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。
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：
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
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 | @Component ( "javaLargeFileUploaderServlet" ) @WebServlet (name = "javaLargeFileUploaderServlet" , urlPatterns = { "/javaLargeFileUploaderServlet" }) public class UploadServlet extends HttpRequestHandlerServlet implements HttpRequestHandler { private static final Logger log = LoggerFactory.getLogger(UploadServlet. class ); @Autowired UploadProcessor uploadProcessor; @Autowired FileUploaderHelper fileUploaderHelper; @Autowired ExceptionCodeMappingHelper exceptionCodeMappingHelper; @Autowired Authorizer authorizer; @Autowired StaticStateIdentifierManager staticStateIdentifierManager; @Override public void handleRequest(HttpServletRequest request, HttpServletResponse response) throws IOException { log.trace( "Handling request" ); Serializable jsonObject = null ; try { // extract the action from the request UploadServletAction actionByParameterName = UploadServletAction.valueOf(fileUploaderHelper.getParameterValue(request, UploadServletParameter.action)); // check authorization checkAuthorization(request, actionByParameterName); // then process the asked action jsonObject = processAction(actionByParameterName, request); // if something has to be written to the response if (jsonObject != null ) { fileUploaderHelper.writeToResponse(jsonObject, response); } } // If exception, write it catch (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 uuid final String fileIdFieldValue = fileUploaderHelper.getParameterValue(request, UploadServletParameter.fileId, false ); // if this is init, the identifier is the one in parameter UUID 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 manager else { clientOrJobId = staticStateIdentifierManager.getIdentifier(); } // call authorizer authorizer.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>() { @Override public 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 information PrepareUploadJson[] fromJson = new Gson() .fromJson(fileUploaderHelper.getParameterValue(request, UploadServletParameter.newFiles), PrepareUploadJson[]. class ); // prepare them final HashMap<String, UUID> prepareUpload = uploadProcessor.prepareUpload(fromJson); // return them return 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; } } |
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 | @Component ( "javaLargeFileUploaderAsyncServlet" ) @WebServlet (name = "javaLargeFileUploaderAsyncServlet" , urlPatterns = { "/javaLargeFileUploaderAsyncServlet" }, asyncSupported = true ) public class UploadServletAsync extends HttpRequestHandlerServlet implements HttpRequestHandler { private static final Logger log = LoggerFactory.getLogger(UploadServletAsync. class ); @Autowired ExceptionCodeMappingHelper exceptionCodeMappingHelper; @Autowired UploadServletAsyncProcessor uploadServletAsyncProcessor; @Autowired StaticStateIdentifierManager staticStateIdentifierManager; @Autowired StaticStateManager<StaticStatePersistedOnFileSystemEntity> staticStateManager; @Autowired FileUploaderHelper fileUploaderHelper; @Autowired Authorizer authorizer; /** * Maximum time that a streaming request can take.<br> */ private long taskTimeOut = DateUtils.MILLIS_PER_HOUR; @Override public void handleRequest( final HttpServletRequest request, final HttpServletResponse response) throws ServletException, IOException { // process the request try { //check if uploads are allowed if (!uploadServletAsyncProcessor.isEnabled()) { throw new UploadIsCurrentlyDisabled(); } // extract stuff from request final FileUploadConfiguration process = fileUploaderHelper.extractFileUploadConfiguration(request); log.debug( "received upload request with config: " +process); // verify authorization final UUID clientId = staticStateIdentifierManager.getIdentifier(); authorizer.getAuthorization(request, UploadServletAction.upload, clientId, process.getFileId()); //check if that file is not paused if (uploadServletAsyncProcessor.isFilePaused(process.getFileId())) { log.debug( "file " +process.getFileId()+ " is paused, ignoring async request." ); return ; } // get the model StaticFileState fileState = staticStateManager.getEntityIfPresent().getFileStates().get(process.getFileId()); if (fileState == null ) { throw new FileNotFoundException( "File with id " + process.getFileId() + " not found" ); } // process the request asynchronously final AsyncContext asyncContext = request.startAsync(); asyncContext.setTimeout(taskTimeOut); // add a listener to clear bucket and close inputstream when process is complete or // with // error asyncContext.addListener( new UploadServletAsyncListenerAdapter(process.getFileId()) { @Override void 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 process uploadServletAsyncProcessor.process(fileState, process.getFileId(), process.getCrc(), process.getInputStream(), new WriteChunkCompletionListener() { @Override public void success() { asyncContext.complete(); } @Override public void error(Exception exception) { // handles a stream ended unexpectedly , it just means the user has // stopped the // stream if (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。
