我想检查上传文件的大小并防止文件完全加载到内存中。我正在使用CommonsMultipartFile。上传的文件将被处理并保存在DB中。 AbstractCoupleUploadController类处理包含文件的传入请求：
public abstract class AbstractCoupleUploadController<T extends Serializable> extends RemoteServiceServlet implements ServletContextAware,
UploadServlet<WorkshopHistoryModel>
{
...
@RequestMapping(method={RequestMethod.GET,RequestMethod.POST})
public ModelAndView handleRequest(@RequestParam("firstFile") CommonsMultipartFile firstFile,
@RequestParam("secondFile") CommonsMultipartFile secondFile, HttpServletRequest request, HttpServletResponse response)
{
synchronized(this)
{
initThreads();
perThreadRequest.set(request);
perThreadResponse.set(response);
}
handleUpload(firstFile,secondFile,request,response);
response.getWriter().flush();
response.flushBuffer();
return null;
}
private void handleUpload(CommonsMultipartFile firstFile, CommonsMultipartFile secondFile, HttpServletRequest request,
HttpServletResponse response) throws IOException
{
response.setContentType("text/html");
if(firstFile.getSize() == 0 || secondFile.getSize() == 0)
{
response.getWriter().print(AppConstants.UPLOAD_ZERO_SIZE_FILE);
return;
}
// other validations
// uploading:
try
{
String content = request.getParameter(CoupleUploadPanel.CONTENT);
T model = deserialize(content);
UploadResultModel resultModel = upload(model,firstFile,secondFile); // it's implemented in UploadFileServletImpl
if(resultModel.hasCriticalError())
{
response.getWriter().print(AppConstants.UPLOAD_FAIL + "," + String.valueOf(resultModel.getWorkshopHistoryId()));
}
else
{
response.getWriter().print(AppConstants.UPLOAD_SUCCESS + "," + String.valueOf(resultModel.getWorkshopHistoryId()));
}
}
catch(ProcessRequestException e)
{
// write upload error description in response.getWriter()
}
catch(Exception e)
{
e.printStackTrace();
response.getWriter().print(AppConstants.UPLOAD_UNKOWN_ERROR);
}
}
...
}
我的app-servlet.xml中有一个multipartResolver bean（file.upload.max_size = 9437184），还有一个用于处理UploadSizeExceededExceptions的maxUploadSizeExceededExceptionHandler bean：
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
<property name="maxUploadSize" value="${file.upload.max_size}" />
</bean>
<bean id="maxUploadSizeExceededExceptionHandler" class="com.insurance.ui.server.uploadfile.MaxUploadSizeExceededExceptionHandler">
<property name="order" value="1"/>
</bean>
我的maxUploadSizeExceededExceptionHandler：
public class MaxUploadSizeExceededExceptionHandler implements HandlerExceptionResolver, Ordered
{
private int order;
@Override
public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
{
if(ex instanceof MaxUploadSizeExceededException)
{
try
{
response.getWriter().print(ErrorConstants.UPLOAD_SIZE_EXCEED + "," + (((MaxUploadSizeExceededException) ex).getMaxUploadSize()/(1024*1024)));
response.getWriter().flush();
response.flushBuffer();
return new ModelAndView();
}
catch(IOException e)
{
}
}
return null;
}
...
}
当我上传一个非常大的文件（超过$ {file.upload.max_size}，大约700MB）时，CommonsMultipartResolver会立即抛出MaxUploadSizeExceededException，我正在捕捉并处理它（写在response.getWriter（）中）.But < strong>我的问题：我的浏览器上传进度条显示文件仍在上传!!为什么？
更新：我正在使用：
并尝试过：
和我的AS：
更新2：在客户端，我正在使用GWT（我认为没关系）：
点击submitRequestButton：
开始上传@UiHandler("submitRequestButton")
public void submitRequestButtonClick(ClickEvent event)
{
try
{
// some validation
submitRequestButton.setEnabled(false);
uploadPanel.upload(model.getWorkshopHistoryModel()); // uploadPanel is from the CoupleUploadPanel type
}
catch(ValidationException exception)
{
// handle validation errors
}
catch(SerializationException e)
{
// handle serialization errors
}
}
我有一个用于上传的CoupleUploadPanel小部件（两个文件）：
public class CoupleUploadPanel<T extends Serializable> extends FormPanel
{
public final static String CONTENT = "content";
private static final String FIRST_FILE = "firstFile";
private static final String SECOND_FILE = "secondFile";
private Hidden contentInput;
private FileUpload firstFileUploadInput;
private FileUpload secondFileUploadInput;
private SerializationStreamFactory factory;
public CoupleUploadPanel(UploadServletAsync<T> factory)
{
this(null,factory);
}
public CoupleUploadPanel(String url, UploadServletAsync<T> factory)
{
this.factory = (SerializationStreamFactory) factory;
if(url != null)
{
setAction(url);
}
init();
}
public CoupleUploadPanel(String target, String url, UploadServletAsync<T> factory)
{
super(target);
this.factory = (SerializationStreamFactory) factory;
if(url != null)
{
setAction(url);
}
init();
}
private void init()
{
setMethod("POST");
setEncoding(ENCODING_MULTIPART);
firstFileUploadInput = new FileUpload();
firstFileUploadInput.setName(CoupleUploadPanel.FIRST_FILE);
secondFileUploadInput = new FileUpload();
secondFileUploadInput.setName(CoupleUploadPanel.SECOND_FILE);
contentInput = new Hidden();
contentInput.setName(CONTENT);
VerticalPanel panel = new VerticalPanel();
panel.add(firstFileUploadInput);
panel.add(secondFileUploadInput);
panel.add(contentInput);
add(panel);
}
public void upload(T input) throws SerializationException
{
contentInput.setValue(serialize(input));
submit();
}
private String serialize(T input) throws SerializationException
{
SerializationStreamWriter writer = factory.createStreamWriter();
writer.writeObject(input);
return writer.toString();
}
}
我们应该将UploadServletAsync传递给CoupleUploadPanel构造函数。 UploadServletAsync和UploadServlet接口：
public interface UploadServletAsync<T extends Serializable>
{
void upload(T model, AsyncCallback<Void> callback);
}
public interface UploadServlet<T extends Serializable> extends RemoteService
{
void upload(T model);
}
所以 uploadPanel 将以这种方式实例化：
uploadPanel= new CoupleUploadPanel<WorkshopHistoryModel>((UploadFileServletAsync) GWT.create(UploadFileServlet.class));
uploadPanel.setAction(UploadFileServlet.URL);
添加到uploadPanel的SubmitCompeleteHandler（ onSumbitComplete（）将在提交完成并且结果传递到客户端时被调用）：
uploadPanel.addSubmitCompleteHandler(new SubmitCompleteHandler()
{
@Override
public void onSubmitComplete(SubmitCompleteEvent event)
{
String s = event.getResults(); //contains whatever written by response.getWriter()
if(s == null)
{
// navigate to request list page
}
else
{
String[] response = s.split(",");
// based on response:
// show error messages if any error occurred in file upload
// else: navigate to upload result page
}
}
});
UploadFileServlet和UploadFileServletAsync接口：
public interface UploadFileServlet extends UploadServlet<WorkshopHistoryModel>
{
String URL = "**/uploadFileService.mvc";
}
public interface UploadFileServletAsync extends UploadServletAsync<WorkshopHistoryModel>
{
public static final UploadFileServletAsync INSTANCE = GWT.create(UploadFileServlet.class);
}
在服务器端：UploadFileServletImpl扩展了AbstractCoupleUploadController并实现了 upload（）方法（上传过程）：
@RequestMapping(UploadFileServlet.URL)
public class UploadFileServletImpl extends AbstractCoupleUploadController<WorkshopHistoryModel>
{
...
@Override
protected UploadResultModel upload(WorkshopHistoryModel model, MultipartFile firstFile, MultipartFile secondFile)
throws ProcessRequestException
{
return workshopHistoryService.submitList(model.getWorkshop(),firstFile,secondFile);
}
...
}
答案 0 :(得分：1)
好吧，afaik Spring（一个servlet和一些过滤器）没有观察到上传过程，只是处理完成过程的结果。那是因为上传是由Tomcat自己处理的（提示：web.xml中有一个上传大小限制选项）。因此，可能会导致上载失败（Spring不会被注意到）或上传过大的文件。只有当第二次发生时，特定的过滤器/拦截器才能拒绝该过程。
在我的上一次设置中，我在Tomcat前面使用Nginx作为代理：
答案 1 :(得分：0)
我们使用以下方法：
public class MultipartResolver extends CommonsMultipartResolver {
public MultipartHttpServletRequest resolveMultipart(HttpServletRequest request) throws MultipartException {
String encoding = determineEncoding(request);
FileUpload fileUpload = prepareFileUpload(encoding);
try {
List fileItems = ((ServletFileUpload) fileUpload).parseRequest(request);
MultipartParsingResult parsingResult = parseFileItems(fileItems, encoding);
return new DefaultMultipartHttpServletRequest(
request, parsingResult.getMultipartFiles(), parsingResult.getMultipartParameters(), parsingResult.getMultipartParameterContentTypes());
} catch (FileUploadBase.SizeLimitExceededException ex) {
throw new MaxUploadSizeExceededException(fileUpload.getSizeMax(), ex);
}
catch (FileUploadException ex) {
throw new MultipartException("Could not parse multipart servlet request", ex);
}
}
public void cleanupMultipart(MultipartHttpServletRequest request) {
super.cleanupMultipart(request);
}
public void setFileSizeMax(long fileSizeMax) {
getFileUpload().setSizeMax(-1);
getFileUpload().setFileSizeMax(fileSizeMax);
}
}
答案 2 :(得分：0)
首次尝试时，我会在response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR)中致电MaxUploadSizeExceededExceptionHandler。
然后我会检查one或two SO问题，看看它们是否包含我可以试用的一些有用信息。
如果这没有用，我会调查GwtUpload的来源，看看他们是如何实现的（或者只是开始使用他们的实现）。
答案 3 :(得分：0)
yourfile.getFile().getSize() > Long.parseLong(153600);
此代码将批准上传小于150 kb的文件。 如果超过150 kb，您可以发送任何错误消息。