在电子邮件中发送内联图片（Send inline image in email）

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2023-12-01

以下是使用内嵌图像从您的计算机发送HTML电子邮件的示例。在这里，我们使用了JangoSMPT服务器，通过该服务器将电子邮件发送到我们的目标电子邮件地址。环境设置章节中介绍了该设置。

要发送包含内嵌图像的电子邮件，请执行以下步骤:

参加一个会议
创建一个默认的MimeMessage对象，并在消息中设置From, To, Subject 。
创建一个MimeMultipart对象。

在我们的示例中，我们将在电子邮件中包含HTML部分和图像。首先创建HTML内容并将其设置在multipart对象中:

// first part (the html)
BodyPart messageBodyPart = new MimeBodyPart();
String htmlText = "<H1>Hello</H1><img src=\"cid:image\">";
messageBodyPart.setContent(htmlText, "text/html");
// add it
multipart.addBodyPart(messageBodyPart);

接下来，通过创建Datahandler来添加图像，如下所示:

// second part (the image)
messageBodyPart = new MimeBodyPart();
DataSource fds = new FileDataSource(
 "/home/manisha/javamail-mini-logo.png");
messageBodyPart.setDataHandler(new DataHandler(fds));
messageBodyPart.setHeader("Content-ID", "<image>");

接下来在消息中设置multipart，如下所示:
```
message.setContent(multipart);
```
使用Transport对象发送消息。

创建Java类 (Create Java Class)

创建一个java类文件SendInlineImagesInEmail ，其内容如下:

package cn.xnip;
import java.util.Properties;
import javax.activation.DataHandler;
import javax.activation.DataSource;
import javax.activation.FileDataSource;
import javax.mail.BodyPart;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;
public class SendInlineImagesInEmail {
   public static void main(String[] args) {
      // Recipient's email ID needs to be mentioned.
      String to = "destinationemail@gmail.com";
      // Sender's email ID needs to be mentioned
      String from = "fromemail@gmail.com";
      final String username = "manishaspatil";//change accordingly
      final String password = "******";//change accordingly
      // Assuming you are sending email through relay.jangosmtp.net
      String host = "relay.jangosmtp.net";
      Properties props = new Properties();
      props.put("mail.smtp.auth", "true");
      props.put("mail.smtp.starttls.enable", "true");
      props.put("mail.smtp.host", host);
      props.put("mail.smtp.port", "25");
      Session session = Session.getInstance(props,
         new javax.mail.Authenticator() {
            protected PasswordAuthentication getPasswordAuthentication() {
               return new PasswordAuthentication(username, password);
            }
         });
      try {
         // Create a default MimeMessage object.
         Message message = new MimeMessage(session);
         // Set From: header field of the header.
         message.setFrom(new InternetAddress(from));
         // Set To: header field of the header.
         message.setRecipients(Message.RecipientType.TO,
            InternetAddress.parse(to));
         // Set Subject: header field
         message.setSubject("Testing Subject");
         // This mail has 2 part, the BODY and the embedded image
         MimeMultipart multipart = new MimeMultipart("related");
         // first part (the html)
         BodyPart messageBodyPart = new MimeBodyPart();
         String htmlText = "<H1>Hello</H1><img src=\"cid:image\">";
         messageBodyPart.setContent(htmlText, "text/html");
         // add it
         multipart.addBodyPart(messageBodyPart);
         // second part (the image)
         messageBodyPart = new MimeBodyPart();
         DataSource fds = new FileDataSource(
            "/home/manisha/javamail-mini-logo.png");
         messageBodyPart.setDataHandler(new DataHandler(fds));
         messageBodyPart.setHeader("Content-ID", "<image>");
         // add image to the multipart
         multipart.addBodyPart(messageBodyPart);
         // put everything together
         message.setContent(multipart);
         // Send message
         Transport.send(message);
         System.out.println("Sent message successfully....");
      } catch (MessagingException e) {
         throw new RuntimeException(e);
      }
   }
}

由于我们使用主机提供商JangoSMTP提供的SMTP服务器，我们需要验证用户名和密码。 javax.mail.PasswordAuthentication类用于验证密码。

编译和运行 (Compile and Run)

现在我们的课已经准备好了，让我们编译上面的类。我已将类SendInlineImagesInEmail.java保存到目录: /home/manisha/JavaMailAPIExercise 。我们需要在类路径中使用jars 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: SendInlineImagesInEmail.java

现在编译了类，执行以下命令来运行:

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

验证输出 (Verify Output)

您应该在命令控制台上看到以下消息:

Sent message successfully....

当我通过JangoSMTP向我的Gmail地址发送电子邮件时，我的gmail帐户收件箱中会收到以下邮件: