第一步：添加依赖:
<dependency>
       <groupId>javax.mail</groupId>
            <artifactId>mail</artifactId>
            <version>1.4</version> 
</dependency>

第二步：复制粘贴、运行:
/*
    * 发送邮件 (阿里云邮箱企业版)
    * @param fromEmail
    *            发送邮箱
    * @param toEmail
    *            接收邮箱
    * @param emailName
    *            阿里云邮箱登录名
    * @param emailPassword
    *            密码
    * @param title
    *            发送主题
    * @param centent
    *            发送内容
    * @throws Exception
    */

    public static void sendMail(String fromEmail, String toEmail, String emailName, String emailPassword, String title,String centent) throws Exception{
      
        Properties prop=new Properties();
        prop.put("mail.host","smtp.mxhichina.com" );
        prop.put("mail.transport.protocol", "smtp");
        prop.put("mail.smtp.auth", "true");
        Session session=Session.getInstance(prop);
        session.setDebug(true);
        Transport ts=session.getTransport();
        ts.connect(emailName, emailPassword);
        Message message=new MimeMessage(session);
        message.setFrom(new InternetAddress(fromEmail));
        message.setRecipient(Message.RecipientType.TO, new InternetAddress(toEmail));
        message.setSubject(title);
        message.setContent(centent, "text/html;charset=utf-8");  
        ts.sendMessage(message, message.getAllRecipients());
    }