Java Mail不支持电子邮件主题中的UTF-8字符

以下是我的电子邮件设置代码：

String bodyMessage="Dear Renavçilçleç Françoisç InCites™"; String subject = "Your new InCites™ subscription"; Properties _sessionProperties = new Properties(); _sessionProperties.put("mail.transport.protocol", "smtp"); _sessionProperties.put("mail.smtp.host", "hostname"); _sessionProperties.put("mail.smtp.port", "25"); Session session = Session.getInstance(_sessionProperties, null); MimeMessage mimemsg = new MimeMessage(session); mimemsg.addRecipients(Message.RecipientType.TO, "[e-mail]"); mimemsg.setSubject(subject, "UTF-8"); // Create a multi-part message MimeMultipart multipart = new MimeMultipart(); // Set the subType multipart.setSubType("alternative"); BodyPart part = new MimeBodyPart(); part.setContent(bodyMessage, "charset=UTF-8"); // Set the emailBody and emailType to MIME BodyPart part.setDataHandler(new DataHandler(new ByteArrayDataSource( bodyMessage, "text/html;"))); // Add the MIME BodyPart to MIME multiPart multipart.addBodyPart(part); // Put parts in message mimemsg.setContent(multipart); // Send message Transport.send(mimemsg); 

但仍然在电子邮件主题中，它仍显示为"Your new InCites™ subscription"

Answer 1

你在这里提到的主题完全由ASCII字符组成。 这包括有趣的特殊角色™ 。 如果您希望它是Unicode，只需使用Unicode而不是HTML转义。 邮件与HTML没有任何关系。

 mimemsg.setSubject("Your new InCites\u2122 subscription", "UTF-8"); 

这应该将主题编码为=?UTF-8?Q?Your...subscription?= ，如RFC 2047中所规定。

完整的示例代码：

 package so4406538; import java.io.IOException; import java.util.Properties; import javax.mail.MessagingException; import javax.mail.Session; import javax.mail.internet.MimeMessage; public class MailDemo { public static void main(String[] args) throws MessagingException, IOException { Properties props = new Properties(); Session session = Session.getDefaultInstance(props); MimeMessage message = new MimeMessage(session); message.setSubject("Your new InCites\u2122 subscription", "UTF-8"); message.setContent("hello", "text/plain"); message.writeTo(System.out); } } 

输出：

 Message-ID: <7888229.0.1291967222281.JavaMail.roland@bacc> Subject: =?UTF-8?Q?Your_new_InCites=E2=84=A2_subscription?= MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit hello 

您可以看到主题标题已编码，这是必要且正确的。

[ 更新：我修复了Unicode转义序列，如我的一条评论所示。]