如何使用 JavaMail API 读取电子邮件附件（当 contentType 为 text/plain 时）

Question

我们有一个外部应用程序，它向我们发送一封带有附件的电子邮件。 在 contentType Multipart 的情况下：我们能够解析和处理附件。

但是有时他们发送带有 contentType text/plain 的邮件（ message.getContent() 为 null），我们无法从消息 obj 中获取附件和电子邮件正文。

发送方无法将内容类型固定为多部分，我们必须在接收方端容纳它。

我们正在使用 JavaMail API 1.5，尝试了 apache commons mail util，但它仅在 message.getContent() 中有对象时才有效

文件夹 emailFolder = store.getFolder("INBOX"); emailFolder.open(Folder.READ_ONLY);

Message[] 消息 = emailFolder.getMessages(); System.out.println("消息总数" + 消息长度);

for (int i = 0; i < messages.length; i++) { Message message = messages[i];

Multipart multipart = (Multipart) message.getContent();
 for(int k = 0; k < multipart.getCount(); k++){
   BodyPart bodyPart = multipart.getBodyPart(k);  
   InputStream stream = 
                     (InputStream) bodyPart.getInputStream();  
 }

}

**RAW MIME message content :**
  From: SENDER <SENDER@MyOrgLtd.com>
To: "'support@XYZ.com'" <'support@XYZ.com'>
Subject: Change Request #CHG85 02 ATTACHMENT
Thread-Topic: Change Request #CHG85 02 ATTACHMENT
Thread-Index: AdVQ+bdv3Fd+yaP6Qr2RCdQvPsvI9Q==
Date: Mon, 12 Aug 2019 10:37:23 +0000
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--_002_1dcdc97a916b4f929414d0d4b6703397DELHIXCHMBX003MyOrgLtd_
Content-Type: text/plain; charset="us-ascii"
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hi User,
    We have received the data, will process and inform you.

Thank you,
admin


--_002_1dcdc97a916b4f929414d0d4b6703397DELHIXCHMBX003MyOrgLtd_
Content-Type: application/octet-stream; name="testData.csv"
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    creation-date="Mon, 12 Aug 2019 10:35:38 GMT";
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Answer 1

如果内容类型为 text/plain，则没有附件。

如果 message.getContent() 返回 null，则可能也没有消息内容，或者消息格式有问题。 发布消息的原始 MIME 内容，我可以帮助您找出消息中的问题。