断点续传指的是在下载或上传时，将下载或上传任务（一个文件或一个压缩包）人为的划分为几个部分，每一个部分采用一个片段进行上传或下载，如果碰到网络故障，可以从已经上传或下载的部分开始继续上传下载未完成的部分，而没有必要从头开始上传下载。用户可以节省时间，提高速度。
本文采用WebUploader插件实现对大文件进行唯一标识，并分块进行上传。
1、CheckChumServlet 进行文件唯一标识的判断，是否已经上传过；
2、UploadVideoServlet 文件的分块上传；
3、UploadSuccessServlet 对分块的文件进行合并。
index.jsp
<%@ page language="java" contentType="text/html;charset=UTF-8" pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>视频文件上传</title>
<base
href="${pageContext.request.scheme}://${pageContext.request.serverName}:${pageContext.request.serverPort}${pageContext.request.contextPath}/">
<script type="text/javascript" src="webuploader/jquery-1.7.2.js"></script>
<script type="text/javascript" src="webuploader/webuploader.min.js"></script>
<link href="webuploader/webuploader.css" type="css/text" />
</head>
<body>
<h2 >视频文件上传</h2>
<div style="margin: 20px 20px 20px 0;">
<div id="picker" class="form-control-focus" >选择文件</div>
</div>
<div id="thelist" class="uploader-list"></div>
<button id="btnSync" type="button" class="btn btn-warning">开始上传</button>
<div class="progress">
<div id="progress" class="progress-bar" role="progressbar" aria-valuenow="60" aria-valuemin="0" aria-valuemax="100" style="width: 0%;">
<span class="sr-only"></span>
</div>
</div>
<script>
_extensions ='3gp,mp4,rmvb,mov,avi,m4v,qlv,wmv';
_mimeTypes ='video/*,audio/*,application/*';
var fileMd5; //文件唯一标识
/******************下面的参数是自定义的*************************/
var fileId;//文件ID
var fileName;//文件名称
var oldJindu;//如果该文件之前上传过 已经上传的进度是多少
var count=0;//当前正在上传的文件在数组中的下标，一次上传多个文件时使用
var filesArr=new Array();//文件数组：每当有文件被添加进队列的时候 就push到数组中
var map={};//key存储文件id，value存储该文件上传过的进度
//监听分块上传的三种状态
WebUploader.Uploader.register({
"before-send-file":"beforeSendFile",//整个文件上传前
"before-send":"beforeSend", //每个分片上传前
"after-send-file":"afterSendFile", //分片上传完毕
},
{
//所有分块进行上传之前调用此函数
beforeSendFile:function(file){
//alert('分块上传前调用的函数');
var deferred = WebUploader.Deferred();
//1、计算文件的唯一标记fileMd5，用于断点续传 如果.md5File(file)方法里只写一个file参数则计算MD5值会很慢 所以加了后面的参数：5*1024*1024
(new WebUploader.Uploader()).md5File(file,0,5*1024*1024).progress(function(percentage){
$('#'+file.id ).find('p.state').text('正在读取文件信息...');
})
.then(function(val){
$('#'+file.id ).find("p.state").text("正在上传...");
fileMd5=val;
fileId=file.id;
uploader.options.formData.guid = fileMd5;
//获取文件信息后进入下一步
deferred.resolve();
});
fileName=file.name; //为自定义参数文件名赋值
return deferred.promise();
},
//如果有分块上传，则每个分块上传之前调用此函数 ，检验该分片是否上传过
beforeSend:function(block){
//alert('-检验分块是否上传-');
var deferred = WebUploader.Deferred();
$.ajax({
type:"POST",
url:"CheckChumServlet", //ajax验证每一个分片
data:{
fileName : fileName,
fileMd5:fileMd5, //文件唯一标记
chunk:block.chunk, //当前分块下标
chunkSize:block.end-block.start,//当前分块大小
guid: uploader.options.formData.guid
},
cache: false,
async: false, // 与js同步
timeout: 1000, //todo 超时的话，只能认为该分片未上传过
dataType:"json",
success:function(response){
if(response.ifExist){
$('#'+fileId).find("p.state").text("正在续传...");
//分块存在，跳过
deferred.reject();
}else{
//alert("分块文件不完整或没有上传，重新上传")
//分块不存在或不完整，重新发送该分块内容
deferred.resolve();
}
}
});
this.owner.options.formData.fileMd5 = fileMd5;
deferred.resolve();
//继续执行分片上传
return deferred.promise();
},
//所有分块上传成功后调用此函数，通知后台合并所用分块
afterSendFile:function(){
//alert('-所有分块上传完成后调用该函数-');
//如果分块上传成功，则通知后台合并分块
$.ajax({
type:"POST",
url:"UploadSuccessServlet", //ajax将所有片段合并成整体
data:{
fileName : fileName,
fileMd5:fileMd5,
},
success:function(){
count++; //每上传完成一个文件 count+1
if(count<=filesArr.length-1){
uploader.upload(filesArr[count].id);//上传文件列表中的下一个文件
}
//合并成功之后的操作
}
});
}
});
var uploader = WebUploader.create({
// swf文件路径
swf : 'webuploader/Uploader.swf',
// 文件接收服务端。
server : 'UploadVideoServlet',
// 选择文件的按钮。可选。
// 内部根据当前运行是创建，可能是input元素，也可能是flash.
pick : {
id:'#picker',
multiple: false
},
accept: {
title: 'Videos',
extensions: _extensions,
mimeTypes: _mimeTypes
},
chunked: true, //分片处理
chunkSize: 5 * 1024 * 1024, //每片5M
threads:1,//上传并发数。允许同时最大上传进程数。
// 不压缩image, 默认如果是jpeg，文件上传前会压缩一把再上传！
resize : false
});
uploader.on("error", function (type) {
if (type == "Q_TYPE_DENIED") {
alert("请上传mp4、rmvb、mov、avi、m4v、wmv格式文件");
}
});
// 当有文件被添加进队列的时候
uploader.on('fileQueued', function(file) {
//alert(123);
$("#thelist").append(
'<div id="' + file.id + '" class="item">'
+ '<h4 class="info">' + file.name + '</h4>'
+ '<p class="file-pro"></p>'
+ '<p class="state">等待上传...</p>' + '</div>');
});
uploader.on('uploadSuccess', function(file) {
$('#' + file.id).find('p.state').text('已上传');
});
uploader.on('uploadError', function(file) {
$('#' + file.id).find('p.state').text('上传出错');
});
uploader.on('uploadComplete', function(file) {
$('#' + file.id).find('.progress').fadeOut();
});
uploader.on( 'beforeFileQueued', function( file ) {
// alert(file.size);
});
$("#btnSync").on('click', function() {
if ($(this).hasClass('disabled')) {
return false;
}
//显示遮罩层操作
//视频上传
uploader.upload();
});
// 文件上传过程中创建进度条实时显示
uploader.on( 'uploadProgress', function( file, percentage ) {
$("td.file-pro").text("");
var $li = $( '#'+file.id ).find('.file-pro'),
$percent = $li.find('.file-progress .progress-bar');
// 避免重复创建
if ( !$percent.length ) {
$percent = $('<div class="file-progress progress-striped active">' +
'<div class="progress-bar" role="progressbar" style="width: 0%">' +
'</div>' +
'</div>' + '<br/><div class="per">0%</div>').appendTo( $li ).find('.progress-bar');
}
$li.siblings('.file-status').text('上传中');
$li.find('.per').text((percentage * 100).toFixed(2) + '%');
$percent.css( 'width', percentage * 100 + '%' );
});
// 所有文件上传成功后调用
uploader.on('uploadFinished', function () {
//隐藏遮罩层操作
});
/*关闭上传框窗口后恢复上传框初始状态*/
$('#picker').on('click',function(){
// 移除所有并将上传文件移出上传序列
for (var i = 0; i < uploader.getFiles().length; i++) {
// 将文件从上传序列移除
uploader.removeFile(uploader.getFiles()[i]);
$("#"+uploader.getFiles()[i].id).remove();
}
// 重置uploader
uploader.reset();
})
</script>
</body>
</html>
CheckChumServlet
package com.uploader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.commons.io.FileUtils;
/**
* 分片上传文件处理类
*/
public class CheckChumServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public CheckChumServlet() {
super();
}
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.getWriter().append("Served at: ").append(request.getContextPath());
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// 获取分块传文件的相关信息
String chunk = request.getParameter("chunk");
String chunkSize = request.getParameter("chunkSize");
String guid = request.getParameter("guid");
//String fileName = request.getParameter("fileName");
//String fileMd5 = request.getParameter("fileMd5");
// 获取分块文件临时存储的路径并新建该分块文件
String path = request.getSession().getServletContext().getRealPath("/upload");
File checkFile = new File(path + "/" + guid + "/" + chunk);
// 设置响应编码为utf-8
response.setContentType("text/html;charset=utf-8");
// 检查文件是否存在，且大小是否一致
if (checkFile.exists() && checkFile.length() == Integer.parseInt(chunkSize)) {
// 上传过 将结果返回给前段处理
try {
response.getWriter().write("{\"ifExist\":1}");
// System.out.println("分块文件已经存在");
} catch (IOException e) {
e.printStackTrace();
}
} else {
// 没有上传过 返回给前段做处理
try {
response.getWriter().write("{\"ifExist\":0}");
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
UploadVideoServlet
package com.uploader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.commons.io.FileUtils;
/**
* 接受上传文件的servlet
*/
public class UploadVideoServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* 该类的无参构造方法
*/
public UploadVideoServlet() {
super();
}
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.getWriter().append("Served at: ").append(request.getContextPath());
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// 临时文件的保存路
String path = request.getSession().getServletContext().getRealPath("/upload");
// System.out.println(path);
DiskFileItemFactory factory = new DiskFileItemFactory();
// 2、创建一个文件上传解析器
ServletFileUpload upload = new ServletFileUpload(factory);
// 设置单个文件的最大上传
upload.setFileSizeMax(15 * 1024 * 1024L);
// 设置整个request的最大内存
upload.setSizeMax(15 * 1024 * 1024L);
// 解决上传文件名的中文乱码
upload.setHeaderEncoding("UTF-8");
// 3、判断提交上来的数据是否是上传表单的数据
if (!ServletFileUpload.isMultipartContent(request)) {
return;
}
// 4、使用ServletFileUpload解析器解析上传数据，解析结果返回的是一个List<FileItem>集合，每一个FileItem对应一个Form表单的输入项
List<FileItem> list = null;
try {
list = upload.parseRequest(request);
} catch (FileUploadException e) {
e.printStackTrace();
}
HashMap<String, String> map = new HashMap<String, String>();
for (FileItem item : list) {
if (item.isFormField()) {
String name = item.getFieldName();
// 解决输入项的数据的中文乱码问题
String value = item.getString("UTF-8");
map.put(name, value);// 放入map集合
} else {
File fileParent = new File(path + "/" + map.get("guid"));// 以guid创建临时文件夹
if (!fileParent.exists()) {
fileParent.mkdirs();
}
String filename = item.getName();
if (filename == null || filename.trim().equals("")) {
continue;
}
// 处理获取到的上传文件的文件名的路径部分，只保留文件名部分
filename = filename.substring(filename.lastIndexOf("\\") + 1);
// 创建文件
File file;
// 以chunks分块文件的下标作为上传文件的名字
if (map.get("chunks") != null) {
file = new File(fileParent, map.get("chunk"));
} else {
file = new File(fileParent, "0");
}
// 将分块文件写入到该文件中
InputStream in = null;
FileOutputStream out = null;
byte[] byt = new byte[5 * 1024 * 1024];
try {
in = item.getInputStream();
out = new FileOutputStream(file);
int len;
while ((len = in.read(byt)) != -1) {
out.write(byt, 0, len);
}
} catch (Exception e) {
throw new RuntimeException("写入失败");
} finally {
try {
in.close();
} catch (Exception e2) {
throw new RuntimeException("关闭流失败");
}
try {
out.close();
} catch (Exception e2) {
throw new RuntimeException("关闭流失败");
}
}
}
}
}
}
UploadSuccessServlet
package com.uploader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
//文件合并类
public class UploadSuccessServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* 该类的无参构造方法
*/
public UploadSuccessServlet() {
super();
}
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.getWriter().append("Served at: ").append(request.getContextPath());
}
/**
* 上传成功后的业务处理
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// 获取上传路径
String path = request.getSession().getServletContext().getRealPath("/upload");
// 获取guid参数
String guid = request.getParameter("fileMd5");
// 获取文件名字
String fileName = request.getParameter("fileName");
// System.out.println("开始合并。。。文件唯一表示符="+guid+";文件名字="+fileName);
// 创建保存文件的文件夹
new File("D:/XALC/DP/LianYunGangDaShuJuDP20181031-1/App_Uploads" + "/" + guid).mkdirs();
// 进行文件合并
File newFile = new File("D:/XALC/DP/LianYunGangDaShuJuDP20181031-1/App_Uploads" + "/" + guid + "/" + fileName);
FileInputStream temp = null;
FileOutputStream outputStream = null;
List<File> files = null;
File dir = null;
dir = new File(path + "/" + guid);
File[] childs = dir.listFiles();
files = Arrays.asList(childs);
Collections.sort(files, new Comparator<File>() {
@Override
public int compare(File o1, File o2) {
int o1Num = Integer.parseInt(o1.getName());
int o2Num = Integer.parseInt(o2.getName());
return o1Num - o2Num;
}
});
try {
int len;
byte[] byt = new byte[5 * 1024 * 1024];
outputStream = new FileOutputStream(newFile, true);// 文件追加写入
for (int i = 0; i < files.size(); i++) {
temp = new FileInputStream(files.get(i));
while ((len = temp.read(byt)) != -1) {
outputStream.write(byt, 0, len);
}
temp.close();
temp = null;
}
} catch (IOException e) {
throw new RuntimeException("合并文件失败");
} finally {
if (temp != null) {
temp.close();
}
outputStream.close();
}
for (int i = 0; i < files.size(); i++) {
//删除临时文件
files.get(i).delete();
}
//删除临时文件夹
dir.delete();
}
}
web.xml中注册servlet:
<servlet>
<description></description>
<display-name>UploadVideoServlet</display-name>
<servlet-name>UploadVideoServlet</servlet-name>
<servlet-class>com.uploader.UploadVideoServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>UploadVideoServlet</servlet-name>
<url-pattern>/UploadVideoServlet</url-pattern>
</servlet-mapping>
<servlet>
<description></description>
<display-name>UploadSuccessServlet</display-name>
<servlet-name>UploadSuccessServlet</servlet-name>
<servlet-class>com.uploader.UploadSuccessServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>UploadSuccessServlet</servlet-name>
<url-pattern>/UploadSuccessServlet</url-pattern>
</servlet-mapping>
<servlet>
<description></description>
<display-name>CheckChumServlet</display-name>
<servlet-name>CheckChumServlet</servlet-name>
<servlet-class>com.uploader.CheckChumServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>CheckChumServlet</servlet-name>
<url-pattern>/CheckChumServlet</url-pattern>
</servlet-mapping>WebUploader前端资源以及lib下载