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HTML5断点续上传的示例代码分享

黄舟

Mar 25, 2017 pm 04:07 PM

断点上传，java里面比较靠谱一点的，一般都会选用Flex。我承认，Flex只是摸了一下，不精通。HTML 5 有个Blob对象（File对象继承它），这个对象有个方法slice方法，可以对一个文件进行分片。，再加上HTML 5的File API和WebStorage。做了一个段断点续传的demo。

代码比较挫，把一个文件分成一个个小片之后，每一次上传都会将已经上传的字节数放到LocalStorage里面。关于LocalStorage里面缓存怎么清，可以参看Chrome - HTML 5 本地存储。如果上传的途中暂停或者直接关掉浏览器。下次上传的时候，就会从那个节点开始上传。

PS：demo操作，请先建立WS连接之后，再选择文件上传

代码请笑纳：

<!DOCTYPE html>
<html>
<head>
    <title>使用WebSocket实现断点续传文件</title>
    <meta charset="utf-8">
</head>
<script type="text/javascript" src="demo.js"></script>
 
<body onload="init();">
<button onclick="webSocketConn();">创建连接</button>(step1)
<div class="row">
      <label for="fileToUpload">Select a File to Upload</label>
      <input type="file" name="fileToUpload" id="fileToUpload" onchange="fileSelected();"/>(step2)
</div>
<div id="fileName"></div>
<div id="fileSize"></div>
<div id="fileType"></div>
<div class="row">
    <button onclick="sendFileName();uploadFile()">上传</button>(step3)
    <button onclick="pauseUpload()">暂停</button>
     <label id="progressNumber"></label>
</div>
<div id="msg" style="max-height: 400px; overflow:auto;min-height: 100px;">
</div>
</body>
</html>

#######  断点续传  ######
author：linrb
createTime: 2012-08-22
QQ: 569830404
*/
var websocket = null;  //websocket
var msg = null; //日志
var paragraph = 10240;  //每次分片传输文件的大小 10KB
var blob = null;//  分片数据的载体Blob对象
var file = null; //传输的文件
var startSize,endSize = 0; //分片的始终字节点
var uploadState = 0;  // 0: 无上传/取消， 1： 上传中， 2： 暂停
 
//初始化消息框
function init(){
    msg = document.getElementById("msg");
}
/**
 * 分片上传文件
 */
function uploadFile() {
    if(file){
        //将上传状态设置成1
        uploadState = 1;
        endSize = getLastestUploadEndSize(file);
        var reader = new FileReader();
        reader.onload = function loaded(evt) {
            var ArrayBuffer = evt.target.result;
            websocket.send(ArrayBuffer);
            uploadProgress(endSize);
        };
        if(endSize < file.size){
            //先发送文件名称
            //websocket.send(file.name);
            //处理文件发送（字节）
            startSize = endSize;
            if(paragraph > (file.size - endSize)){
                endSize = file.size;
            }else{
                endSize += paragraph ;
            }
            if (file.webkitSlice) {
              //webkit浏览器
                blob = file.webkitSlice(startSize, endSize);
            }else
                blob = file.slice(startSize, endSize);
            reader.readAsArrayBuffer(blob);
        }
    }
}
 
//显示处理进程
function uploadProgress(uploadLen) {
    var percentComplete = Math.round(uploadLen * 100 / file.size);
    document.getElementById(&#39;progressNumber&#39;).innerHTML = percentComplete.toString() + &#39;%&#39;;
 
    //保存到LocalStorage一边下次传输，可以记忆起这个断点
    localStorage.setItem(file.lastModifiedDate + "_" + file.name, uploadLen);
     
}
 
//WebSocket连接
function webSocketConn(){
    try{
        var readyState = new Array("正在连接", "已建立连接", "正在关闭连接"
                    , "已关闭连接");
        var host = "ws://localhost:8000";
        websocket = new WebSocket(host);
        websocket.onopen = function(){
            msg.innerHTML += "<p>Socket状态： " + readyState[websocket.readyState] + "</p>";
        };
        websocket.onmessage = function(event){
            //每上传一个分片之后，等待介绍了服务端的提示之后再做下一个分片上传
            if(event.data.indexOf("ok") != -1 && uploadState == 1){
                if(endSize == file.size){
                    localStorage.removeItem(file.lastModifiedDate + "_" + file.name);
                    msg.innerHTML += "<p>上传完成!!</p>";
                    websocket.close();//结束上传
                }else{
                    uploadFile();
                }
            }
        };
        websocket.onclose = function(){
            msg.innerHTML += "<p>Socket状态： " + readyState[websocket.readyState] + "</p>";
        };
        msg.innerHTML += "<p>Socket状态： " + readyState[websocket.readyState] + "</p>";
    }catch(exception){
        msg.innerHTML += "<p>有错误发生</p>";
        return;
    }
}
 
/*
暂停上传
*/
function pauseUpload(){
    uploadState = 2;
}
 
/**
 * 从localStorage检查最后一次上传的字节
 */
function getLastestUploadEndSize(uploadFile){
    var lastestLen = localStorage.getItem(uploadFile.lastModifiedDate + "_" + uploadFile.name);
    if(lastestLen){
        return parseInt(lastestLen);
    }else{
        return 0;
    }
}
 
 
/*
    发送文件名
*/
function sendFileName(){
    websocket.send(file.name);
}
/**
 * 选择文件之后触发事件
 */
function fileSelected() {
  file = document.getElementById(&#39;fileToUpload&#39;).files[0];
  if (file) {
    var fileSize = 0;
    if (file.size > 1024 * 1024)
      fileSize = (Math.round(file.size * 100 / (1024 * 1024)) / 100).toString() + &#39;MB&#39;;
    else
      fileSize = (Math.round(file.size * 100 / 1024) / 100).toString() + &#39;KB&#39;;
 
    document.getElementById(&#39;fileName&#39;).innerHTML = &#39;Name: &#39; + file.name;
    document.getElementById(&#39;fileSize&#39;).innerHTML = &#39;Size: &#39; + fileSize;
    document.getElementById(&#39;fileType&#39;).innerHTML = &#39;Type: &#39; + file.type;
  }
}

服务端：

package fileUpload;
 
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.nio.ByteBuffer;
import java.nio.charset.Charset;
import java.security.MessageDigest;
 
 
 
public class UploadServer {
    private int port = 8000;
    private ServerSocket serverSocket;
 
    public UploadServer() throws IOException {
        serverSocket = new ServerSocket(port);
        System.out.println("服务器启动");
    }
 
    private void service() {
        Socket socket = null;
        while (true) {
            try {
                socket = serverSocket.accept();
                Thread workThread = new Thread(new Handler(socket));
                workThread.start();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
 
    class Handler implements Runnable {
        private Socket socket;
        private boolean hasHandshake = false;
        Charset charset = Charset.forName("UTF-8");  
        private File file = null;
        private FileOutputStream fileOut = null;
         
        public Handler(Socket socket) {
            this.socket = socket;
        }
 
        private PrintWriter getWriter(Socket socket) throws IOException {
            OutputStream socketOut = socket.getOutputStream();
            return new PrintWriter(socketOut, true);
        }
 
 
        public String echo(String msg) {
            return "echo:" + msg;
        }
 
        public void run() {
             
            try {
                System.out.println("New connection accepted"
                        + socket.getInetAddress() + ":" + socket.getPort());
                InputStream in = socket.getInputStream();
                 
                PrintWriter pw = getWriter(socket);
                //读入缓存
                byte[] buf = new byte[1024];
                //读到字节
                int len = in.read(buf, 0, 1024);
                //读到字节数组
                byte[] res = new byte[len];
                System.arraycopy(buf, 0, res, 0, len);
                String key = new String(res);
                if(!hasHandshake && key.indexOf("Key") > 0){
                    key = key.substring(0, key.indexOf("==") + 2);
                    key = key.substring(key.indexOf("Key") + 4, key.length()).trim();
                    key+= "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
                    MessageDigest md = MessageDigest.getInstance("SHA-1");  
                    md.update(key.getBytes("utf-8"), 0, key.length());
                    byte[] sha1Hash = md.digest();  
                        sun.misc.BASE64Encoder encoder = new sun.misc.BASE64Encoder();  
                    key = encoder.encode(sha1Hash);  
                    pw.println("HTTP/1.1 101 Switching Protocols");
                    pw.println("Upgrade: websocket");
                    pw.println("Connection: Upgrade");
                    pw.println("Sec-WebSocket-Accept: " + key);
                    pw.println();
                    pw.flush();
                    hasHandshake = true;
                     
                    //接收数据
                    byte[] first = new byte[1];
                        int read = in.read(first, 0, 1);
                        while(read > 0){
                            int b = first[0] & 0xFF;
                            //boolean fin = (b & 0x80) > 0;
                           // int rsv = (b & 0x70) >>> 4;
                            byte opCode = (byte) (b & 0x0F);
                             
                            if(opCode == 8){
                            socket.getOutputStream().close();
                            file = null;
                            fileOut.flush();
                            fileOut.close();
                            fileOut = null;
                            break;
                            }
                            b = in.read();
                            int payloadLength = b & 0x7F;
                            if (payloadLength == 126) {
                                byte[] extended = new byte[2];
                                in.read(extended, 0, 2);
                                int shift = 0;
                                payloadLength = 0;
                            for (int i = extended.length - 1; i >= 0; i--) {
                                payloadLength = payloadLength + ((extended[i] & 0xFF) << shift);
                                shift += 8;
                            }
 
                        } else if (payloadLength == 127) {
                            byte[] extended = new byte[8];
                            in.read(extended, 0, 8);
                            int shift = 0;
                            payloadLength = 0;
                            for (int i = extended.length - 1; i >= 0; i--) {
                                payloadLength = payloadLength + ((extended[i] & 0xFF) << shift);
                                shift += 8;
                            }
                        }
                         
                        //掩码
                        byte[] mask = new byte[4];
                        in.read(mask, 0, 4);
                        int readThisFragment = 1;
                        ByteBuffer byteBuf = ByteBuffer.allocate(payloadLength);
                        while(payloadLength > 0){
                             int masked = in.read();
                             masked = masked ^ (mask[(int) ((readThisFragment - 1) % 4)] & 0xFF);
                             byteBuf.put((byte) masked);
                             payloadLength--;
                             readThisFragment++;
                        }
                        byteBuf.flip();
                        if(opCode == 1){
                            getChar(byteBuf.array());
                        }else
                            outFile(byteBuf.array());
                        in.read(first, 0, 1);
                    }
                     
                }
                in.close();
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                try {
                    if (socket != null)
                        socket.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
         
        private void responseClient(boolean finalFragment) throws IOException {
            ByteBuffer byteBuf = ByteBuffer.allocate(10);
            byteBuf.put("ok".getBytes("UTF-8"));
            OutputStream out = socket.getOutputStream();
            int first = 0x00;
            //是否是输出最后的WebSocket响应片段，默认
            if (finalFragment) {
                first = first + 0x80;
                first = first + 0x1;
            }
            out.write(first);
             
 
            if (byteBuf.limit() < 126) {
                out.write(byteBuf.limit());
            } else if (byteBuf.limit() < 65536) {
                out.write(126);
                out.write(byteBuf.limit() >>> 8);
                out.write(byteBuf.limit() & 0xFF);
            } else {
                // Will never be more than 2^31-1
                out.write(127);
                out.write(0);
                out.write(0);
                out.write(0);
                out.write(0);
                out.write(byteBuf.limit() >>> 24);
                out.write(byteBuf.limit() >>> 16);
                out.write(byteBuf.limit() >>> 8);
                out.write(byteBuf.limit() & 0xFF);
 
            }
 
            // Write the content
            out.write(byteBuf.array(), 0, byteBuf.limit());
            out.flush();
        }
         
        /**
         * 方法说明:
         * @开发：linrb
         * @创建时间：2012-8-21
         * @param array
         * @throws IOException 
         */
        private void getChar(byte[] array) throws IOException {
            ByteArrayInputStream  byteIn = new ByteArrayInputStream(array);
            InputStreamReader reader = new InputStreamReader(byteIn, charset.newDecoder());
            int b = 0;
            String res = "";
            try {
                while((b = reader.read()) > 0){
                    res += (char)b;
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
            file = new File("C:/" + res);
        }
 
        /**
         * 方法说明:
         * @开发：linrb
         * @创建时间：2012-8-14
         * @param array
         * @throws IOException 
         */
        private void outFile(byte[] array) throws IOException {
            if(fileOut == null){
                fileOut = new FileOutputStream(file, true);
            }
            fileOut.write(array);
            responseClient(true);
        }
    }
 
    public static void main(String[] args) throws IOException {
        new UploadServer().service();
    }
}

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