java web文件上传！

     The default FileItemFactory implementation. This implementation creates FileItem instances which keep their content either in memory, for smaller items, or in a temporary file on disk, for larger items. The size threshold, above which content will be stored on disk, is configurable, as is the directory in which temporary files will be created

 那个默认的FileItemFactory实现。这个实现创造了保持了他们的内容FileItem 实例，为了我更小的部件，在临时的文件在硬盘上，或为了更大的部件。开端的大小，以上的内容将会在存在硬盘上，

An abstract representation of file and directory pathnames.

User interfaces and operating systems use system-dependent pathname strings to name files and directories. This class presents an abstract, system-independent view of hierarchical pathnames. An abstract pathname has two components:

1. An optional system-dependent prefix string, such as a disk-drive specifier, "/" for the UNIX root directory, or "\\\\" for a Microsoft Windows UNC pathname, and
2. A sequence of zero or more string names.

The first name in an abstract pathname may be a directory name or, in the case of Microsoft Windows UNC pathnames, a hostname. Each subsequent name in an abstract pathname denotes a directory; the last name may denote either a directory or a file. The  empty abstract pathname has no prefix and an empty name sequence.

 一个抽象的文件代表和目录名。

  用户的接口和操作系统使用系统的独立路径名

1.一个属性的系统的的前缀，比如一个磁盘驱动