类名

import java.io.File;
import java.io.InputStream;
import java.util.List;
import java.util.Properties;
import java.util.ResourceBundle;

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.Multipart;
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 javax.mail.internet.MimeUtility;


public class EmailUtil {

    private MimeMessage message;
    private Session session;
    private Transport transport;

    private String mailHost = "";
    private String sender_username = "";
    private String sender_password = "";

	private final static ResourceBundle rb = ResourceBundle.getBundle("config/config");

    /*
     * 初始化方法
     */
    public EmailUtil() {
        InputStream in = EmailUtil.class.getResourceAsStream("MailServer.properties");
        this.mailHost = rb.getString("mail_host");
		this.sender_username = rb.getString("mail_from");
		this.sender_password = rb.getString("mail_password");

        Properties props = new Properties();
		// Setup mail server
		props.put("mail.smtp.host", mailHost);// 设置smtp主机
		props.put("mail.smtp.auth", "true");// 使用smtp身份验证
		// Get session
		session = Session.getDefaultInstance(props, null);
        message = new MimeMessage(session);
    }

    /**
     * 发送邮件
     *
     * @param subject
     *            邮件主题
     * @param sendHtml
     *            邮件内容
     * @param receiveUser
     *            收件人地址
     * @param attachment
     *            附件
     */
    public void doSendHtmlEmail(String subject, String sendHtml, String receiveUser, File attachment, List<String> bccUserList) {
        try {
            // 发件人
            InternetAddress from = new InternetAddress(sender_username);
            message.setFrom(from);

            // 收件人
            InternetAddress to = new InternetAddress(receiveUser);
            if(bccUserList !=null && bccUserList.size() > 0){
	            InternetAddress[] cc =new InternetAddress[bccUserList.size()];
	            for(int i=0;i<bccUserList.size() ; i++){
	            	cc[i] = new InternetAddress( bccUserList.get(i));
	            }
	            message.setRecipients(Message.RecipientType.CC,cc);
            }
            message.setRecipient(Message.RecipientType.TO, to);


            message.setRecipient(Message.RecipientType.BCC, bcc);*/
            // 邮件主题
            message.setSubject(subject);

            // 向multipart对象中添加邮件的各个部分内容，包括文本内容和附件
            Multipart multipart = new MimeMultipart();

            // 添加邮件正文
            BodyPart contentPart = new MimeBodyPart();
            contentPart.setContent(sendHtml, "text/html;charset=UTF-8");
            multipart.addBodyPart(contentPart);

            // 添加附件的内容
            if (attachment != null) {
                BodyPart attachmentBodyPart = new MimeBodyPart();
                DataSource source = new FileDataSource(attachment);
                attachmentBodyPart.setDataHandler(new DataHandler(source));

                // 网上流传的解决文件名乱码的方法，其实用MimeUtility.encodeWord就可以很方便的搞定
                // 这里很重要，通过下面的Base64编码的转换可以保证你的中文附件标题名在发送时不会变成乱码
                //sun.misc.BASE64Encoder enc = new sun.misc.BASE64Encoder();
                //messageBodyPart.setFileName("=?GBK?B?" + enc.encode(attachment.getName().getBytes()) + "?=");

                //MimeUtility.encodeWord可以避免文件名乱码
                attachmentBodyPart.setFileName(MimeUtility.encodeWord(attachment.getName()));
                multipart.addBodyPart(attachmentBodyPart);
            }

            // 将multipart对象放到message中
            message.setContent(multipart);
            // 保存邮件
            message.saveChanges();

            transport = session.getTransport("smtp");
            // smtp验证，就是你用来发邮件的邮箱用户名密码
            transport.connect(mailHost, sender_username, sender_password);
            // 发送
            transport.sendMessage(message, message.getAllRecipients());

            System.out.println("send success!");
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (transport != null) {
                try {
                    transport.close();
                } catch (MessagingException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    public static void main(String[] args) {
    	EmailUtil emailUtil = new EmailUtil();
		String subject = "www.javaweb.top";
		String context = "亲爱的用户：<br>&nbsp;&nbsp;&nbsp;&nbsp;您好！验证码为：";
		emailUtil.doSendHtmlEmail(subject, context, "742275749@qq.com", null, null);
    }
}

配置config

#email config
mail_host=
mail_from=
mail_password=
mail_username=
mail_bcc=