# Package org.apache.commons.fileupload2.core

package org.apache.commons.fileupload2.core

A component for handling HTML file uploads as specified by RFC 1867. This component provides support for uploads within both servlets (JSR 53) and portlets (JSR 168).

While this package provides the generic functionality for file uploads, these classes are not typically used directly. Instead, normal usage involves one of the provided extensions of `AbstractFileUpload` such as `org.apache.commons.fileupload2.core.servlet.ServletFileUpload ServletFileUpload` or `org.apache.commons.fileupload2.core.portlet.PortletFileUpload PortletFileUpload`, together with a factory for `FileItem` instances, such as `DiskFileItemFactory`.

The following is a brief example of typical usage in a servlet, storing the uploaded files on disk.

     public void doPost(HttpServletRequest req, HttpServletResponse res) {
       DiskFileItemFactory factory = new DiskFileItemFactory.builder()
         // maximum size that will be stored in memory
         .setSizeThreshold(4096);
         // the location for saving data that is larger than getSizeThreshold()
         .setPath(Paths.get("/tmp"))
         // build it
         .get();

       ServletFileUpload upload = new ServletFileUpload(factory);
       // maximum size before a FileUploadException will be thrown
       upload.setSizeMax(1000000);

       List fileItems = upload.parseRequest(req);
       // assume we know there are two files. The first file is a small
       // text file, the second is unknown and is written to a file on
       // the server
       Iterator i = fileItems.iterator();
       String comment = ((FileItem)i.next()).getString();
       FileItem fi = (FileItem)i.next();
       // file name on the client
       String fileName = fi.getName();
       // save comment and file name to database
       ...
       // write the file
       fi.write(new File("/www/uploads/", fileName));
     }

In the example above, the first file is loaded into memory as a `String`. Before calling the `getString` method, the data may have been in memory or on disk depending on its size. The second file we assume it will be large and therefore never explicitly load it into memory, though if it is less than 4096 bytes it will be in memory before it is written to its final location. When writing to the final location, if the data is larger than the threshold, an attempt is made to rename the temporary file to the given location. If it cannot be renamed, it is streamed to the new location.

Please see the FileUpload User Guide for further details and examples of how to use this package.

- Class
  Description
  AbstractFileUpload<R,I extends FileItem<I>,F extends FileItemFactory<I>>
  High level API for processing file uploads.
  AbstractRequestContext<T>
  DiskFileItem
  The default implementation of the `FileItem` interface.
  DiskFileItem.Builder
  Builds a new `DiskFileItem` instance.
  DiskFileItemFactory
  The default `FileItemFactory` implementation.
  DiskFileItemFactory.Builder
  Builds a new `DiskFileItemFactory` instance.
  FileItem<F extends FileItem<F>>
  This class represents a file or form item that was received within a `multipart/form-data` POST request.
  FileItemFactory<I extends FileItem<I>>
  Creates `FileItem` instances.
  FileItemFactory.AbstractFileItemBuilder<I extends FileItem<I>,B extends FileItemFactory.AbstractFileItemBuilder<I,B>>
  Abstracts building for subclasses.
  FileItemHeaders
  This class provides support for accessing the headers for a file or form item that was received within a `multipart/form-data` POST request.
  FileItemHeadersProvider<T extends FileItemHeadersProvider<T>>
  Provides access to headers.
  FileItemInput
  Provides access to a file or form item that was received within a `multipart/form-data` POST request.
  FileItemInput.ItemSkippedException
  This exception is thrown, if an attempt is made to read data from the `InputStream`, which has been returned by `FileItemInput.getInputStream()`, after `Iterator.hasNext()` has been invoked on the iterator, which created the `FileItemInput`.
  FileItemInputIterator
  An iterator, as returned by `AbstractFileUpload.getItemIterator(RequestContext)`.
  FileUploadByteCountLimitException
  Signals that a file size exceeds the configured maximum.
  FileUploadContentTypeException
  Signals that a request is not a multipart request.
  FileUploadException
  Signals errors encountered while processing the request.
  FileUploadFileCountLimitException
  Signals that a request contains more files than the specified limit.
  FileUploadSizeException
  Signals that a requests permitted size is exceeded.
  MultipartInput
  Low-level API for processing file uploads.
  MultipartInput.Builder
  Builds a new `MultipartInput` instance.
  MultipartInput.FileUploadBoundaryException
  Signals an attempt to set an invalid boundary token.
  MultipartInput.MalformedStreamException
  Signals that the input stream fails to follow the required syntax.
  MultipartInput.ProgressNotifier
  Internal class, which is used to invoke the `ProgressListener`.
  ParameterParser
  A simple parser intended to parse sequences of name/value pairs.
  ProgressListener
  Receives progress information.
  RequestContext
  Abstracts access to the request information needed for file uploads.