// Set Subject: 头字段
            message.setSubject(MimeUtility.encodeText(mail,MimeUtility.mimeCharset("gb2312"),null));
             设置邮件发送日期
            message.setSentDate(new Date());
             设置邮件发件人名称
            Address address = new InternetAddress(mailTitle,MimeUtility.encodeText(mailTitle,1)"> Set From: 头部头字段
            message.setFrom(address);
             Set To: 头部头字段
            message.addRecipient(Message.RecipientType.TO,1)"> InternetAddress(toMail)); 设置邮件格式
            message.setContent(str,"text/html;charset=gbk");