Step1:Defining a data class named Photo
public class Photo{
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
private Long id;
@Persistent
private Blob photo;
...
Set & Get
...
}
Step2:Defining a DAO PhotoDAO.java
public class PhotoDao {
private static PhotoDao _instance = null;
public static PhotoDao getInstance() {
if (_instance == null) {
_instance = new PhotoDao();
}
return _instance;
}
//
public String insertPhoto(Photo photo) {
PersistenceManager pm = PMF.get().getPersistenceManager();
try {
pm.makePersistent(photo);
} finally {
pm.close();
}
return photo.getId().toString();
}
}
Step3:UploadServlet.java
import org.apache.commons.fileupload.FileItemIterator;
import org.apache.commons.fileupload.FileItemStream;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.commons.io.IOUtils;
UploadServlet.java
...
...
ServletFileUpload upload = new ServletFileUpload();
FileItemIterator iterator = null;
try {
iterator = upload.getItemIterator(req);
} catch (FileUploadException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
while (iterator.hasNext()) {
FileItemStream item = iterator.next();
InputStream stream = item.openStream();
if (item.isFormField()) {
// Handle form field
} else {
// Handle the uploaded file
Blob bImg = new
Blob(IOUtils.toByteArray(stream));
Photo photo = new Photo(bImg);
String pid =
PhotoDao.getInstance().insertPhoto(photo);
//resp.sendRedirect("admin?type=photo&option=list");
}
}
...
...
Step4: Show the photo which you upload. PhotoSerlvet.java
public class PhotoServlet extends HttpServlet {
public void doGet(HttpServletRequest req, HttpServletResponse resp)
throws IOException {
String id = req.getParameter("id");
...
Photo photo =
PhotoDao.getInstance().getById(Long.parseLong(id));
...
Blob b = photo.getPhoto();
resp.setContentType("image/jpeg;charset=utf-8");
resp.getOutputStream().write(b.getBytes());
resp.getOutputStream().close();
}
}
demo: http://mimaiji.appspot.com/photo?id=4001
On 3月14日, 下午1时12分, nag <[email protected]> wrote:
> Hi
> I am trying to build online reg form
> can u help me how to upload image files to app engine.
>
> First: is there any way to upload images in app engine?
>
> thanks
> Nag
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