Javamail Api 简明教程

JavaMail API - Replying Emails

在本章中,我们将学习如何使用 JavaMail API 回复电子邮件。下面程序中遵循的基本步骤:

  1. 在属性中获取具有 POP 和 SMPT 服务器详细信息的会话对象。我们需要 POP 详细信息来检索邮件,需要 SMPT 详细信息来发送邮件。

  2. 创建 POP3 存储对象并连接到存储。

  3. 创建 Folder 对象并在邮箱中打开适当的文件夹。

  4. Retrieve messages.

  5. 遍历邮件并输入“Y”或“y”,以表示是否要回复。

  6. 获取邮件的所有信息(收件人、发件人、主题、内容)。

  7. 使用 Message.reply() 方法构建回复邮件。此方法使用适当的收件人和主题配置新的邮件。该方法使用一个布尔参数,表示仅回复发件人(false)还是回复所有人(true)。

  8. 在邮件中设置发件人、文本和回复地址并通过 Transport 对象的实例将其发送出去。

  9. 依次关闭 Transport、folder 和 store 对象。

Create Java Class

创建 java 类文件 ReplyToEmail ,其内容如下:

package com.tutorialspoint;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Date;
import java.util.Properties;

import javax.mail.Folder;
import javax.mail.Message;
import javax.mail.Session;
import javax.mail.Store;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;

public class ReplyToEmail {
   public static void main(String args[])
   {
      Date date = null;

      Properties properties = new Properties();
      properties.put("mail.store.protocol", "pop3");
      properties.put("mail.pop3s.host", "pop.gmail.com");
      properties.put("mail.pop3s.port", "995");
      properties.put("mail.pop3.starttls.enable", "true");
      properties.put("mail.smtp.auth", "true");
      properties.put("mail.smtp.starttls.enable", "true");
      properties.put("mail.smtp.host", "relay.jangosmtp.net");
      properties.put("mail.smtp.port", "25");
      Session session = Session.getDefaultInstance(properties);

      // session.setDebug(true);
      try
      {
         // Get a Store object and connect to the current host
         Store store = session.getStore("pop3s");
         store.connect("pop.gmail.com", "xyz@gmail.com",
            "*****");//change the user and password accordingly

         Folder folder = store.getFolder("inbox");
         if (!folder.exists()) {
            System.out.println("inbox not found");
               System.exit(0);
         }
         folder.open(Folder.READ_ONLY);

         BufferedReader reader = new BufferedReader(new InputStreamReader(
            System.in));

         Message[] messages = folder.getMessages();
         if (messages.length != 0) {

            for (int i = 0, n = messages.length; i < n; i++) {
               Message message = messages[i];
               date = message.getSentDate();
               // Get all the information from the message
               String from = InternetAddress.toString(message.getFrom());
               if (from != null) {
                  System.out.println("From: " + from);
               }
               String replyTo = InternetAddress.toString(message
	         .getReplyTo());
               if (replyTo != null) {
                  System.out.println("Reply-to: " + replyTo);
               }
               String to = InternetAddress.toString(message
	         .getRecipients(Message.RecipientType.TO));
               if (to != null) {
                  System.out.println("To: " + to);
               }

               String subject = message.getSubject();
               if (subject != null) {
                  System.out.println("Subject: " + subject);
               }
               Date sent = message.getSentDate();
               if (sent != null) {
                  System.out.println("Sent: " + sent);
               }

               System.out.print("Do you want to reply [y/n] : ");
               String ans = reader.readLine();
               if ("Y".equals(ans) || "y".equals(ans)) {

                  Message replyMessage = new MimeMessage(session);
                  replyMessage = (MimeMessage) message.reply(false);
                  replyMessage.setFrom(new InternetAddress(to));
                  replyMessage.setText("Thanks");
                  replyMessage.setReplyTo(message.getReplyTo());

                  // Send the message by authenticating the SMTP server
                  // Create a Transport instance and call the sendMessage
                  Transport t = session.getTransport("smtp");
                  try {
	   	     //connect to the smpt server using transport instance
		     //change the user and password accordingly
	             t.connect("abc", "****");
	             t.sendMessage(replyMessage,
                        replyMessage.getAllRecipients());
                  } finally {
                     t.close();
                  }
                  System.out.println("message replied successfully ....");

                  // close the store and folder objects
                  folder.close(false);
                  store.close();

               } else if ("n".equals(ans)) {
                  break;
               }
            }//end of for loop

         } else {
            System.out.println("There is no msg....");
         }

      } catch (Exception e) {
         e.printStackTrace();
      }

   }

}

Compile and Run

现在我们的类已经准备好了,让我们编译上述类。我已经将类 ReplyToEmail.java 保存到目录: /home/manisha/JavaMailAPIExercise 。我们需要类路径中的 jars javax.mail.jar 和 activation.jar。从命令提示符执行以下命令来编译类(两个 jars 都放在 /home/manisha/ 目录中):

javac -cp /home/manisha/activation.jar:/home/manisha/javax.mail.jar: ReplyToEmail.java

现在编译类后,执行以下命令来运行:

java -cp /home/manisha/activation.jar:/home/manisha/javax.mail.jar: ReplyToEmail

Verify Output

您应该在命令控制台上看到以下消息:

From: ABC <abc@gmail.com>
Reply-to: abc@trioteksolutions.com
To: XYZ <xyz@gmail.com>
Subject: Hi today is a nice day
Sent: Thu Oct 17 15:58:37 IST 2013
Do you want to reply [y/n] : y
message replied successfully ....

查看邮件已发送到的收件箱。在我们的案例中,接收到的消息如下所示:

replymessage