Java邮件不返回主题 [英] Java mail don't return subject

问题描述

我正在使用javamail营救收件箱中的邮件.我从收件箱中收到所有邮件，但是subject(message.getSubject())返回null.

I'm using javamail to rescue mails of inbox. I get all mails from inbox, but the subject(message.getSubject()) return null.

我在几个地点进行了研究，所有提出的解决方案都行不通.

I research in several sites and all proposed solutions not work.

仅在Tomcat6中会发生此问题，如果我在Java项目中对主要方法执行了偶数代码，则我得到了所有属性，包括主题.我是SSL协议用户(pop3s).

This problem occurs only in the Tomcat6, if a execute even code in java project for main method i get all atributis, include subject. I'm user de SSL protocol (pop3s).

感谢帮助

public void getMails(final String host, final int port, final String user, final String password){

   final Session session = Session.getInstance(System.getProperties(), null);
   final Store store = session.getStore("pop3s");   

   store.connect(host, port, user, password);
   Folder inbox = store.getFolder("INBOX");
   inbox.open(Folder.READ_WRITE);
   int count = inbox.getMessageCount();
   System.out.println(" Count Emails "+count);

   final Message[] messages = inbox.getMessages();                
   for (final Message message : messages) { 
       //This return null
       System.out.print("mail subject: " + message.getSubject() + " send at: " + message.getSentDate());
       //This return body of mail
       System.out.print("mail subject: " + message.getContent().toString());
}

直接在eclipse上我的Main方法的输出:

My output for the method Main directly on eclipse:

MessageCount: 4

全名: INBOX

NewMessageCount: 0

getDescription: null

getFileName: null

getMessageNumber: 1

getSize: 2297

getSentDate::2015年8月3日星期一17:23:10 BRT

getSentDate: Mon Aug 03 17:23:10 BRT 2015

来自: Silvano Wojczak [e-mail]

from: Silvano Wojczak [e-mail]

内容:javax.mail.internet.MimeMultipart@6769ba97

Content: javax.mail.internet.MimeMultipart@6769ba97

内容getClass:类javax.mail.internet.MimeMultipart

Content getClass: class javax.mail.internet.MimeMultipart

对于TomCat6中的log4j:

For log4j in TomCat6:

MessageCount: 4

全名: INBOX

NewMessageCount: 0

getDescription: null

getFileName: null

getMessageNumber: 1

getSize: 6731

getSentDate:空

发件人: null

内容:javax.mail.internet.MimeMultipart@6769ba97

Content: javax.mail.internet.MimeMultipart@6769ba97

内容getClass:类javax.mail.internet.MimeMultipart

Content getClass: class javax.mail.internet.MimeMultipart

推荐答案

在我看来，安装Tomcat 6的运行时具有自己的JavaMail实现.

It seems to me that the runtime of your installation of Tomcat 6 has its own implementation of JavaMail.

您最好先确保实际上使用了 的JavaMail.在错误发生之前，立即在读取邮件的同一程序中执行此剪贴簿:

You'd better ensure first which implementation of JavaMail are you using actually. Execute this scrap in the same program that reads the mail, immediately before the error occurs:

    String packageName="javax.mail.internet.";
    String simpleClassName="MimeMultipart";
    String className=packageName+simpleClassName;
    Class<?> cl=Class.forName(className);
    URL url=cl.getResource(simpleClassName+".class");
    System.out.println("url="+url);

使用较旧的geronimo-mail实现时遇到此类问题，在读取标题之前，我先通过克隆消息来解决了这些问题:

Once I suffered this kind of problems when using older implementations of geronimo-mail, and I got to solved them by cloning the message before reading the headers:

private static MimeMessage cloneMimeMessage(Session session, MimeMessage src)
    throws MessagingException
{
    if (src instanceof POP3Message)
    {
        return new MimeMessage(session, ((POP3Message)src).top(Integer.MAX_VALUE));
    }
    else if (src instanceof IMAPMessage)
    {
        return new MimeMessage(session, ((IMAPMessage)src).getRawInputStream());
    }
    else
    {
        throw new UnsupportedOperationException();
    }
}

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