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。基于前些日子写的《WebSocket的服务端实现》，再加上HTML 5的File API(可参考：HTML5中的文件处理 之 File API，或者W3C 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：
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<!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> |
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####### 断点续传 ######author：linrbcreateTime: 2012-08-22QQ: 569830404*/var websocket = null; //websocketvar msg = null; //日志var paragraph = 10240; //每次分片传输文件的大小 10KBvar 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('progressNumber').innerHTML = percentComplete.toString() + '%'; //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('fileToUpload').files[0]; if (file) { var fileSize = 0; if (file.size > 1024 * 1024) fileSize = (Math.round(file.size * 100 / (1024 * 1024)) / 100).toString() + 'MB'; else fileSize = (Math.round(file.size * 100 / 1024) / 100).toString() + 'KB'; document.getElementById('fileName').innerHTML = 'Name: ' + file.name; document.getElementById('fileSize').innerHTML = 'Size: ' + fileSize; document.getElementById('fileType').innerHTML = 'Type: ' + file.type; }} |
服务端：
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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(); }} |