java http大文件上传，断点续传项目研究，Github上传源代码

1，项目调研

因为需要研究下断点上传的问题。找了很久终于找到一个比较好的项目。

在GoogleCode上面，代码弄下来超级不方便，还是配置hosts才好，把代码重新上传到了github上面。

https://github.com/freewebsys/java-large-file-uploader-demo

效果：

上传中，显示进度，时间，百分比。

点击【Pause】暂停，点击【Resume】继续。

2，代码分析

原始项目：

https://code.google.com/p/java-large-file-uploader/

这个项目最后更新的时间是 2012 年，项目进行了封装使用最简单的方法实现了http的断点上传。

因为html5 里面有读取文件分割文件的类库，所以才可以支持断点上传，所以这个只能在html5 支持的浏览器上面展示。

同时，在js 和 java 同时使用 cr32 进行文件块的校验，保证数据上传正确。

代码在使用了最新的servlet 3.0 的api，使用了异步执行，监听等方法。

上传类UploadServlet

@Component("javaLargeFileUploaderServlet")@WebServlet(name = "javaLargeFileUploaderServlet", urlPatterns = { "/javaLargeFileUploaderServlet" })public class UploadServlet extends HttpRequestHandlerServletimplements HttpRequestHandler {private static final Logger log = LoggerFactory.getLogger(UploadServlet.class);@AutowiredUploadProcessor uploadProcessor;@AutowiredFileUploaderHelper fileUploaderHelper;@AutowiredExceptionCodeMappingHelper exceptionCodeMappingHelper;@AutowiredAuthorizer authorizer;@AutowiredStaticStateIdentifierManager staticStateIdentifierManager;@Overridepublic void handleRequest(HttpServletRequest request, HttpServletResponse response)throws IOException {log.trace("Handling request");Serializable jsonObject = null;try {// extract the action from the requestUploadServletAction actionByParameterName =UploadServletAction.valueOf(fileUploaderHelper.getParameterValue(request, UploadServletParameter.action));// check authorizationcheckAuthorization(request, actionByParameterName);// then process the asked actionjsonObject = processAction(actionByParameterName, request);// if something has to be written to the responseif (jsonObject != null) {fileUploaderHelper.writeToResponse(jsonObject, response);}}// If exception, write itcatch (Exception e) {exceptionCodeMappingHelper.processException(e, response);}}private void checkAuthorization(HttpServletRequest request, UploadServletAction actionByParameterName)throws MissingParameterException, AuthorizationException {// check authorization// if its not get progress (because we do not really care about authorization for get// progress and it uses an array of file ids)if (!actionByParameterName.equals(UploadServletAction.getProgress)) {// extract uuidfinal String fileIdFieldValue = fileUploaderHelper.getParameterValue(request, UploadServletParameter.fileId, false);// if this is init, the identifier is the one in parameterUUID clientOrJobId;String parameter = fileUploaderHelper.getParameterValue(request, UploadServletParameter.clientId, false);if (actionByParameterName.equals(UploadServletAction.getConfig) && parameter != null) {clientOrJobId = UUID.fromString(parameter);}// if not, get it from managerelse {clientOrJobId = staticStateIdentifierManager.getIdentifier();}// call authorizerauthorizer.getAuthorization(request,actionByParameterName,clientOrJobId,fileIdFieldValue != null ? getFileIdsFromString(fileIdFieldValue).toArray(new UUID[] {}) : null);}}private Serializable processAction(UploadServletAction actionByParameterName, HttpServletRequest request)throws Exception {log.debug("Processing action " + actionByParameterName.name());Serializable returnObject = null;switch (actionByParameterName) {case getConfig:String parameterValue = fileUploaderHelper.getParameterValue(request, UploadServletParameter.clientId, false);returnObject =uploadProcessor.getConfig(parameterValue != null ? UUID.fromString(parameterValue) : null);break;case verifyCrcOfUncheckedPart:returnObject = verifyCrcOfUncheckedPart(request);break;case prepareUpload:returnObject = prepareUpload(request);break;case clearFile:uploadProcessor.clearFile(UUID.fromString(fileUploaderHelper.getParameterValue(request, UploadServletParameter.fileId)));break;case clearAll:uploadProcessor.clearAll();break;case pauseFile:List<UUID> uuids = getFileIdsFromString(fileUploaderHelper.getParameterValue(request, UploadServletParameter.fileId));uploadProcessor.pauseFile(uuids);break;case resumeFile:returnObject =uploadProcessor.resumeFile(UUID.fromString(fileUploaderHelper.getParameterValue(request, UploadServletParameter.fileId)));break;case setRate:uploadProcessor.setUploadRate(UUID.fromString(fileUploaderHelper.getParameterValue(request, UploadServletParameter.fileId)),Long.valueOf(fileUploaderHelper.getParameterValue(request, UploadServletParameter.rate)));break;case getProgress:returnObject = getProgress(request);break;}return returnObject;}List<UUID> getFileIdsFromString(String fileIds) {String[] splittedFileIds = fileIds.split(",");List<UUID> uuids = Lists.newArrayList();for (int i = 0; i < splittedFileIds.length; i++) {uuids.add(UUID.fromString(splittedFileIds[i]));} return uuids;}private Serializable getProgress(HttpServletRequest request)throws MissingParameterException {Serializable returnObject;String[] ids =new Gson().fromJson(fileUploaderHelper.getParameterValue(request, UploadServletParameter.fileId), String[].class);Collection<UUID> uuids = Collections2.transform(Arrays.asList(ids), new Function<String, UUID>() {@Overridepublic UUID apply(String input) {return UUID.fromString(input);}});returnObject = Maps.newHashMap();for (UUID fileId : uuids) {try {ProgressJson progress = uploadProcessor.getProgress(fileId);((HashMap<String, ProgressJson>) returnObject).put(fileId.toString(), progress);}catch (FileNotFoundException e) {log.debug("No progress will be retrieved for " + fileId + " because " + e.getMessage());}}return returnObject;}private Serializable prepareUpload(HttpServletRequest request)throws MissingParameterException, IOException {// extract file informationPrepareUploadJson[] fromJson =new Gson().fromJson(fileUploaderHelper.getParameterValue(request, UploadServletParameter.newFiles), PrepareUploadJson[].class);// prepare themfinal HashMap<String, UUID> prepareUpload = uploadProcessor.prepareUpload(fromJson);// return themreturn Maps.newHashMap(Maps.transformValues(prepareUpload, new Function<UUID, String>() {public String apply(UUID input) {return input.toString();};}));}private Boolean verifyCrcOfUncheckedPart(HttpServletRequest request)throws IOException, MissingParameterException, FileCorruptedException, FileStillProcessingException {UUID fileId = UUID.fromString(fileUploaderHelper.getParameterValue(request, UploadServletParameter.fileId));try {uploadProcessor.verifyCrcOfUncheckedPart(fileId,fileUploaderHelper.getParameterValue(request, UploadServletParameter.crc));}catch (InvalidCrcException e) {// no need to log this exception, a fallback behaviour is defined in the// throwing method.// but we need to return something!return Boolean.FALSE;}return Boolean.TRUE;}}

异步上传UploadServletAsync

@Component("javaLargeFileUploaderAsyncServlet")@WebServlet(name = "javaLargeFileUploaderAsyncServlet", urlPatterns = { "/javaLargeFileUploaderAsyncServlet" }, asyncSupported = true)public class UploadServletAsync extends HttpRequestHandlerServletimplements HttpRequestHandler {private static final Logger log = LoggerFactory.getLogger(UploadServletAsync.class);@AutowiredExceptionCodeMappingHelper exceptionCodeMappingHelper;@AutowiredUploadServletAsyncProcessor uploadServletAsyncProcessor;@AutowiredStaticStateIdentifierManager staticStateIdentifierManager;@AutowiredStaticStateManager<StaticStatePersistedOnFileSystemEntity> staticStateManager;@AutowiredFileUploaderHelper fileUploaderHelper;@AutowiredAuthorizer authorizer;/** * Maximum time that a streaming request can take.<br> */private long taskTimeOut = DateUtils.MILLIS_PER_HOUR;@Overridepublic void handleRequest(final HttpServletRequest request, final HttpServletResponse response)throws ServletException, IOException {// process the requesttry {//check if uploads are allowedif (!uploadServletAsyncProcessor.isEnabled()) {throw new UploadIsCurrentlyDisabled();}// extract stuff from requestfinal FileUploadConfiguration process = fileUploaderHelper.extractFileUploadConfiguration(request);log.debug("received upload request with config: "+process);// verify authorizationfinal UUID clientId = staticStateIdentifierManager.getIdentifier();authorizer.getAuthorization(request, UploadServletAction.upload, clientId, process.getFileId());//check if that file is not pausedif (uploadServletAsyncProcessor.isFilePaused(process.getFileId())) {log.debug("file "+process.getFileId()+" is paused, ignoring async request.");return;}// get the modelStaticFileState fileState = staticStateManager.getEntityIfPresent().getFileStates().get(process.getFileId());if (fileState == null) {throw new FileNotFoundException("File with id " + process.getFileId() + " not found");}// process the request asynchronouslyfinal AsyncContext asyncContext = request.startAsync();asyncContext.setTimeout(taskTimeOut);// add a listener to clear bucket and close inputstream when process is complete or// with// errorasyncContext.addListener(new UploadServletAsyncListenerAdapter(process.getFileId()) {@Overridevoid clean() {log.debug("request " + request + " completed.");// we do not need to clear the inputstream here.// and tell processor to clean its shit!uploadServletAsyncProcessor.clean(clientId, process.getFileId());}});// then processuploadServletAsyncProcessor.process(fileState, process.getFileId(), process.getCrc(), process.getInputStream(),new WriteChunkCompletionListener() {@Overridepublic void success() {asyncContext.complete();}@Overridepublic void error(Exception exception) {// handles a stream ended unexpectedly , it just means the user has// stopped the// streamif (exception.getMessage() != null) {if (exception.getMessage().equals("Stream ended unexpectedly")) {log.warn("User has stopped streaming for file " + process.getFileId());}else if (exception.getMessage().equals("User cancellation")) {log.warn("User has cancelled streaming for file id " + process.getFileId());// do nothing}else {exceptionCodeMappingHelper.processException(exception, response);}}else {exceptionCodeMappingHelper.processException(exception, response);}asyncContext.complete();}});}catch (Exception e) {exceptionCodeMappingHelper.processException(e, response);}}}

3，请求流程图：

主要思路就是将文件切分，然后分块上传。