Java邮件发送中附件处理的完整实现教程

import javax.mail.*;
import javax.mail.internet.*;
import javax.activation.*;
import java.io.File;
import java.util.Properties;

public class EmailSenderWithAttachment {

    public static void main(String[] args) {
        // 邮件服务器配置
        String host = "smtp.example.com"; // 替换为你的SMTP服务器
        String username = "your_email@example.com"; // 替换为你的邮箱地址
        String password = "your_email_password"; // 替换为你的邮箱密码
        int port = 587; // 或 465 (SSL)

        Properties props = new Properties();
        props.put("mail.smtp.auth", "true");
        props.put("mail.smtp.starttls.enable", "true"); // 对于587端口
        props.put("mail.smtp.host", host);
        props.put("mail.smtp.port", String.valueOf(port));
        // 如果是SSL，使用465端口，并添加以下配置
        // props.put("mail.smtp.socketFactory.port", "465");
        // props.put("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");

        Session session = Session.getInstance(props, new Authenticator() {
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication(username, password);
            }
        });

        try {
            // 创建MimeMessage对象
            MimeMessage message = new MimeMessage(session);
            message.setFrom(new InternetAddress(username));
            message.setRecipients(Message.RecipientType.TO, InternetAddress.parse("recipient@example.com")); // 替换为收件人邮箱
            message.setSubject("JavaMail测试邮件 - 带附件");

            // 创建一个MimeMultipart对象，用于组合邮件的各个部分（文本和附件）
            MimeMultipart multipart = new MimeMultipart();

            // 1. 添加邮件正文
            MimeBodyPart textPart = new MimeBodyPart();
            textPart.setText("这是一封来自JavaMail的测试邮件，请查收附件。", "UTF-8", "plain"); // 设置编码和内容类型
            multipart.addBodyPart(textPart);

            // 2. 添加附件
            String filePath = "/path/to/your/file.pdf"; // 替换为你的附件路径
            File attachmentFile = new File(filePath);
            if (attachmentFile.exists()) {
                MimeBodyPart attachmentPart = new MimeBodyPart();
                DataSource source = new FileDataSource(attachmentFile);
                attachmentPart.setDataHandler(new DataHandler(source));
                // 设置附件文件名，尤其注意中文文件名编码
                attachmentPart.setFileName(MimeUtility.encodeText(attachmentFile.getName(), "UTF-8", "B"));
                multipart.addBodyPart(attachmentPart);
            } else {
                System.out.println("附件文件不存在: " + filePath);
            }

            // 将MimeMultipart设置到MimeMessage中
            message.setContent(multipart);

            // 发送邮件
            Transport.send(message);
            System.out.println("邮件发送成功！");

        } catch (MessagingException | java.io.UnsupportedEncodingException e) {
            e.printStackTrace();
            System.out.println("邮件发送失败：" + e.getMessage());
        }
    }
}

// ... (之前的Session和MimeMessage设置)

MimeMultipart multipart = new MimeMultipart();

// 1. 添加邮件正文 (纯文本)
MimeBodyPart textPart = new MimeBodyPart();
textPart.setText("这是一封包含多个附件的邮件。", "UTF-8", "plain");
multipart.addBodyPart(textPart);

// 2. 添加第一个附件
String filePath1 = "/path/to/your/file1.pdf";
File attachmentFile1 = new File(filePath1);
if (attachmentFile1.exists()) {
    MimeBodyPart attachmentPart1 = new MimeBodyPart();
    DataSource source1 = new FileDataSource(attachmentFile1);
    attachmentPart1.setDataHandler(new DataHandler(source1));
    attachmentPart1.setFileName(MimeUtility.encodeText(attachmentFile1.getName(), "UTF-8", "B"));
    multipart.addBodyPart(attachmentPart1);
}

// 3. 添加第二个附件
String filePath2 = "/path/to/your/image.png";
File attachmentFile2 = new File(filePath2);
if (attachmentFile2.exists()) {
    MimeBodyPart attachmentPart2 = new MimeBodyPart();
    DataSource source2 = new FileDataSource(attachmentFile2);
    attachmentPart2.setDataHandler(new DataHandler(source2));
    attachmentPart2.setFileName(MimeUtility.encodeText(attachmentFile2.getName(), "UTF-8", "B"));
    multipart.addBodyPart(attachmentPart2);
}

message.setContent(multipart);
// ... (发送邮件)

// ... (Session和MimeMessage设置)

// 最外层的MimeMultipart，用于混合正文（文本/HTML）和附件
MimeMultipart mixedMultipart = new MimeMultipart("mixed");

// 创建一个MimeMultipart用于正文部分，类型为"alternative"
MimeMultipart bodyMultipart = new MimeMultipart("alternative");

// 1. 添加纯文本正文
MimeBodyPart plainTextPart = new MimeBodyPart();
plainTextPart.setText("这是邮件的纯文本内容，如果您的客户端不支持HTML，将会看到此内容。", "UTF-8", "plain");
bodyMultipart.addBodyPart(plainTextPart);

// 2. 添加HTML正文
MimeBodyPart htmlPart = new MimeBodyPart();
String htmlContent = "<h1>你好，世界！</h1><p>这是一封<b>HTML</b>格式的邮件内容。</p>";
htmlPart.setContent(htmlContent, "text/html; charset=UTF-8");
bodyMultipart.addBodyPart(htmlPart);

// 将正文的multipart添加到外层的mixedMultipart中
MimeBodyPart bodyContainer = new MimeBodyPart();
bodyContainer.setContent(bodyMultipart);
mixedMultipart.addBodyPart(bodyContainer);

// 3. 添加附件（和之前一样）
String filePath = "/path/to/your/document.docx";
File attachmentFile = new File(filePath);
if (attachmentFile.exists()) {
    MimeBodyPart attachmentPart = new MimeBodyPart();
    DataSource source = new FileDataSource(attachmentFile);
    attachmentPart.setDataHandler(new DataHandler(source));
    attachmentPart.setFileName(MimeUtility.encodeText(attachmentFile.getName(), "UTF-8", "B"));
    mixedMultipart.addBodyPart(attachmentPart);
}

message.setContent(mixedMultipart);
// ... (发送邮件)

import javax.mail.util.ByteArrayDataSource; // 注意导入路径

// ... (Session和MimeMessage设置)

MimeMultipart multipart = new MimeMultipart();

// 1. 添加邮件正文
MimeBodyPart textPart = new MimeBodyPart();
textPart.setText("这是一封包含内存数据作为附件的邮件。", "UTF-8", "plain");
multipart.addBodyPart(textPart);

// 2. 将字符串内容作为附件发送
String contentToAttach = "这是我从内存中生成的文本内容，可以作为txt文件发送。";
byte[] contentBytes = contentToAttach.getBytes("UTF-8");

MimeBodyPart memoryAttachmentPart = new MimeBodyPart();
// 注意这里的MIME类型，如果是文本就用text/plain
DataSource memorySource = new ByteArrayDataSource(contentBytes, "text/plain");
memoryAttachmentPart.setDataHandler(new DataHandler(memorySource));
memoryAttachmentPart.setFileName(MimeUtility.encodeText("内存文本.txt", "UTF-8", "B"));
multipart.addBodyPart(memoryAttachmentPart);

message.setContent(multipart);
// ... (发送邮件)

// ... (Session和MimeMessage设置)

// 最外层MimeMultipart，类型为"related"，因为它包含HTML和相关的内联资源
MimeMultipart relatedMultipart = new MimeMultipart("related");

// HTML正文部分
MimeBodyPart htmlPart = new MimeBodyPart();
String htmlContent = "<html><body><h1>欢迎！</h1><p>这是我们的Logo：<img src='cid:companyLogo'></p></body></html>";
htmlPart.setContent(htmlContent, "text/html; charset=UTF-8");
relatedMultipart.addBodyPart(htmlPart);

// 内联图片附件
String imagePath = "/path/to/your/logo.png"; // 替换为你的图片路径
File imageFile = new File(imagePath);
if (imageFile.exists()) {
    MimeBodyPart imagePart = new MimeBodyPart();
    DataSource imageSource = new FileDataSource(imageFile);
    imagePart.setDataHandler(new DataHandler(imageSource));
    imagePart.setHeader("Content-ID", "<companyLogo>"); // 必须有<>
    imagePart.setDisposition(MimeBodyPart.INLINE); // 设置为内联
    // 文件名可以设置，但通常内联图片不显示文件名
    imagePart.setFileName(MimeUtility.encodeText(imageFile.getName(), "UTF-8", "B"));
    relatedMultipart.addBodyPart(imagePart);
}

message.setContent(relatedMultipart);
// ... (发送邮件)