由于多种原因,邮件可能会被退回.只有服务器才能确定是否存在特定邮箱或用户名.当服务器检测到错误时,它会向原始邮件的发件人返回一条消息,指出失败的原因.
有许多Internet标准涵盖了传递状态通知但是大量的服务器不支持这些新标准,而是使用ad hoc技术返回此类故障消息.因此,很难将退回的消息与导致问题的原始消息相关联.
JavaMail包括对解析传递状态通知的支持.有许多技术和启发式方法可以解决这个问题.其中一种技术是可变包络返回路径.您可以在信封中设置返回路径,如下例所示.这是发送退回邮件的地址.您可能希望将其设置为与From:标头不同的通用地址,以便您可以处理远程反弹.这是通过在JavaMail中设置 mail.smtp.from 属性来完成的.
创建一个java类文件 SendEmail ,其内容如下:
import java.util.Properties; import javax.mail.Message; import javax.mail.PasswordAuthentication; import javax.mail.Session; import javax.mail.Transport; import javax.mail.internet.InternetAddress; import javax.mail.internet.MimeMessage; public class SendEmail { public static void main(String[] args) throws Exception { String smtpServer = "smtp.gmail.com"; int port = 587; final String userid = "youraddress";//change accordingly final String password = "*****";//change accordingly String contentType = "text/html"; String subject = "test: bounce an email to a different address " + "from the sender"; String from = "youraddress@gmail.com"; String to = "bouncer@fauxmail.com";//some invalid address String bounceAddr = "toaddress@gmail.com";//change accordingly String body = "Test: get message to bounce to a separate email address"; Properties props = new Properties(); props.put("mail.smtp.auth", "true"); props.put("mail.smtp.starttls.enable", "true"); props.put("mail.smtp.host", smtpServer); props.put("mail.smtp.port", "587"); props.put("mail.transport.protocol", "smtp"); props.put("mail.smtp.from", bounceAddr); Session mailSession = Session.getInstance(props, new javax.mail.Authenticator() { protected PasswordAuthentication getPasswordAuthentication() { return new PasswordAuthentication(userid, password); } }); MimeMessage message = new MimeMessage(mailSession); message.addFrom(InternetAddress.parse(from)); message.setRecipients(Message.RecipientType.TO, to); message.setSubject(subject); message.setContent(body, contentType); Transport transport = mailSession.getTransport(); try { System.out.println("Sending ...."); transport.connect(smtpServer, port, userid, password); transport.sendMessage(message, message.getRecipients(Message.RecipientType.TO)); System.out.println("Sending done ..."); } catch (Exception e) { System.err.println("Error Sending: "); e.printStackTrace(); } transport.close(); }// end function main() }
这里我们可以看到属性 mail.smtp.from 设置与 from 地址不同.
现在我们的班级准备好了,让我们编译上面的类.我已将类SendEmail.java保存到目录:/home/manisha/JavaMailAPIExercise .我们需要类路径中的jar javax.mail.jar 和 activation.jar .执行以下命令从命令提示符编译类(两个jar放在/home/manisha/目录中):
javac -cp/home/manisha/activation.jar:/home/manisha/javax.mail.jar:SendEmail.java
既然已经编译了类,那么执行下面的命令运行:
java -cp/home/manisha/activation.jar:/home/manisha/javax.mail.jar:SendEmail
您应该在命令控制台上看到以下消息:
Sending .... Sending done ...