I need to send an email along with an embedded image. Once the email has been sent, the image in the application server should be deleted immediately. The problem I'm facing is, after the email is sent, the control goes method which contain,
File file = new File("../bar.jpeg")
if(file.exists()){
file.delete();
System.out.println("Barcode Image Deleted");
}
It's printing "Barcode Image Deleted". But, the image is not deleted and is still present in the same location. I'm using multipart to attach the image to the email.
Why is it not getting deleted?
Are you using javax.mail?
If so, you'll need to wait till the mail has finished being sent, which you find out about by registering a TransportListener.
This also means you won't be able to use the static Transport.send() methods, but will have to construct and clean up your own session and transport.
I'm trying to remember details from a while ago... I think the DataHandler or DataSource don't close the input stream when they've finished reading it, so you need to keep a reference to it and close it yourself before you can delete the underlying file.
The File.delete method returns a boolean which indicates whether the deletion was successful.
It could be that the file deletion is not being successfully performed due to not having permissions to delete the file.
File.delete() returns a true/false condition. Try checking the return condition of delete to see if the system is actually reporting the file as deleted.
Firstly, File.delete() returns a boolean if it successfully deletes a file. Check that value and at least log it.
If it is not being deleted, then I would guess that either
the file is currently open for reading and the OS won't let you delete it until it is closed. Possible your mail software? My guess is that the mail software does not try to base64 encode the image (for inclusion in the message) until it is actually sending the message...and/or does not stop reading it until the mail is sent.
the java process does not have permissions to delete the file
Related
I am making a simple text-only instant messenger in java. The way that it currently works is that all the messages are put into an online text file by sending a php file a request (I know this is bad for security, but this is just to learn how to do web-connected apps in java.)
Currently, I am continually fetching the entire contents of the messages.txt file and placing them into my JTextPane like this:
while(true) {
URL url = new URL("{path to text file}");
InputStream in = url.openStream();
Scanner s = new Scanner(in).useDelimiter("\\A");
String conversation = s.hasNext() ? s.next() : "";
textPane.setText(conversation);
}
But when the conversation becomes long enough, it lags as it is fetching 100kb+ files constantly from a web server.
What I want to happen is to only read the changes to the file so that it doesn't lag and max out my internet connection by requesting enourmous amounts of plain text files. I don't want to just make it run every 2 seconds because it's an instant messenger, no delays.
How would I go around only fetching the changes to the file and adding them to the text pane?
Can you push the file contents to another file once it crosses a certain threshold. This will ensure that you operate upon a smaller file.
Instead of contacting url directly you could place some server side script that would call the file
You could (as a client) provide the server script the last line / message identifier and the server could respond with new messages that have been added after the message id that the client has provided. In addition it could send the new last message id
With this approach the server side script doesnt even need to read itself the whole file and instead can immediately skip to the required line if message id contains the information about the line in the log file
Of course this approach is really far from real scenarios but its ok for learning IMO
I'm reading and processing emails received from IMAP using JODD mail library. API is very nice but I struggle with one logical issue. I'm using code as following:
EmailFilter filter= new EmailFilter();
filter.flag(Flags.Flag.SEEN, false);
session.receiveEmailAndMarkSeen(filter);
By calling session.receiveEmailAndMarkSeen I receive all unread emails and these are marked as read immediately. Now when processing fails in my code for any reason, and I try to receive emails again all these unprocessed emails are marked as read already and not downloaded anymore. I would rather download emails and mark them as read individualy as beeing processed successfully.
So I tried to receive them with session.receiveEmail but not sure how to mark them as read when processed? Any hint how to do it? I can see that email object has 'flag' property I can set but not sure how to send this information back to server.
To summarize possible solutions:
Re-fetch email with Seen flag. The downside is that email is fetched again.
What you wrote - using a Session and a Folder.
Finally - starting from the next version of Jodd, you will have the method updateEmailFlags that would give you options to just call it:
mymail.flags(newFlags);
ReceiveMailSession.updateEmailFlags(mymail);
The result would be the same.
SOLVED: I'm creating connection manualy using common JAVA mail classes - Session and Store.
Session sess = Session.getDefaultInstance(props, null);
Store store = sess.getStore("imaps");
store.connect("imapServerHost", "username","password");
... then I create folder object (points to Inbox)
Folder folder = store.getFolder(this.imapFolder);
folder.open(Folder.READ_WRITE);
... then I receive emails using session and store
ReceiveMailSession session=new ReceiveMailSession(sess, store);
... after email processed, I send back SEEN=true message using folder object.
Flags f=new Flags();
f.add(Flags.Flag.SEEN);
folder.setFlags(new int[] {email.getMessageNumber()}, f,true);
Im trying to wrap my head around Java Out/Inputstreams, closing and flushing. I have a situation where I want to create a file using Apache POI with data from a server. I would like the file to start downloading as soon as I retrieve the first record from the DB(Show the file at the bottom of the browser has started to download).
public void createExcelFile(final HttpServletResponse response,
final Long vendorId) {
try {
// setup responses types...
final XSSFWorkbook xssfWorkbook = new XSSFWorkbook();
final XSSFSheet sheet = xssfWorkbook.createSheet("sheets1");
// create file with data
writeExcelOutputData(sheet, xssfWorkbook);
xssfWorkbook.write(response.getOutputStream());
xssfWorkbook.close();
}
catch (final Exception e) {
LOGGER.error("Boom");
}
The above code will perform a file download no problem, but this could be a big file. I go off getting the data(around 20/30s) and then after that the download begins < no good...
Can I achive what I need or whats the best approach, thanks in advance
Cheers :)
Reasons could be as following:
maybe there is a read/write timeout with your http server, then if the process gets lengthy or becasue of low-bandwidth, so the connection will be closed by the server.
make sure the process(the excel work) gets completely done, maybe there would be an error/exception during work.
The solution of Jorge looks very promising. User need once request for a file, then server would do the work in background and then either user check the work process and download the file if ready, or server informs the user by email, web notification, etc...
Also you would keep the file in the server in a temp file for a while, and if the connection gets interrupted, server would respond the generated file partial(omit the bytes sent, like normal file download)
Keeping a connection alive to do a lengthy work is not very logical.
Again, if the file gets ready fast(really fast) for download/stream, and the download interrupts, if could be becasue of read/write timeout by server, or a very bad network.
I know the title is a bit confusing. I will describe my task:
Now I'm writing a webpage, which allow me to download some data or do some other stuff. The front end is jsp and the back end is java. So every time when I do something on this page(e.g. sort the data or download the data), a request will be sent to java and after data processing the .jsp page will be refreshed and loaded again(of cause after sorting it should be refreshed). But I just found that if I download a data with the following code, the refreshing will be interrupted:
OutputStream out = response.getOutputStream(); // response is HttpServletResponse
doSomeOutput(out); // Just write something into OutputStream
out.flush(); // **PAY ATTENTION**. The refreshing is interrupted here!
out.close();
When I was debugging, the page was keeping loading until the third line. And then the page was not refreshed and the data was download.
I hope you can understand what I'm talking about:(
So now I have 2 questions: 1. How can I let the process keep working after out.flush();? 2. In my task I need the same behavior(the process is interrupted) in some other modules, but there's nothing to be download. So how can I interrupt the process besides out.flush();?
Thank you guys!!
1)
https://docs.oracle.com/javaee/5/api/javax/servlet/ServletResponse.html#getOutputStream%28%29
"Calling flush() on the ServletOutputStream commits the response"
as i understand this: active refreshing is stopped, as we got main part of data. But you would be able to send data even after commit. So you can keep working after flush.
Set headers are also sent with flush.
2) Pls explain more thoroughly. call "return", or close?
Currently im doing as following,
#Override
public void saveDraftMessage(MimeMessage draftMessage) throws MessagingException
{
Folder draftsMailBoxFolder = imapsStore.getFolder("inbox");//[Gmail]/Drafts
draftsMailBoxFolder.open(Folder.READ_WRITE);
draftMessage.setFlag(Flag.DRAFT, true);
MimeMessage draftMessages[] = {draftMessage};
draftsMailBoxFolder.appendMessages(draftMessages);
}
It works but , as you could see message is being appended to "inbox" folder without complain from server end !
Is there any kind of validation or an alternative method to ensure that message is saved as Draft only at appropriate place.
As others have suggested above, you need to store your draft messages in a different folder. You can choose the name of that folder. If you're only using Gmail and you want to be consistent with what Gmail is doing, saving it in the folder Gmail uses ("[Gmail]/Drafts"?) would make sense. Remember to delete the message from the folder when you send it.