returnFileName.equals("atom")){
25. contentType = "application/atom+xml";
26. } else if (returnFileName.equals("rss")){
27. contentType = "application/rss+xml";
28. } else if (returnFileName.equals("mml")){
29. contentType = "text/mathml";
30. } else if (returnFileName.equals("txt")){
31. contentType = "text/plain";
32. } else if (returnFileName.equals("jad")){
33. contentType = "text/vnd.sun.j2me.app-descriptor";
34. } else if (returnFileName.equals("wml")){
35. contentType = "text/vnd.wap.wml";
36. } else if (returnFileName.equals("htc")){
37. contentType = "text/x-component";
38. } else if (returnFileName.equals("png")){
39. contentType = "image/png";
40. } else if (returnFileName.equals("tif") || returnFileName.equals("tiff")){
41. contentType = "image/tiff";
42. } else if (returnFileName.equals("wbmp")){
43. contentType = "image/vnd.wap.wbmp";
44. } else if (returnFileName.equals("ico")){
45. contentType = "image/x-icon";
46. } else if (returnFileName.equals("jng")){
47. contentType = "image/x-jng";
48. } else if (returnFileName.equals("bmp")){
49. contentType = "image/x-ms-bmp";
50. } else if (returnFileName.equals("svg")){
51. contentType = "image/svg+xml";
52. } else if (returnFileName.equals("jar") || returnFileName.equals("var") || returnFileName.equals("ear")){
53. contentType = "application/java-archive";
54. } else if (returnFileName.equals("doc")){
55. contentType = "application/msword";
56. } else if (returnFileName.equals("pdf")){
57. contentType = "application/pdf";
58. } else if (returnFileName.equals("rtf")){
59. contentType = "application/rtf";
60. } else if (returnFileName.equals("xls")){
61. contentType = "application/vnd.ms-excel";
62. } else if (returnFileName.equals("ppt")){
63. contentType = "application/vnd.ms-powerpoint";
64. } else if (returnFileName.equals("7z")){
65. contentType = "application/x-7z-compressed";
66. } else if (returnFileName.equals("rar")){
67. contentType = "application/x-rar-compressed";
68. } else if (returnFileName.equals("swf")){
69. contentType = "application/x-shockwave-flash";
70. } else if (returnFileName.equals("rpm")){
71. contentType = "application/x-redhat-package-manager";
72. } else if (returnFileName.equals("der") || returnFileName.equals("pem") || returnFileName.equals("crt")){
73. contentType = "application/x-x509-ca-cert";
74. } else if (returnFileName.equals("xhtml")){
75. contentType = "application/xhtml+xml";
76. } else if (returnFileName.equals("zip")){
77. contentType = "application/zip";
78. } else if (returnFileName.equals("mid") || returnFileName.equals("midi") || returnFileName.equals("kar")){
79. contentType = "audio/midi";
80. } else if (returnFileName.equals("mp3")){
81. contentType = "audio/mpeg";
82. } else if (returnFileName.equals("ogg")){
83. contentType = "audio/ogg";
84. } else if (returnFileName.equals("m4a")){
85. contentType = "audio/x-m4a";
86. } else if (returnFileName.equals("ra")){
87. contentType = "audio/x-realaudio";
88. } else if (returnFileName.equals("3gpp") || returnFileName.equals("3gp")){
89. contentType = "video/3gpp";
90. } else if (returnFileName.equals("mp4") ){
91. contentType = "video/mp4";
92. } else if (returnFileName.equals("mpeg") || returnFileName.equals("mpg") ){
93. contentType = "video/mpeg";
94. } else if (returnFileName.equals("mov")){
95. contentType = "video/quicktime";
96. } else if (returnFileName.equals("flv")){
97. contentType = "video/x-flv";
98. } else if (returnFileName.equals("m4v")){
99. contentType = "video/x-m4v";
100. } else if (returnFileName.equals("mng")){
101. contentType = "video/x-mng";
102. } else if (returnFileName.equals("asx") || returnFileName.equals("asf")){
103. contentType = "video/x-ms-asf";
104. } else if (returnFileName.equals("wmv")){
105. contentType = "video/x-ms-wmv";
106. } else if (returnFileName.equals("avi")){
107. contentType = "video/x-msvideo";
108. }
109.
110. return contentType;
111. }
112.
113.
114.}
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