通过Gmail API发送带有纯文本后备格式的HTML电子邮件

通过Gmail API发送带有纯文本后备格式的HTML电子邮件

要提供两种选择，您可以将设置为

Content-Type

，

mixed/alternative

而不是

text/plain

或

text/html

：

如果我们想尝试了这一点，在API
Explorer中
，我们只是使用base64编码的邮件，并使其安全网址，所有替换

/

与

_

和所有

+

与

-

。

在开发者控制台中：

btoa(  "Subject: Example Subjectrn" +  "From: <[email protected]>rn" +  "To: <[email protected]>rn" +  "Content-Type: multipart/alternative; boundary="foo_bar"rnrn" +  "--foo_barrn" +  "Content-Type: text/plain; charset=UTF-8rnrn" +  "*Bold example message text*rnrn" +  "--foo_barrn" +  "Content-Type: text/html; charset=UTF-8rnrn" +  "<div dir="ltr"><b>Bold example message text</b></div>rnrn" +  "--foo_bar--" ).replace(/+/g, '-').replace(///g, '_');POST https://www.googleapis.com/gmail/v1/users/me/messages/send?access_token={YOUR_API_KEY}{ "raw": "U3ViamVjdDogRXhhbXBsZSBTdWJqZWN0DQpGcm9tOiA8ZXhhbXBsZUBnbWFpbC5jb20-DQpUbzogPGV4YW1wbGVAZ21haWwuY29tPg0KQ29udGVudC1UeXBlOiBtdWx0aXBhcnQvYWx0ZXJuYXRpdmU7IGJvdW5kYXJ5PSJmb29fYmFyIg0KDQotLWZvb19iYXINCkNvbnRlbnQtVHlwZTogdGV4dC9wbGFpbjsgY2hhcnNldD1VVEYtOA0KDQoqQm9sZCBleGFtcGxlIG1lc3NhZ2UgdGV4dCoNCg0KLS1mb29fYmFyDQpDb250ZW50LVR5cGU6IHRleHQvaHRtbDsgY2hhcnNldD1VVEYtOA0KDQo8ZGl2IGRpcj0ibHRyIj48Yj5Cb2xkIGV4YW1wbGUgbWVzc2FnZSB0ZXh0PC9iPjwvZGl2Pg0KDQotLWZvb19iYXItLQ=="}

要在Java中执行等效 *** 作，您可以执行以下 *** 作：

Message message = new MimeMessage(session);Multipart multiPart = new MimeMultipart("alternative");MimeBodyPart textPart = new MimeBodyPart();textPart.setText(text, "utf-8");MimeBodyPart htmlPart = new MimeBodyPart();htmlPart.setContent(html, "text/html; charset=utf-8");multiPart.addBodyPart(textPart); multiPart.addBodyPart(htmlPart);message.setContent(multiPart);ByteArrayOutputStream output = new ByteArrayOutputStream();message.writeTo(output);String rawEmail = base64.enprebase64URLSafeString(output.toByteArray());Message message = new Message();message.setRaw(rawEmail);message = service.users().messages().send(userId, message).execute();