python邮件发送给多人时，只有第一个人能收到的问题

我也是被坑了好久才发现。

解决方法：

经过多次测试发现MIMEText()["to"]的数据类型与sendmail(from_addrs,to_addrs,...)的to_addrs不同；

前者为str类型，多个地址使用逗号分隔，后者为list类型。

原本有问题的代码：

def send_mail_attach(receivers, mail_subject, mail_body, pattern="html"):
    import smtplib
    from email.mime.text import MIMEText
    # 设置服务器所需信息
    # 163邮箱服务器地址
    mail_host = 'hwhzsmtp.qiye.163.com'
    # 163用户名
    mail_user = 'wang123@xxx.one'
    # 密码(部分邮箱为授权码)
    mail_pass = '1234567'
    # 邮件发送方邮箱地址
    sender = 'wang123@xxx.one'
    # 邮件接受方邮箱地址，注意需要[]包裹，这意味着你可以写多个邮件地址群发

    # 设置email信息
    # 邮件内容设置
    message = MIMEText(mail_body, pattern, 'utf-8')
    # 邮件主题
    message['Subject'] = mail_subject
    # 发送方信息
    message['From'] = '%s <%s>' % (Header('hours report').encode(), sender)
    # 接受方信息
    if not isinstance(receivers,list):
        receivers=[receivers]
    message['To'] = ','.join(receivers)
    # 登录并发送邮件
    try:

        # smtpObj = smtplib.SMTP(mail_host,25)
        smtpObj = smtplib.SMTP_SSL(mail_host, 994)
        # 连接到服务器
        # smtpObj.starttls()
        # smtpObj.ehlo()

        # 登录到服务器
        smtpObj.login(mail_user, mail_pass)
        # 发送
        smtpObj.sendmail(
            sender, receivers, message.as_string())
        # 退出
        smtpObj.quit()
        print('success')
    except smtplib.SMTPException as e:
        print('error', e)  # 打印错误

经过修改之后的代码如下：

def send_email(mail_subject, mail_body, receivers='wqbin@xxx.one', pattern='plain'):
    # 设置服务器所需信息
    # 163邮箱服务器地址

    mail_host = 'hwhzsmtp.qiye.163.com'
    # 163用户名
    mail_user = 'wang123@xxx.one'
    # 密码(部分邮箱为授权码)
    mail_pass = '123456'
    # 邮件发送方邮箱地址
    sender = 'wang123@xxx.one'
    # 邮件接受方邮箱地址，注意需要[]包裹，这意味着你可以写多个邮件地址群发

    # 设置email信息
    # 邮件内容设置
    message = MIMEText(mail_body, pattern, 'utf-8')
    # 邮件主题
    message['Subject'] = mail_subject
    # 发送方信息
    message['From'] = '%s' %  sender
    # 接受方信息
    # 此处只能填写''',+str'''
    message['To'] = ','.join(receivers) if isinstance(receivers,list) else receivers

    # 登录并发送邮件
    try:

        # smtpObj = smtplib.SMTP(mail_host,25)
        smtpObj = smtplib.SMTP_SSL(mail_host, 994)
        # 连接到服务器
        # smtpObj.starttls()
        # smtpObj.ehlo()

        # 登录到服务器
        smtpObj.login(mail_user, mail_pass)
        # 发送
        # 此处填写 list格式
        if not isinstance(receivers,list):
            receivers=receivers.split(",")
        smtpObj.sendmail(
            sender, receivers, message.as_string())
        # 退出
        smtpObj.quit()
        print('success')
    except smtplib.SMTPException as e:
        print('error', e)  # 打印错误
    except Exception as e:
        print('其他错误',e)

完结！！