关于Servlet上传文件的问题

@MultipartConfig(location = "i:/")
@WebServlet( "/UploadServlet3")
public class UploadServlet3 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        request.setCharacterEncoding("UTF-8");
        for (Part part : request.getParts()) {
            if(part.getName().startsWith("file")){
                part.write(getFilename(part));
            }
        }
    }
    private String getFilename(Part part){
        String header=part.getHeader("Content-Disposition");
        String filename=header.substring(header.indexOf("filename=\""),header.lastIndexOf("\""));
        return filename;
    }
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    }
}