java 中上传附件之后有数据没附件

本文将介绍带附件的邮件发送，因为在上文中较详细的说明了一些关键代码作用；
在此就不重复，对代码略作简化，只说明附件部分的代码。

下面直接上代码：

package com.company;

import javax.activation.DataHandler;
import javax.activation.FileDataSource;
import javax.mail.*;
import javax.mail.internet.*;
import java.util.Date;
import java.util.Properties;

/**
 * Created by lining on 2018/5/26.
 */
public class AttachMessageSender {

    private static final String nickname = "李宁";
    private static final String username = "152****[e-mail]";
    private static final String password = "******";
    private static final String protocol = "smtp";
    private static final String host = "smtp.163.com";
    private static final String port = "25";

    public static void main(String[] args) {

        String to = "******[e-mail];******[e-mail]";
        String subject = "文本邮件主题";
        String body = "文本邮件内容";
        String attach = "D:\\TXT\\CMD命令.txt;D:\\TXT\\常用MYSQL语句.txt";

        Email email = new Email();
        email.setToEmails(to.split(";"));
        email.setSubject(subject);
        email.setContent(body);
        email.setAttachments(attach.split(";"));

        if (sendEmail(email)) {
            System.out.println("邮件发送成功!");
        } else {
            System.out.println("邮件发送失败!请及时解决！");
        }
    }

    /**
     * 发送邮件
     * @param email 邮件信息实体
     * @return 是否发送成功 TRUE 发送成功 FALSE 发送失败
     */
    public static boolean sendEmail(Email email) {
        try {

            // 创建Session实例对象
            Session session = createSession();

            // 创建MimeMessage实例对象
            MimeMessage message =createMessage(session, email);

            // 发送邮件
            System.out.println("发送邮件中......");
            Transport.send(message);

            return true;
        } catch (Exception e) {
            System.out.println("发送邮件异常==》");
            e.printStackTrace();
            return false;
        } finally {
            System.out.println("邮件发送结束...");
        }
    }

    /**
     * 创建与邮件服务器的会话对象
     * @return 服务器的会话对象
     */
    public static Session createSession() {
        // 封装属性参数
        Properties props = new Properties();
        props.setProperty("mail.transport.protocol", protocol);
        props.setProperty("mail.smtp.host", host);
        props.setProperty("mail.smtp.port", port);
        props.setProperty("mail.smtp.auth", "true"); // 是否需要验证设置为TRUE，使用授权码发送邮件需要验证

        // 获取与服务器的会话Session对象
        Session session = Session.getInstance(props, new Authenticator() {
            @Override
            protected PasswordAuthentication getPasswordAuthentication() {
                // 登陆账号及密码，密码需要是第三方授权码
                return new PasswordAuthentication(username, password);
            }
        });

        return session;
    }

    /**
     * 创建邮件的核心内容
     * @param session 与服务器交互的会话对象
     * @param email 邮件实体
     * @return 生成的MimeMessage实例对象
     * @throws Exception
     */
    public static MimeMessage createMessage(Session session, Email email) throws Exception{
        // 创建MimeMessage实例对象：表示一整封邮件
        MimeMessage message = new MimeMessage(session);

        // 设置发件人
        if (!nickname.isEmpty()) {
            // 自定义发件人昵称
            message.setFrom(new InternetAddress(MimeUtility.encodeText(nickname) + " <" + username + ">"));
        } else {
            message.setFrom(new InternetAddress(username));
        }

        // 设置收件人
        String[] toEmails = email.getToEmails();
        if (toEmails != null && toEmails.length != 0) {
            InternetAddress[] internetAddressTO = new InternetAddress[toEmails.length];
            for (int i = 0; i < toEmails.length; i++) {
                internetAddressTO[i] = new InternetAddress(toEmails[i]);
            }
            message.setRecipients(Message.RecipientType.TO, internetAddressTO);
        }

        // 设置密送人
        String[] bccEmails = email.getBccEmails();
        if (bccEmails != null && bccEmails.length != 0) {
            InternetAddress[] internetAddressBCC = new InternetAddress[bccEmails.length];
            for (int i = 0; i < bccEmails.length; i++) {
                internetAddressBCC[i] = new InternetAddress(bccEmails[i]);
            }
            message.setRecipients(Message.RecipientType.BCC, internetAddressBCC);
        }

        // 设置抄送人
        String[] ccEmails = email.getCcEmails();
        if (ccEmails != null && ccEmails.length != 0) {
            InternetAddress[] internetAddressCC = new InternetAddress[ccEmails.length];
            for (int i = 0; i < ccEmails.length; i++) {
                internetAddressCC[i] = new InternetAddress(ccEmails[i]);
            }
            message.setRecipients(Message.RecipientType.CC, internetAddressCC);
        }

        // 设置发生日期
        message.setSentDate(new Date());

        // 设置邮件主题
        message.setSubject(email.getSubject());

        /* 创建用于组合邮件正文和附件的MimeMultipart对象 */
        // MimeMultipart类表示一个由多个MIME消息组合成的消息
        MimeMultipart multipart = new MimeMultipart();

        // 设置文本内容
        // MimeBodyPart类表示一个MIME消息
        MimeBodyPart textContent = new MimeBodyPart();
        textContent.setText(email.getContent());
        multipart.addBodyPart(textContent);

        // 设置附件
        String[] attachments = email.getAttachments();
        if (attachments != null && attachments.length != 0) {
            for (String filename: attachments) {
                MimeBodyPart attachPart = createAttachment(filename);
                multipart.addBodyPart(attachPart);
            }
        }

        // 将组合的MimeMultipart对象设置为整个邮件的内容，要注意调用saveChanges方法进行更新
        message.setContent(multipart);

        // 保存并生成最终的邮件内容
        message.saveChanges();

        return message;
    }

    /**
     * 创建邮件中的附件
     * @param filepath 附件的路径
     * @return 生成的附件对象
     * @throws Exception
     */
    public static MimeBodyPart createAttachment(String filepath) throws Exception {
        /* 创建一个表示附件的MimeBodyPart对象，并加入附件内容以及相应的信息 */
        MimeBodyPart attachPart = new MimeBodyPart();

        // FileDataSource用于读取文件数据，并返回代表数据的输入输出流和数据的MIME类型
        FileDataSource fileDataSource = new FileDataSource(filepath);

        // DataHandler类用于封装FileDataSource对象，并为应用程序提供访问数据的接口
        attachPart.setDataHandler(new DataHandler(fileDataSource));

        // 设置附件名称,MimeUtility.encodeText可以处理乱码问题
        attachPart.setFileName(MimeUtility.encodeText(fileDataSource.getName()));

        return attachPart;
    }
}

发送结果