java http大文件断点续传上传

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

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@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;      }  }

异步上传UploadServletAsync

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@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。