import javax.mail.*;
import javax.mail.internet.*;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Properties;

public class SendEmailUtil {

    /**服务邮箱账号**/
    public static String serviceEmail = "**服务邮箱账号**";
    /**服务邮箱授权码**/
    public static String password = "**服务邮箱授权码**";
    /**发件人**/
    public static String sender = "系统管理员";
    /**主题**/
    public static String subject = "系统通知";
    /**邮箱类型**/
    private static String mailServerName = "163/qq/...";
    /**系统属性**/
    private Properties properties;
    /** 邮件会话对象**/
    private Session session;
    /** MIME邮件对象**/
    private MimeMessage msg;
    /** Multipart对象,邮件内容,标题,附件等内容均添加到其中后再生成MimeMessage对象**/
    private Multipart multipart;
    /**正文内容对象**/
    private BodyPart bp;
    /**对象实例**/
    private static SendEmailUtil instance = null;

    public SendEmailUtil() {
        properties = System.getProperties();
        properties.put("mail.transport.protocol", "smtp");
        properties.put("mail.smtp.host", "smtp." + mailServerName + ".com");
        properties.put("mail.smtp.port", "25");
        properties.put("mail.smtp.auth", "true");
        // 创建验证器
        Authenticator authenticator = new Authenticator() {
            @Override
            public PasswordAuthentication getPasswordAuthentication() {
                // 密码验证(授权码)
                return new PasswordAuthentication(serviceEmail, password);
            }
        };
        // 建立默认会话
        session = Session.getDefaultInstance(properties);
    }

    public static SendEmailUtil getInstance() {
        if (instance == null) {
            instance = new SendEmailUtil();
        }
        return instance;
    }

    /**
     * 发送邮件
     *
     * @param addressee 收件人邮箱
     * @param text      正文
     * @return
     */
    public boolean sendMail(String addressee, String text) {
        boolean success = true;
        try {
            // 建立信息
            msg = new MimeMessage(session);
            multipart = new MimeMultipart();
            // 自定义发件人昵称
            String nikeName = MimeUtility.encodeText(sender);
            // 设置发件人
            msg.setFrom(new InternetAddress(serviceEmail, nikeName));
            // 设置收件人
            if (addressee != null) {
                InternetAddress[] iaToList = new InternetAddress().parse(addressee);
                msg.setRecipients(Message.RecipientType.TO, iaToList);
            }
            // 设置抄送人
            // InternetAddress[] parse = new InternetAddress().parse(copyto);
            // msg.setRecipients(Message.RecipientType.CC,parse);
            // 设置发送日期
            msg.setSentDate(new Date());
            Date date = new Date();
            SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm");
            String DateSuffix = dateFormat.format(date);
            // 设置主题
            msg.setSubject(subject + DateSuffix);
            // 设置正文
            bp = new MimeBodyPart();
            bp.setText(text);
            multipart.addBodyPart(bp);
            // 获取图片的流
            // URL url = new URL(fileUrl);
            // HttpURLConnection conn = (HttpURLConnection)url.openConnection();
            // conn.setRequestMethod("GET");
            // conn.setConnectTimeout(5 * 1000);
            // InputStream inStream = conn.getInputStream();//通过输入流获取图片数据
            // 设置附件
            // bp = new MimeBodyPart();
            // bp.setDataHandler(new DataHandler(new ByteArrayDataSource(inStream,"application/x-jpg")));
            // String fileName = String.valueOf(System.currentTimeMillis())+ ".jpg";
            // bp.setFileName(MimeUtility.encodeText(fileName, "UTF-8", "B"));
            // multipart.addBodyPart(bp);
            msg.setContent(multipart);
            msg.saveChanges();
            // 邮件服务器进行验证
            Transport tran = session.getTransport("smtp");
            // 配置发送者的邮箱和密码
            tran.connect("smtp." + mailServerName + ".com", serviceEmail, password);
            // 发送
            tran.sendMessage(msg, msg.getAllRecipients());
            // 邮件连接关闭
            tran.close();
            System.out.println("邮件发送成功!收件人："+addressee);
        } catch (Exception e) {
            e.printStackTrace();
            success = false;
        }
        return success;
    }

    public static void main(String[] args) throws InterruptedException {

        SendEmailUtil emailUtil = SendEmailUtil.getInstance();
        while (true) {
            emailUtil.sendMail("**接收邮箱地址**", "this is a testing message , please don`t answer the e-mail.");
        }

    }

}