jsp上传图片到指定空间

<form action="UploadServlet" method="post" enctype="multipart/form-data">
    <input type="file" name="file" />
    <input type="submit" value="上传" />
</form>

import java.io.*;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

public class UploadServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
    private static final String UPLOAD_DIRECTORY = "uploads";

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        if (ServletFileUpload.isMultipartContent(request)) {
            try {
                List<FileItem> multiparts = new ServletFileUpload(new DiskFileItemFactory()).parseRequest(request);
                for (FileItem item : multiparts) {
                    if (!item.isFormField()) {
                        String name = new File(item.getName()).getName();
                        item.write(new File(UPLOAD_DIRECTORY + File.separator + name));
                    }
                }
                response.sendRedirect("success.jsp");
            } catch (Exception ex) {
                request.setAttribute("message", "File Upload Failed due to " + ex);
                request.getRequestDispatcher("/result.jsp").forward(request, response);
            }
        } else {
            request.setAttribute("message", "Sorry this Servlet only handles file upload request");
            request.getRequestDispatcher("/result.jsp").forward(request, response);
        }
    }
}

File uploadDir = new File(UPLOAD_DIRECTORY);
if (!uploadDir.exists()) uploadDir.mkdir();