Javamail/email commons：空消息给出奇怪的错误

我正试图通过GMail（实际上是谷歌应用程序）发送电子邮件。这对正常消息非常有效，但我当然必须测试极端情况

BodyPart body = new MimeBodyPart();
body.setText(("Message Body"));
multipart.addBodyPart(body);   // ** here
message.setContent(multipart);
Transport.send(message);

现在我正在尝试发送一条没有正文的消息，我收到一条奇怪的错误消息。当我想消除代码中的错误时，我想知道我是做错了什么，还是我正在使用的库中有错误

HtmlEmail currentMessage = new HtmlEmail();
currentMessage.setSSL(true);
currentMessage.setSslSmtpPort(465);
currentMessage.setHostName("smtp.gmail.com");
currentMessage.setAuthentication("abc@gmail.com", "secret");

/** rs is a ResultSet from database **/

if(rs.getString("mailFrom") != null && !rs.getString("mailFrom").isEmpty())
    currentMessage.setFrom(rs.getString("mailFrom"));
else
    currentMessage.setFrom("abc@gmail.com");
currentMessage.setTo(this.convertRecipientStringToArray(rs.getString("mailTo")));
currentMessage.setCc(this.convertRecipientStringToArray(rs.getString("mailCC")));
currentMessage.setBcc(this.convertRecipientStringToArray(rs.getString("mailBC")));
currentMessage.setSubject(rs.getString("mailSubject"));
if(rs.getString("mailBody") != null && !rs.getString("mailBody").isEmpty())
    currentMessage.setTextMsg(rs.getString("mailBody"));
if(rs.getString("mailHtmlBody") != null && !rs.getString("mailHtmlBody").isEmpty())
    currentMessage.setHtmlMsg(rs.getString("mailHtmlBody"));
if(rs.getString("mailReplyTo") != null && !rs.getString("mailReplyTo").isEmpty())
    currentMessage.addReplyTo(rs.getString("mailReplyTo"));
else
    currentMessage.addReplyTo("def@gmail.com");
currentMessage.send();

BodyPart body = new MimeBodyPart();
body.setText(("Message Body"));
multipart.addBodyPart(body);   // ** here
message.setContent(multipart);
Transport.send(message);

此代码适用于“普通”电子邮件：具有有效的正文、主题、收件人等

BodyPart body = new MimeBodyPart();
body.setText(("Message Body"));
multipart.addBodyPart(body);   // ** here
message.setContent(multipart);
Transport.send(message);

当数据库中的mailBody和mailHtmlBody都为NULL或为空时，我得到以下错误：

BodyPart body = new MimeBodyPart();
body.setText(("Message Body"));
multipart.addBodyPart(body);   // ** here
message.setContent(multipart);
Transport.send(message);

将电子邮件发送到以下服务器失败：smtp.gmail.com:25

BodyPart body = new MimeBodyPart();
body.setText(("Message Body"));
multipart.addBodyPart(body);   // ** here
message.setContent(multipart);
Transport.send(message);

完整错误日志（自己的日志格式）/堆栈跟踪：

[CRITICAL] 2012-12-19 17:08:00 [CET] - Exception occurred in function com.mypackage.mymailobject.outgoing_sendMails: Sending the email to the following server failed : smtp.gmail.com:25

Stack trace:
org.apache.commons.mail.EmailException: Sending the email to the following server failed : smtp.gmail.com:25
    at org.apache.commons.mail.Email.sendMimeMessage(Email.java:1242)
    at org.apache.commons.mail.Email.send(Email.java:1267)
    at com.mypackage.mymailobject.outgoing_sendMails(mymailobject.java:85)
    at com.mypackage.mymailobject.outgoing_do(mymailobject.java:69)
    at com.mypackage.Mailer.main(Mailer.java:132)
Caused by: javax.mail.MessagingException: IOException while sending message;
  nested exception is:
    java.io.IOException: javax.mail.MessagingException: Empty multipart: multipart/mixed; 
    boundary="----=_Part_0_916488860.1355933279096"
    at com.sun.mail.smtp.SMTPTransport.sendMessage(SMTPTransport.java:1141)
    at javax.mail.Transport.send0(Transport.java:195)
    at javax.mail.Transport.send(Transport.java:124)
    at org.apache.commons.mail.Email.sendMimeMessage(Email.java:1232)
    ... 4 more
Caused by: java.io.IOException: javax.mail.MessagingException: Empty multipart: multipart/mixed; 
    boundary="----=_Part_0_916488860.1355933279096"
    at com.sun.mail.handlers.multipart_mixed.writeTo(multipart_mixed.java:105)
    at javax.activation.ObjectDataContentHandler.writeTo(Unknown Source)
    at javax.activation.DataHandler.writeTo(Unknown Source)
    at javax.mail.internet.MimeBodyPart.writeTo(MimeBodyPart.java:1476)
    at javax.mail.internet.MimeMessage.writeTo(MimeMessage.java:1772)
    at com.sun.mail.smtp.SMTPTransport.sendMessage(SMTPTransport.java:1099)
    ... 7 more

BodyPart body = new MimeBodyPart();
body.setText(("Message Body"));
multipart.addBodyPart(body);   // ** here
message.setContent(multipart);
Transport.send(message);

我现在有两个问题：

BodyPart body = new MimeBodyPart();
body.setText(("Message Body"));
multipart.addBodyPart(body);   // ** here
message.setContent(multipart);
Transport.send(message);

是否有可能发送一封没有正文的电子邮件？允许吗

为什么错误消息端口号是25而不是465

---

要使用gmail发送电子邮件，您应该启用传输层安全

currentMessage.setTLS(true);

BodyPart body = new MimeBodyPart();
body.setText(("Message Body"));
multipart.addBodyPart(body);   // ** here
message.setContent(multipart);
Transport.send(message);

---

尽管我找不到相关文档，但经验证明，在Apache Commons电子邮件HtmlEmail对象中不允许使用空的BodyPart。文本消息或html消息应设置为非空字符串

BodyPart body = new MimeBodyPart();
body.setText(("Message Body"));
multipart.addBodyPart(body);   // ** here
message.setContent(multipart);
Transport.send(message);

端口为25的错误消息是Apache Commons电子邮件代码中的一个错误，在打印smtp端口时未考虑SSL。为此，已在以下位置提交了错误报告：

BodyPart body = new MimeBodyPart();
body.setText(("Message Body"));
multipart.addBodyPart(body);   // ** here
message.setContent(multipart);
Transport.send(message);

是否有可能发送一封没有正文的电子邮件？是吗 允许吗

BodyPart body = new MimeBodyPart();
body.setText(("Message Body"));
multipart.addBodyPart(body);   // ** here
message.setContent(multipart);
Transport.send(message);

是的，RFC 5322特别允许电子邮件正文为空：

BodyPart body = new MimeBodyPart();
body.setText(("Message Body"));
multipart.addBodyPart(body);   // ** here
message.setContent(multipart);
Transport.send(message);

“消息由标题字段组成，可选择后跟消息 身体。”

BodyPart body = new MimeBodyPart();
body.setText(("Message Body"));
multipart.addBodyPart(body);   // ** here
message.setContent(multipart);
Transport.send(message);

以下是BNF：

body            =   (*(*998text CRLF) *998text) / obs-body

BodyPart body = new MimeBodyPart();
body.setText(("Message Body"));
multipart.addBodyPart(body);   // ** here
message.setContent(multipart);
Transport.send(message);

---

MIME规范不允许没有主体部分的多部分内容。（从1.5版开始，我想）允许您将系统属性

mail.mime.multipart.allowempty

设置为

true

，以解决此问题。

我遇到了完全相同的异常，但由于一个愚蠢的错误，我忘记了将消息正文添加到多部分消息中。这就是错误

BodyPart body = new MimeBodyPart();
body.setText(("Message Body"));
multipart.addBodyPart(body);   // ** here
message.setContent(multipart);
Transport.send(message);

---

正如我所说，发送邮件与此代码完美结合，所以不是这样。这只是邮件正文为空的特殊情况。此外，我使用SSL而不是TLS。您是否尝试过将消息设置为空字符串是否有效？另外，这是完整的错误消息吗？没有stacktrace或嵌套异常？如果我将消息设置为空字符串，我将从Apache Commons电子邮件中获得另一个异常。见第131行，将stacktrace添加到原始帖子中。：）这有帮助吗？我现在可以回答我自己的帖子了；在commons中Email.java的第1240行，他们使用这个.getSmtpPort（）作为异常消息。如果它涉及SSL连接思想，他们应该使用这个.getSslSmtpPort（）。所以我要在Apache Commons上提交一份bug报告。谢谢你的指导。：）