使用 IMAP 从 GMail 获取邮件到 Java 应用程序

我想使用 JavaMail和 IMAP从 Java 应用程序访问 Gmail 中的消息。为什么我要做 一个 href = “ https://docs.oracle.com/javase/7/docs/api/java/net/SocketTimeoutException.html”rel = “ nofollow noReferrer”> SocketTimeoutException ？

这是我的代码:

Properties props = System.getProperties();
props.setProperty("mail.imap.host", "imap.gmail.com");
props.setProperty("mail.imap.port", "993");
props.setProperty("mail.imap.connectiontimeout", "5000");
props.setProperty("mail.imap.timeout", "5000");


try {
Session session = Session.getDefaultInstance(props, new MyAuthenticator());
URLName urlName = new URLName("imap://MYUSERNAME@gmail.com:MYPASSWORD@imap.gmail.com");
Store store = session.getStore(urlName);
if (!store.isConnected()) {
store.connect();
}
} catch (NoSuchProviderException e) {
e.printStackTrace();
System.exit(1);
} catch (MessagingException e) {
e.printStackTrace();
System.exit(2);
}

我已经设置了超时值，这样就不会“永远”超时。此外，MyAuthenticator还有用户名和密码，这对 URL 来说似乎是多余的。还有别的方法来指定协议吗？(我在 JavaDoc 的 IMAP中没有看到它。)

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小开

You have to connect to GMail using SSL only. Setting the following properties will force that for you. 

props.setProperty("mail.imap.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
props.setProperty("mail.imap.socketFactory.fallback", "false");
小开

In JavaMail, you can use imaps as the URL scheme to use IMAP over SSL. (See SSLNOTES.txt in your JavaMail distribution for more details.) For example, imaps://username%40gmail.com@imap.gmail.com/INBOX.

Similarly, use smtps to send emails via Gmail. e.g., smtps://username%40gmail.com@smtp.gmail.com/. Again, read SSLNOTES.txt for more details. Hope it helps!

小开

Using imaps was a great suggestion. Neither of the answers provided just worked for me, so I googled some more and found something that worked. Here's how my code looks now.

Properties props = System.getProperties();
props.setProperty("mail.store.protocol", "imaps");
try {
Session session = Session.getDefaultInstance(props, null);
Store store = session.getStore("imaps");
store.connect("imap.gmail.com", "<username>@gmail.com", "<password>");
...
} catch (NoSuchProviderException e) {
e.printStackTrace();
System.exit(1);
} catch (MessagingException e) {
e.printStackTrace();
System.exit(2);
}

This is nice because it takes the redundant Authenticator out of the picture. I'm glad this worked because the SSLNOTES.txt make my head spin.

小开

Check http://g4j.sourceforge.net/. There is a minimal gmail client built using this API.

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If you'd like more sample code on using JavaMail with Gmail (e.g. converting Gmail labels to IMAP folder names, or using IMAP IDLE), do check out my program GmailAssistant on SourceForge.

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URLName server = new URLName("imaps://<gmail-user-name>:<gmail-pass>@imap.gmail.com/INBOX");
小开

I used following properties to get the store and It works well.

"mail.imaps.host" : "imap.gmail.com"
"mail.store.protocol" : "imaps"
"mail.imaps.port" : "993"

小开

You need to have JSSE installed to use SSL with Java

小开

You need to use the following properties for imaps:

props.setProperty("mail.imaps.host", "imap.gmail.com");
props.setProperty("mail.imaps.port", "993");
props.setProperty("mail.imaps.connectiontimeout", "5000");
props.setProperty("mail.imaps.timeout", "5000");

Notices it's "imaps", not "imap", since the protocol you're using is imaps (IMAP + SSL)

小开

Here is what worked for my team and I, given a classic account nickname@gmail.com and a business account employee@business.com :

            final Properties properties = new Properties();
properties.put("mail.imap.ssl.enable", "true");


imapSession = Session.getInstance(properties, null);
imapSession.setDebug(false);
imapStore = imapSession.getStore("imap");


imapStore.connect("imap.gmail.com", USERNAME, "password");

with USERNAME = "nickname" in the classic case, and USERNAME = "employee@business.com" in the business account case.

In the classic case, don't forget to lower the account security here : https://www.google.com/settings/security/lesssecureapps

In both cases check in GMail Settings => Forwarding POP / IMAP if IMAP is enabled for the account.

Hope it helps!

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