FileSizeLimitExceededException while uploading file greater than allowed limit

问题

public static void parseUpload(HttpServletRequest request) throws AttachmentException
{
    if (ServletFileUpload.isMultipartContent(request))
{
    DiskFileItemFactory factory = new DiskFileItemFactory();
    factory.setSizeThreshold(10 * 1024 * 1024); // 10 MB
    ServletFileUpload uploader = new ServletFileUpload(factory);

    uploader.setSizeMax(3 * 1024 * 1024); // allowed file size
    uploader.setFileSizeMax(3 * 1024 * 1024);

    List<FileItem> items;
    try
    {
        items = uploader.parseRequest(request); // throws exception
        for (FileItem fileItem : items)
        {

        }
    }
    catch (FileUploadBase.FileSizeLimitExceededException e)
    {
        // catch block 1 (stack trace printed)
        throw new AttachmentException(e); // This is being caught in JSP
    }
    catch (FileUploadException e)
    {
        // catch block 2
    }
    catch (Exception e)
    {
        // catch block 3
    }
}
}

I am calling this function from a JSP and things work just fine when I'm uploading a file with size less than 3 MBs.

The moment I upload a file with size greater than 3 MBs the catch block catches the exception but web server returns 502. The application is deployed on JETTY.

The application hangs for a moment and the amount of delay is proportional to the size of attachment.

Exception trace:

parseUpload <@> FileSizeLimitExceededException with error message : The field urlname exceeds its maximum permitted size of 3145728 bytes. 
org.apache.commons.fileupload.FileUploadBase$FileItemIteratorImpl$FileItemStreamImpl$1.raiseError(FileUploadBase.java:789)
org.apache.commons.fileupload.util.LimitedInputStream.checkLimit(LimitedInputStream.java:78) 
org.apache.commons.fileupload.util.LimitedInputStream.read(LimitedInputStream.java:137)
java.io.FilterInputStream.read(FilterInputStream.java:107) 
org.apache.commons.fileupload.util.Streams.copy(Streams.java:100)
org.apache.commons.fileupload.util.Streams.copy(Streams.java:70)
org.apache.commons.fileupload.FileUploadBase.parseRequest(FileUploadBase.java:347) 
org.apache.commons.fileupload.servlet.ServletFileUpload.parseRequest(ServletFileUpload.java:115)
parseUpload(UploadUtils.java:255)

It seems that however the exception is caught the file is still getting parsed or some other exception has been thrown again.

I have gone through similar posts but none provides the exact reason for this and how to handle this case. Please provide some help here.

来源：https://stackoverflow.com/questions/46814571/filesizelimitexceededexception-while-uploading-file-greater-than-allowed-limit

标签

java

exception-handling

jetty

multipartform-data

apache-commons-fileupload