Java Mail-以字符串形式读取附件 [英] Java Mail - read in the attachment as String
问题描述
我开始使用Java Mail，并且对处理附件有一些疑问:
I am beginning to work with Java Mail and I have a few questions about processing of attachment:
-
如果我们的内容是
Multipart，即具有附件，则实际附件位于哪个索引，在哪个位置可以找到消息内容?我只想只处理附件.
If our content is a
Multiparti.e. has an attachment, at which index is the actual attachment and at which can we find the message content? I simply want to process just attachments.
这是正确的方法吗?如果我想将给定的附件转换为字符串，只需阅读附件部分的流(使用getStream())并将其附加到字符串生成器，然后返回字符串?
Would it be a correct approach. if I wanted to convert a given attachment to a String, to simply read through the stream of the attachment part (using getStream()) and append it to String builder and then return a String?
非常感谢您提供任何建议
Thanks a lot for any advice
推荐答案
1.) 这来自我的一个应用程序(也基于其他人的代码，但我找不到功劳).
1.) This is from one of my applications (also based on someone else's code but i could not find to give credit).
如您所见，我正在递归处理Part对象(首先它实际上是一条消息).
As you can see i'm recursively processing a Part object (first it's actually a Message).
我删除了一些不相关的代码.
I removed some code which is irrelevant.
private BodyPartDOM collectBodyParts(Part part) throws IOException, MessagingException {
BodyPartDOM dom = new BodyPartDOM();
Object content = part.getContent();
if (content instanceof String) {
// process as string
} else if (content instanceof Multipart) {
Multipart innerMultiPart = (Multipart) content;
int count = innerMultiPart.getCount();
for (int i = 0; i < count; i++) {
BodyPart innerBodyPart = innerMultiPart.getBodyPart(i);
BodyPartDOM subDom = collectBodyParts(innerBodyPart);
// further recursive processing
}
} else if (content instanceof InputStream) {
// process inputStream
}
return dom;
}
2.)如果将其转换为String，请继续.但是请注意文件流.
2.) If you convert it to a String go ahead. But watch out for file streams for example.
您可以检查mime类型的内容类型.以下是维基百科提供的一些信息，它们将对您有所帮助(http://en.wikipedia.org/wiki/MIME#Content-Type):
You can check the mime type for the content type. Here are some infor from wikipedia that will help (http://en.wikipedia.org/wiki/MIME#Content-Type):
Content-Type此标头指示 消息内容，例如，由类型和子类型组成
Content-Type This header indicates the Internet media type of the message content, consisting of a type and subtype, for example
Content-Type:文本/纯文本通过使用多部分类型MIME 允许邮件的各个部分以树状结构排列，其中 叶节点是任何非多部分内容类型，非叶节点 是多种多部分类型中的任何一种.该机制支持:
Content-Type: text/plain Through the use of the multipart type, MIME allows messages to have parts arranged in a tree structure where the leaf nodes are any non-multipart content type and the non-leaf nodes are any of a variety of multipart types. This mechanism supports:
使用文本/纯文本的简单文本消息(默认值 内容类型:")文本以及附件(多部分/与 文字/纯文字部分和其他非文字部分).包含以下内容的MIME消息: 附加文件通常用指示文件的原始名称. 标头为"Content-disposition:"，因此文件类型均显示为 通过MIME内容类型和(通常是特定于操作系统的)文件名 带原始附件的扩展名回复(多部分/与 文本/纯文本部分，原始消息作为message/rfc822部分) 替代内容，例如以纯文本和 另一种格式，例如HTML(相同的多部分/替代格式 文本/纯文本和文本/html形式的内容)图像，音频，视频和 应用程序(例如，图像/jpeg，音频/mp3，视频/mp4和 应用程序/msword等)许多其他消息构造
simple text messages using text/plain (the default value for "Content-Type: ") text plus attachments (multipart/mixed with a text/plain part and other non-text parts). A MIME message including an attached file generally indicates the file's original name with the "Content-disposition:" header, so the type of file is indicated both by the MIME content-type and the (usually OS-specific) filename extension reply with original attached (multipart/mixed with a text/plain part and the original message as a message/rfc822 part) alternative content, such as a message sent in both plain text and another format such as HTML (multipart/alternative with the same content in text/plain and text/html forms) image, audio, video and application (for example, image/jpeg, audio/mp3, video/mp4, and application/msword and so on) many other message constructs
如何将其付诸实践可以在这里找到: http://www.oracle.com/technetwork/java/faq-135477.html
How to put that into practice can be found here: http://www.oracle.com/technetwork/java/faq-135477.html
祝您编程愉快！
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