We have discussed the fundamentals of Java Mail API. We discussed the way with which java mail API uses SMTP to send emails with attachment and without attachment.We also discussed the use of POP3 and IMAP in Java Mail API.In the just previous chapter we discussed the way with Java Mail API deletes email.In this post , we are discussing how Java Mail API reads an email with attachment.
Reading email with Attachment in Java
We are accessing Gmail server in our application. We are using IMAP as email retrieving protocol.Our application reads all unread mails from inbox and displays the content in console.If the mail contains attachments , then those attachments will be saved to the ‘downloadDirectory’ folder mentioned in the code.
The following class needs to put in a dynamic web project because Java Mail API is there in J2EE.(If we need to use Java mail API features to J2SE application , then we can download the Java Mail API .It is available here for download.Extract the file and put the jar files in the application path).
ReadMailSample.java
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;
import javax.mail.Address;
import javax.mail.BodyPart;
import javax.mail.Flags;
import javax.mail.Folder;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Multipart;
import javax.mail.NoSuchProviderException;
import javax.mail.Part;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Store;
import javax.mail.Flags.Flag;
import javax.mail.search.FlagTerm;
public class ReadMailSample {
Properties properties = null;
private Session session = null;
private Store store = null;
private Folder inbox = null;
private String userName = "";// provide user name
private String password = "";// provide password
String downloadDirectory = "C:/tmp/downloads/";
public ReadMailSample() {
}
public void readMails() {
properties = new Properties();
properties.setProperty("mail.host", "imap.gmail.com");
properties.setProperty("mail.port", "995");
properties.setProperty("mail.transport.protocol", "imaps");
session = Session.getInstance(properties,
new javax.mail.Authenticator() {
protected PasswordAuthentication getPasswordAuthentication() {
return new PasswordAuthentication(userName, password);
}
});
try {
store = session.getStore("imaps");
store.connect();
inbox = store.getFolder("INBOX");
inbox.open(Folder.READ_ONLY);
Message messages[] = inbox.search(new FlagTerm(
new Flags(Flag.SEEN), false));
;
System.out.println("Number of mails = " + messages.length);
for (int i = 0; i < messages.length; i++) {
Message message = messages[i];
Address[] from = message.getFrom();
System.out.println("-------------------------------");
System.out.println("Date : " + message.getSentDate());
System.out.println("From : " + from[0]);
System.out.println("Subject: " + message.getSubject());
System.out.println("Content :");
processMessageBody(message);
System.out.println("--------------------------------");
}
inbox.close(true);
store.close();
} catch (NoSuchProviderException e) {
e.printStackTrace();
} catch (MessagingException e) {
e.printStackTrace();
}
}
public void processMessageBody(Message message) {
try {
Object content = message.getContent();
// check for string
// then check for multipart
if (content instanceof String) {
System.out.println(content);
} else if (content instanceof Multipart) {
Multipart multiPart = (Multipart) content;
procesMultiPart(multiPart);
} else if (content instanceof InputStream) {
InputStream inStream = (InputStream) content;
int ch;
while ((ch = inStream.read()) != -1) {
System.out.write(ch);
}
}
} catch (IOException e) {
e.printStackTrace();
} catch (MessagingException e) {
e.printStackTrace();
}
}
public void procesMultiPart(Multipart content) {
try {
for (int i = 0; i < content.getCount(); i++) {
BodyPart bodyPart = content.getBodyPart(i);
Object o;
o = bodyPart.getContent();
if (o instanceof String) {
System.out.println("Text = " + o);
} else if (null != bodyPart.getDisposition()
&& bodyPart.getDisposition().equalsIgnoreCase(
Part.ATTACHMENT)) {
String fileName = bodyPart.getFileName();
System.out.println("fileName = " + fileName);
InputStream inStream = bodyPart.getInputStream();
FileOutputStream outStream = new FileOutputStream(new File(
downloadDirectory + fileName));
byte[] tempBuffer = new byte[4096];// 4 KB
int numRead;
while ((numRead = inStream.read(tempBuffer)) != -1) {
outStream.write(tempBuffer);
}
inStream.close();
outStream.close();
}
// else?
}
} catch (IOException e) {
e.printStackTrace();
} catch (MessagingException e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
ReadMailSample sample = new ReadMailSample();
sample.readMails();
}
}
Output
provide username and password of Gmail account . Then Compile and run the above application.The unread mails will be displayed in the console.If any mail contains attachments , then those attachments will be downloaded to the folder 'downloadDirectory'.
See Related Discussions:
Deleting email in Java Mail API
SMTP
POP
IMAP
Hi,
I tried the same code to read the mail content with attachment over IMAP protocol.
If i understood correctly, the above code is getting the mail into parts when mail has an inline attachment and second part will have the information of attachment. First part contains the mail content. So i am trying to read the mail content first part using getContent(). But it returns null.
Any idea why is this issue?
Or else can you provide the working sample code to read the mail content and also the inline attachment over imap.
Attachements can be put in two ways…by attaching to email and by putting that in mail body.
Above code will read attachements that are attached with the mail. In order to ready attachements in body you need to put additional conditions as below
part.getFileName() != null && (part.getDisposition() == null || part.getDisposition().equals(ATTACHMENT));
This will help to read attachements that are in body.
Hi,
1)Null pointer exception will come if there is no new email or unread email,
2)the code has some issue, it will not download the attachment, it will just read the name of the attachment.
@Author
Please post some other solution if you have.