blocks|key|360719|text|您不能可靠或始终如一地做到这一点。如果您的本地邮件服务器将其传递到公司的传出邮件服务器，然后当该服务器试图传递它时它会弹回，会发生什么情况？如果邮件服务器无法与其他邮件服务器通信，并且消息在4天后超时，会发生什么情况？|type|unstyled|depth|inlineStyleRanges|entityRanges|data|360720|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

You can't do this reliably or consistently. What happens if your local mail server passes it onto a corporate out-going mail server, and then it bounces when that server tries to pass it on? What happens if the mail server can't talk to the other mail server and then the message times out after 4 days?

blocks|key|365405|text|如果您正在发送HTML电子邮件，您可能希望在电子邮件中嵌入一个1像素的透明图像。图像URL实际上会引用一个返回图像的servlet。URL还将具有某种类型的消息id作为参数。这背后的想法是，当用户阅读消息时，他/她显示图像，这触发了您的servlet，该servlet向数据库写入消息已被读取。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|365406|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

If you're sending out HTML email, you might want to embed a 1 pixel transparent image in the email. The image URL would actually reference a servlet that returns the image. The URL would also have some sort of message id as a parameter.
The idea behind this is that when the user reads the message, he/she displays the image, which triggers your servlet, which writes to the db that the message had been read.

blocks|key|362089|text|您需要做的是将信封SMTP发件人设置为您监视NDR邮件的地址。您必须在收到电子邮件时对其进行分析，找出哪里出了问题。这通常用于邮件列表，并使用像ListNanny这样的产品来处理消息(它是一个.NET产品，但我相信有一个与之相当的产品，或者您也可以自己编写它)。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|362090|信封“发件人”与邮件“发件人”地址不同。它是发生在代码和MTA之间的SMTP会话的一部分。所有NDR都将发送到该地址。|362091|entityMap|0|LINK|mutability|MUTABLE|url|http://www.listnanny.net/^0|20|9|0|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@$A|O|B|P|1|Q]]|C|$]]|$1|D|3|E|5|6|7|R|8|@]|9|@]|C|$]]|$1|F|3|-4|5|6|7|S|8|@]|9|@]|C|$]]]|G|$H|$5|I|J|K|C|$L|M]]]]

What you have to do is set the envelope SMTP sender to an address you monitor for NDR messages. You have to parse the emails as they come in and figure out what went wrong. This is commonly done for mailing lists, and products like <a href="http://www.listnanny.net/" rel="nofollow noreferrer">ListNanny</a> are used to process the messages (it's a .NET product, but I'm sure there is a Java equivalent, or you could write it yourself).

The envelope "from" is different than the message "from" address. It's part of the SMTP conversation that happens between your code and your MTA. All NDRs will be sent to that address.

blocks|key|365391|text|查找邮件服务器并进行连接:很简单。检查帐户:有可能。但这取决于您首先是否获得了访问邮件服务器的权限。它可能会拒绝您的连接尝试(例如，因为您的网络被列入黑名单)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|365392|最复杂的事情是你所说的“成功”：|365393|简短的回答是:不。|365394|长答案:理论上这是可能的，但你必须等待几个小时，如果不是几天的话才能知道状态。有了灰名单，白名单，垃圾邮件拦截服务器，许多人只会在几次发送尝试后才接受一封电子邮件。只有当他们最终投递或放弃邮件时，您才会知道投递成功。并且根据邮件服务器负载，电子邮件的发送可以被推迟任意时间量。|365395|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|L|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|M|8|@]|9|@]|A|$]]|$1|H|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|I|$]]

Finding the mail server and connecting: easy. Checking for an account: possible. But it depends on whether you get access to the mail server in the first place. It may decline your connection attempts (e.g. because your network is blacklisted)

The most complicated thing is what you call "success":

Short answer: No.

Long answer: Theoretically it would be possible, but you would have to wait for hours if not days to know the status. With graylisting, whitelisting, spam-blocking mail servers many will only accept an email after several delivery attempts. You will only know about delivery success when they have finally delivered or given up on the mail. And depending on mail server load the sending of an email may be postponed for an arbitrary amount of time.

blocks|key|360722|text|我并不是特别熟悉Javamail，但我要说的是:即使“成功”也不一定是成功。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|360723|您对硬故障和软故障的定义应该足够简单，以便检查。如果你找不到服务器，那就是硬的；如果你连接网络，服务器说“邮箱找不到”，那就是“软”。但是，如果服务器接受消息，然后稍后将其退回，该怎么办？许多前端服务器接受未知消息，无论是出于设计还是必要(“真正的”后端服务器的前端中继)，并且如果后来发现消息被寻址到无效地址，则消息被退回到发送者。在这种情况下，您将报告发送“成功”，而实际上发送并不成功。|360724|在消息中嵌入某种“单击此处”的情况下，确保交付几乎是不可能的。|360725|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|H|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|I|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|J|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|G|$]]

I'm not famliar specifically w/Javamail, but I would say this: Even "success" may not be success. 

You're definition of hard and soft failures should be simple enough to check. If you can't find a server it's hard, if you connet and the server says "mailbox not found" it's "soft". But what if the server accepts the message and then bounces it later? Many front-end servers accept unknown messages, either by design or necessity (front end relay for "real" backend servers) and if the message is later found to be addressed to an invalid address the message is bounced back to the sender. In that case you'll have reported a "success" in sending when it's really not successful.

Ensuring delivery is next to impossible w/out some sort of "click here" embedded in the message.

blocks|key|3152969|text|不要依赖于你从服务器上得到的信息。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3152970|由于其造成的安全漏洞，许多邮件服务器现在都设置为而不是来指示收件人是否存在。(例如，如果给定域报告电子邮件地址的存在(“是”/“否”)，黑客将简单地在服务器上释放字典攻击以确定所有有效用户，并且因此他们获得即时垃圾邮件列表。|offset|length|style|BOLD|3152971|entityMap^0|0|O|3|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@$D|L|E|M|F|G]]|9|@]|A|$]]|$1|H|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|I|$]]

Don't rely on what you get back (if you get back) info from a server.

Many mail servers are now set up to not indicate whether the receipient exists or not, due the the security hole it creates. (e.g. if a given domain is reporting ("yes"/"no") for the existence of an email address, a hacker would simply unleash a dictionary attack on the server to determine all the valid users, and thus they get an instant spam list.

blocks|key|3365893|text|您可以使用免费服务来检查您的电子邮件是否已被阅读，以及该用户已阅读了多少次。这是一项免费服务。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3365894|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

You can use <a href="http://www.mailcounter.info" rel="nofollow noreferrer">http://www.mailcounter.info</a> free service to check whether your email has been read as well as how many times it has been read by t he user. Its a free service.

blocks|key|3152980|text|您应该做的是实际检查收件人的电子邮件的MX记录(电子邮件地址的域部分的DNS+MX查询)，并通过已解析的SMTP服务器发送邮件。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3152981|这样，如果没有找到MX记录，你就会得到一个“硬反弹”，如果找到了，但是send方法抛出一个异常，你就会得到一个“软反弹”，如果它成功了，你就会得到一个“成功”。|3152982|您可以使用dnsjava项目来解析MX记录。http://www.dnsjava.org/|offset|length|3152983|entityMap|0|LINK|mutability|MUTABLE|url|http://www.dnsjava.org/^0|0|0|M|N|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|Q|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|R|8|@]|9|@$F|S|G|T|1|U]]|A|$]]|$1|H|3|-4|5|6|7|V|8|@]|9|@]|A|$]]]|I|$J|$5|K|L|M|A|$N|O]]]]

what you should do is actually check the MX record of the recipient's email (DNS MX query of the domain portion of the email address) and send the message via the SMTP server that is resolved.

this way, if the MX record is not found, you get a "Hard Bounce", if it is found but the send method throws an exception, you get a "Soft Bounce", and if it goes through - you get a "Success".

you can use the dnsjava project to resolve the MX record.
<a href="http://www.dnsjava.org/" rel="nofollow noreferrer">http://www.dnsjava.org/</a>

blocks|key|362102|text|此link可能会对您有所帮助。这是一个实验jar文件，它使用RFC3642和RFC3464。它有一些基本的类，可以让你获得邮件的传递状态。您还需要Javamail+jar文件。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|362103|entityMap|0|LINK|mutability|MUTABLE|url|http://edelstein.pebbles.cs.cmu.edu/jadeite/main.php?api=javamail&state=package&package=com.sun.mail.dsn|1|http://www.oracle.com/technetwork/java/faq-135477.html#1^0|1|4|0|21|8|1|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@$A|O|B|P|1|Q]|$A|R|B|S|1|T]]|C|$]]|$1|D|3|-4|5|6|7|U|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]|L|$5|G|H|I|C|$J|M]]]]

This <a href="http://edelstein.pebbles.cs.cmu.edu/jadeite/main.php?api=javamail&amp;state=package&amp;package=com.sun.mail.dsn" rel="nofollow">link</a> might helps you. This in an experimental jar file which uses RFC 3642 and RFC 3464. It has some basic classes which allows you to get the mail delivery status. And also you'll need <a href="http://www.oracle.com/technetwork/java/faq-135477.html#1" rel="nofollow">Javamail</a> jar file.

Using Java mail, I would like to send an e-mail and check the status. Possible statuses include:
<ul>
<li>Hard-bounce: No mail server found</li>
<li>Soft-bounce: Mail server found, but account not found</li>
<li>Success</li>
</ul>
Is it even possible to send an e-mail and get some feedback about the delivery attempt in the manner I've described above?
EDIT: A respondent suggested looking for a Java library that provides the same functionality as <a href="http://www.listnanny.net/" rel="nofollow noreferrer">ListNanny</a>. I've searched around, but haven't found anything. Any idea if such a library exists?

send e-mail and check status

数据库

服务器

Java

使用Java邮件，我想发送一封电子邮件并检查状态。可能的状态包括：邮件服务器硬退回:未找到邮件服务器foundSoft-bounce：，但帐户不是foundSuccess有没有可能用我上面描述的方式发送一封电子邮件，并获得一些关于交付尝试的反馈？编辑：一位受访者建议寻找一个提供与相同功能的Java库。我找遍了，但什么也没找到。你知道这样的库是否存在吗？

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