从Gmail下载邮件附件，获取Exchange[MailMessage:null]

Question

我需要使用java程序从Gmail帐户下载附件。使用Apache Camel。

在跑步时，我得到了

Exchange[MailMessage:null]，因此附件.size（）为0

我张贴我的测试代码也

@Test
public void configureExcange() throws Exception {
    try {
        CamelContext context = new DefaultCamelContext();
        Endpoint endpoint =
                context.getEndpoint("imaps://imap.gmail.com?username=" + mailId + "&password=" + password
                        + "&delete=false&unseen=true&consumer.delay=60000");
        // PollingConsumer consumer = endpoint.createPollingConsumer();
        Exchange exchange = endpoint.createExchange();
        process(exchange);
    } catch (Exception e) {
        e.printStackTrace();
    }
}
public void process(Exchange exchange) throws Exception {
    // the API is a bit clunky so we need to loop
    Map<String, DataHandler> attachments = exchange.getIn().getAttachments();
    if (attachments.size() > 0) {
        for (String name : attachments.keySet()) {
            DataHandler dh = attachments.get(name);
            // get the file name
            String filename = dh.getName();
            // get the content and convert it to byte[]
            byte[] data = exchange.getContext().getTypeConverter().convertTo(byte[].class, dh.getInputStream());
            // write the data to a file
            FileOutputStream out = new FileOutputStream(filename);
            out.write(data);
            out.flush();
            out.close();
        }
    }
}

如何获取附件？

Answer 1

Endpoint.createExchange（）只是创建要使用的交换，它不会从邮件服务器中提取消息。您需要使用ConsumerTemplate从gmail服务器中提取消息。

Answer 2

更新函数，显示如何轮询邮件帐户。

@Test
public void configureExcange() throws Exception {
    PollingConsumer pollingConsumer = null;
    try {
        CamelContext context = new DefaultCamelContext();
        Endpoint endpoint =
                context.getEndpoint("imaps://imap.gmail.com?username="
                + mailId + "&password=" + password
                + "&delete=false&peek=false&unseen=true&consumer.delay=60000&closeFolder=false&disconnect=false");
            // options unseen=true, will only poll unread mails
            //Polling an END point
            pollingConsumer = endpoint.createPollingConsumer();
            pollingConsumer.start();
            pollingConsumer.getEndpoint().createExchange();
            Exchange exchange = pollingConsumer.receive(60000);
            while (exchange != null) {
                process(exchange);
                //each time "pollingConsumer" will poll 1 mail at a time
                exchange = pollingConsumer.receive(60000);
            }
    } catch (Exception e) {
        e.printStackTrace();
    }
}