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| <!-- $Id$ --> |
| <html> |
| <head> |
| <title>Overview of the org.apache.commons.fileupload component</title> |
| </head> |
| <body> |
| <p> |
| A component for handling HTML file uploads as specified by |
| <a href="http://www.ietf.org/rfc/rfc1867.txt" target="_top">RFC 1867</a>. |
| This component provides support for uploads within both servlets (JSR 53) |
| and portlets (JSR 168). |
| </p> |
| <p> |
| 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 |
| {@link org.apache.commons.fileupload.FileUpload FileUpload} such as |
| {@link org.apache.commons.fileupload.servlet.ServletFileUpload ServletFileUpload} |
| or |
| {@link org.apache.commons.fileupload.portlet.PortletFileUpload PortletFileUpload}, |
| together with a factory for |
| {@link org.apache.commons.fileupload.FileItem FileItem} instances, |
| such as |
| {@link org.apache.commons.fileupload.disk.DiskFileItemFactory DiskFileItemFactory}. |
| </p> |
| <p> |
| The following is a brief example of typical usage in a servlet, storing |
| the uploaded files on disk. |
| </p> |
| <pre> |
| public void doPost(HttpServletRequest req, HttpServletResponse res) { |
| DiskFileItemFactory factory = new DiskFileItemFactory(); |
| // maximum size that will be stored in memory |
| factory.setSizeThreshold(4096); |
| // the location for saving data that is larger than getSizeThreshold() |
| factory.setRepository(new File("/tmp")); |
| |
| 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(); |
| // filename on the client |
| String fileName = fi.getName(); |
| // save comment and filename to database |
| ... |
| // write the file |
| fi.write(new File("/www/uploads/", fileName)); |
| } |
| </pre> |
| <p> |
| In the example above, the first file is loaded into memory as a |
| <code>String</code>. Before calling the <code>getString</code> 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. |
| </p> |
| <p> |
| Please see the FileUpload |
| <a href="http://commons.apache.org/fileupload/using.html" target="_top">User Guide</a> |
| for further details and examples of how to use this package. |
| </p> |
| </body> |
| </html> |
