无法使用Spring读取电子邮件正文：javax.mail.FolderClosedException

Question

我正在尝试监听我的Gmail收件箱中的传入邮件。每次收到新邮件时，我都想查看其主题和内容。

到目前为止，我有这个：

import java.io.IOException;

import javax.mail.BodyPart;
import javax.mail.Folder;
import javax.mail.internet.ContentType;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.commons.mail.util.MimeMessageParser;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.integration.channel.DirectChannel;
import org.springframework.integration.mail.transformer.MailToStringTransformer;
import org.springframework.messaging.Message;
import org.springframework.messaging.MessageHandler;
import org.springframework.messaging.MessagingException;


public class GmailInboundImapIdleAdapterTestApp {
    private static Log logger = LogFactory.getLog(GmailInboundImapIdleAdapterTestApp.class);

    public static void main (String[] args) throws Exception {
        @SuppressWarnings("resource")
        ClassPathXmlApplicationContext ac = new ClassPathXmlApplicationContext("/META-INF/spring/integration/gmail-imap-idle-config.xml");

        DirectChannel inputChannel = ac.getBean("receiveChannel", DirectChannel.class);

        inputChannel.subscribe(new MessageHandler() {
            public void handleMessage(Message<?> message){
                    MimeMessage mm = (MimeMessage) message.getPayload();
                    try {
                        System.out.println("Subject: "+mm.getSubject());
                        System.out.println("Body: "+readPlainContent(mm));
                    } 
                    catch (javax.mail.MessagingException e) {

                        System.out.println("MessagingException: "+e.getMessage());
                        e.printStackTrace();
                    }
                    catch (Exception e) {
                        System.out.println("Exception: "+e.getMessage());
                        e.printStackTrace();
                    }

            }
        });
    }

     private static String readHtmlContent(MimeMessage message) throws Exception {
            return new MimeMessageParser(message).parse().getHtmlContent();
        }

    private static String readPlainContent(MimeMessage message) throws Exception {
            return new MimeMessageParser(message).parse().getPlainContent();
        }
}

它可以正确读取邮件主题。但是邮件正文没有运气。javax.mail.FolderClosedException打了我一下。如何解决这个问题？

Answer 1

如加里所说：simple-content="true"或最近以来autoCloseFolder = false：https://docs.spring.io/spring-integration/docs/5.2.0.RELEASE/reference/html/mail.html#mail-inbound

从5.2版开始，autoCloseFolder选项在邮件接收器上提供。将其设置为false不会在获取后自动关闭文件夹，而是将IntegrationMessageHeaderAccessor.CLOSEABLE_RESOURCE标头（有关更多信息，请参见MessageHeaderAccessor API）填充到从通道适配器发给生产者的每条消息中。目标应用程序有责任在下游流程中必要时调用此标头上的close()：