声明ServletFileUpload对象的正确方法是( )。
A.
ServletFileUpload upload=new ServletFileUpload()
B.
FileItemFactory factory=new FileItemFactory() ServletFileUpload upload=new ServletFileUpload(factory)
C.
FileItemFactory factory=new DiskFileItemFactory() ServletFileUpload upload=new ServletFileUpload(factory);
D.
ServletFileUpload() 无需实例化,可直接使用