我在从电子邮件中获取所有标头时遇到问题。特别是我无法获得电子邮件标题＆＃34; return-path：＆＃34;。虽然我可以从外部邮件获取此标题，但我无法通过内部邮件获取此标题。
我使用的协议：IMAP4
邮件服务器：Exchange 2010
如果我在Exchange服务器上打开内部电子邮件的电子邮件标题，我可以看到所有标题：
Received: from VDLG-EXCH-01 with Microsoft SMTP Server
Received: from VDLG-EXCH-01
Content-Type: application/ms-tnef; name="winmail.dat"
Content-Transfer-Encoding: binary
From: my@email.com
To: demo <demo@email.com>
Subject: FW: qqqq
Thread-Topic: qqqq
Thread-Index: AdOOCZ2g1WQYWPdLTH/Y8hua
Date: Tue, 16 Jan 2018 17:17:45 +0300
Message-ID: <931CD66D7759036FA@vdlg-exch-01.email.com>
References: <AD03856E3028A600@VDMS-EXCH-01.email.com>
In-Reply-To: <AA8D03856E3028A600@VDMS-EXCH-01.email.com>
Accept-Language: en-US, ru-RU
Content-Language: en-US
X-MS-Has-Attach:
X-MS-Exchange-Organization-SCL: -1
X-MS-TNEF-Correlator: <B36C4F75B55C516EC46FA@vdlg-exch-01.email.com>
MIME-Version: 1.0
X-MS-Exchange-Organization-AuthSource: vdlg-exch-01.email.com
X-MS-Exchange-Organization-AuthAs: Internal
X-MS-Exchange-Organization-AuthMechanism: 04
X-Originating-IP: [187.30.155.37]
Return-Path: my@email.com
然而，每当我试图获得＆＃34;返回路径：＆＃34;通过
javax.mail.Message msgTemplate = source.getMessage(1);
Enumeration<Header> header = msgTemplate.getAllHeaders();
我错过了Return-Path：
Received: from VDLG-EXCH-01 with Microsoft SMTP Server
Received: from VDLG-EXCH-01
From: my@email.com
To: demo <demo@email.com>
Subject: FW: qqqq
Thread-Topic: qqqq
Thread-Index: AdOOCZ2g1WQYWPdLTH/Y8hua
Date: Tue, 16 Jan 2018 17:33:05 +0300
Message-ID: <931CD66D7759036FA@vdlg-exch-01.email.com>
References: <AD03856E3028A600@VDMS-EXCH-01.email.com>
In-Reply-To: <AA8D03856E3028A600@VDMS-EXCH-01.email.com>
Accept-Language: en-US, ru-RU
Content-Language: en-US
X-MS-Exchange-Organization-AuthAs: Internal
X-MS-Exchange-Organization-AuthMechanism: 04
X-MS-Exchange-Organization-AuthSource: vdlg-exch-01.email.com
X-MS-Has-Attach:
X-MS-Exchange-Organization-SCL: -1
X-MS-TNEF-Correlator:
Content-Type: text/html; charset="us-ascii"
我做错了什么？
答案 0 :(得分：1)
你没有做错任何事。从邮件服务器外部收到邮件时，将添加Return-Path标头。如果邮件永远不会离开邮件服务器，则可能不会添加Return-Path标头。