如何通过 javax.mail 使用 SMTP 从 Android 发送电子邮件

Question

我正在制作一个具有通过 SMTP 协议从应用程序发送电子邮件的功能的应用程序。我想让它在后台从应用程序发送电子邮件，而不是像使用其他邮件应用程序发送 Intent 一样。我在 Google 上搜索了一些与 javax.mail 有关的建议。

我有 SMTP 服务器，其中包含以下信息：主机、端口、用户名、密码。

如何使用 javax.mail 通过 SMTP 发送电子邮件，其中包含 html 到 recipient/recipients，并且电子邮件也有附件。

谢谢

Answer 1

如果您想使用javax.mail发送电子邮件。您可以使用以下助手 class 发送电子邮件。不管它是由后台服务发送的还是由 AsyncTask 发送的。看看下面class中的配置部分。

package com.company.mail.util;

import java.util.Properties;

import javax.activation.DataHandler;
import javax.mail.Message;
import javax.mail.Multipart;
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;

import org.apache.commons.lang.ArrayUtils;
import org.apache.commons.lang.StringUtils;

public class Mail {
    public static final String EMAIL_LIST_SEPARATOR = ",";

    public boolean sendMail(String[] toEmails, String subject, String msg, boolean isHTML, String charSet, String filename, byte[] attachment) {
    if (toEmails == null || (toEmails != null && toEmails.length == 0))  return false;

    String name = "My Company Name";
    String username = "no-reply@company.com"; 
    String password = "<My Password>"; 
    String host = "smtp.company.com";
    Integer port = 465;
    String from = "no-reply@company.com";

    Properties props = new Properties();
    props.put("mail.smtp.host", host);
    props.put("mail.smtp.socketFactory.port", port.toString());
    props.put("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
    props.put("mail.smtp.auth", "true");
    props.put("mail.smtp.port", port.toString());

    final String fUsername = username;
    final String fPassword = password;
    Session mailSession = Session.getDefaultInstance(props, new javax.mail.Authenticator() {
        protected PasswordAuthentication getPasswordAuthentication() {
            return new PasswordAuthentication(fUsername, fPassword);
        }
    });
    //mailSession.setDebug(true);

    String recipients = ArrayUtils.toString(toEmails, "");
    Message message = new MimeMessage(mailSession);
    try {
        message.setFrom(new InternetAddress(from, name));
        message.setReplyTo(new InternetAddress[] { new InternetAddress(from, name) });
        message.setSubject(subject);
        message.setContent(msg, isHTML ? "text/html" : "text/plain");

        if (toEmails != null) {
            for (String recipient : toEmails) {
                if (recipient != null && !"".equals(recipient)) {
                    message.addRecipient(Message.RecipientType.TO, new InternetAddress(recipient));
                }
            }

            if (attachment != null) {
                MimeBodyPart messagePart = new MimeBodyPart();
                if (isHTML)
                    messagePart.setContent(msg, "text/html");
                else
                    messagePart.setText(msg);

                MimeBodyPart attachmentPart = new MimeBodyPart();
                attachmentPart.setDataHandler(new DataHandler(attachment, "application/octet-stream"));
                attachmentPart.setFileName(filename);

                Multipart multipart = new MimeMultipart();
                multipart.addBodyPart(messagePart);
                multipart.addBodyPart(attachmentPart);

                message.setContent(multipart);
            }

            Transport.send(message);
            Log.i(" [Mail] Recipient " + name + " <" + username + "> sent e-mail with subject " + subject + " to recipient(s): " + recipients);

            return true;
        }
    } catch (Exception e) {
        Log.e(" [Mail] Error sending " + toEmails.length  + " e-mail(s) with subject '" + subject + "' to recipient(s) (" + recipients + "): " + e.getMessage());
    }

    return false;
    }
}

您可以调用方法mail.sendMail(...)发送邮件，例如：

Mail mail = new Mail();
mail.sendMail(new String[] { "someone@somewhere.com", "john.doe@mycompany.com" }, "Subject of my e-mail", "This is a message in <b>HTML</b> with <i>italics</i>.", true, "UTF-8", null, null);

此 class 还支持向邮件发送附件，因此您可以将文件名和字节数组作为最后两个参数传递。

希望这篇Javaclass对您有所帮助。

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