使用 javamail API 阅读邮件时出现阿拉伯语内容问题

Question

我正在使用 Javamail API 从 Gmail 服务器读取邮件。我正在将一封包含阿拉伯语内容的邮件从一个 Gmail ID 发送到另一个 Gmail ID。邮件的字符集编码类型是windows-1256。当我使用 Javamail 下载邮件时，我收到“??????”中的内容 格式而不是阿拉伯字符。我正在将下载的内容转换为 UTF-8 格式，但仍然无法正确显示。

提前致谢，

蒂姆

更新：
我使用以下代码来获取内容：

Object content = message.getContent(); 
if (message.isMimeType("text/html")  
      || message.isMimeType("text/plain")) { 
      Al = (String) content; 
} 

下载内容后，将使用以下代码进行 UTF-8 编码：

byte[] utf8Bytes = s.getBytes("UTF-8"); 
s = new String(utf8Bytes, "UTF-8"); 

更新：我目前用于阅读邮件内容的完整代码

String gmailMultipartMailDownload(Multipart multipart, String Uids)
        throws SocketException, UnsupportedDataTypeException, UnsupportedEncodingException {
    String Content = new String("");        
    try {
        int numParts = multipart.getCount();            
        for (int k = 0; k < numParts; k++)
        {
            BodyPart bodyPart = multipart.getBodyPart(k);
            Object tmp = null;
            try 
            {
                tmp = bodyPart.getContent();
            } 
            catch (UnsupportedDataTypeException UEE)
            {
                try {
                    InputStream is = bodyPart.getInputStream();
                    BufferedReader br = new BufferedReader(new InputStreamReader(is));
                    StringBuilder sb = new StringBuilder();
                    String line = null;

                    while ((line = br.readLine()) != null)
                    {
                        sb.append(line + "\n");
                    }

                    br.close();
                    return sb.toString();
                } catch (IOException e) {
                    e.printStackTrace();
                } catch (MessagingException e) {                        
                    e.printStackTrace();
                }
            } catch (UnsupportedEncodingException UEE) {
                UEE.printStackTrace();
                try {
                    InputStream is = bodyPart.getInputStream();
                    BufferedReader br = new BufferedReader(new InputStreamReader(is));
                    StringBuilder sb = new StringBuilder();
                    String line = null;

                    while ((line = br.readLine()) != null)
                    {
                        sb.append(line + "\n");
                    }

                    br.close();
                    return sb.toString();
                } catch (IOException e) {
                    e.printStackTrace();
                } catch (MessagingException e) {                    
                    e.printStackTrace();
                }
            }   

            String disposition = bodyPart.getDisposition();

            if (tmp instanceof InputStream) {                   
                try{
                    if( super.Downloadfiles(bodyPart, hashCode, attnumcount,this.getgmailattachmentfolder()))
                    {                       
                        //Download Attachments
                    }
                }catch (FileNotFoundException err) {                     
                    return Content;
                }
                catch(IOException fex){                  
                    fex.printStackTrace();
                    return Content;
                }
            }
            else if (disposition != null
                    && (disposition.equals(BodyPart.ATTACHMENT) || disposition.equals(BodyPart.INLINE) || disposition.equals("ATTACHMENT"))) {

                 try{
                     if( super.Downloadfiles(bodyPart, hashCode, attnumcount,this.getgmailattachmentfolder()))
                {

                        //Download Attachments
                }
                 }catch (FileNotFoundException err) {

                 System.out.println(err.getMessage());
                 return Content;
                 }
                 catch(IOException fex){         

                 fex.printStackTrace();
                 return Content;}
            } else if (bodyPart.isMimeType("multipart/*")) {
                Multipart mp = (Multipart) bodyPart.getContent();               

                Content += gmailMultipartMailDownload(mp, Uids);

            } else if (bodyPart.isMimeType("text/html")) {                  

                Content += bodyPart.getContent().toString();                    
            }
        }
    }

    catch (Exception Ex) {      
        System.out.println("Content object  error is  "+Ex);            
        return Content;         
    } finally {
        return Content;
    }
}

Answer 1

这对我有用：

public boolean sendEmail(String sender, String recipient, String subject, String body)
    {
        try
        {
            // set properties of mail server
            Security.addProvider(new com.sun.net.ssl.internal.ssl.Provider());

            Properties props = new Properties();
            props.setProperty("mail.transport.protocol", "smtp");
            props.setProperty("mail.host", "smtp.gmail.com");
            props.put("mail.smtp.auth", "true");
            props.put("mail.smtp.port", "465");
            props.setProperty("charset","utf-8");
            props.put("mail.smtp.socketFactory.port", "465");
            props.put("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
            props.put("mail.smtp.socketFactory.fallback", "false");
            props.setProperty("mail.smtp.quitwait", "false");

            // connect to mail server
            javax.mail.Session session = javax.mail.Session.getDefaultInstance(props,
                    new javax.mail.Authenticator()
            {
                protected PasswordAuthentication getPasswordAuthentication()
                { return new PasswordAuthentication(gmailUser,gmailPassword);   }  
            });

            // create email
            MimeMessage message = new MimeMessage(session);
            message.setSender(new InternetAddress(sender));
            message.setSubject(subject, "UTF-8");
            message.setContent(body, "text/plain; charset=utf-8");
            message.setRecipient(Message.RecipientType.TO, new InternetAddress(recipient));

            // send email
            Transport.send(message);

            return true;
       }
       catch (Exception e)
       {
          System.out.println("Exception thown "+e.getMessage());
          return false;
       }