java - 使用 Spring 集成接收邮件？

Question

我在 spring 集成中有一个简单的项目正在尝试接收邮件:

@Service
public class MailReceiverService implements CommandLineRunner {

    @Bean
    TestMailServer.ImapServer imapServer() {
        return TestMailServer.imap(0);
    }

    private static Log logger = LogFactory.getLog(MailReceiverService.class);

    public static void manageMessage() {

    @SuppressWarnings("resource")
    ClassPathXmlApplicationContext ac =
        new ClassPathXmlApplicationContext(
            "/integration/gmail-imap-idle-config.xml");
    DirectChannel inputChannel = ac.getBean("receiveChannel", DirectChannel.class);


            inputChannel.subscribe(message -> {
                logger.info("Message: " + message);
            });



  }

    @Override
    public void run(String... args) {
        manageMessage();
    }


}

gmail-imap-idle-config.xml 如下所示:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/integration https://www.springframework.org/schema/integration/spring-integration.xsd
        http://www.springframework.org/schema/integration/mail https://www.springframework.org/schema/integration/mail/spring-integration-mail.xsd
        http://www.springframework.org/schema/util https://www.springframework.org/schema/util/spring-util.xsd"
    xmlns:int="http://www.springframework.org/schema/integration"
    xmlns:int-mail="http://www.springframework.org/schema/integration/mail"
    xmlns:util="http://www.springframework.org/schema/util">

    <int:channel id="receiveChannel" />
    <int-mail:imap-idle-channel-adapter id="customAdapter"
            store-uri="imaps://username:password@imap.gmail.com:993/inbox"
            channel="receiveChannel"
            auto-startup="true"
            should-delete-messages="false"
            should-mark-messages-as-read="false"
            java-mail-properties="javaMailProperties"/>

    <util:properties id="javaMailProperties">
        <prop key="mail.imap.socketFactory.class">javax.net.ssl.SSLSocketFactory</prop>
        <prop key="mail.imap.socketFactory.fallback">false</prop>
        <prop key="mail.store.protocol">imaps</prop>
        <prop key="mail.debug">false</prop>
    </util:properties>

</beans>

但是当我运行它时，我收到以下消息:

channel “application.errorChannel”有 0 个订阅者。停止 bean '_org.springframework.integration.errorLogger'

然后它就关闭了!关于如何让它发挥作用有什么建议吗？谢谢!

Answer 1

您的问题是您没有使应用程序保持 Activity 状态。 <int-mail:imap-idle-channel-adapter>在后台启动一个长期运行的进程。但是，当您启动应用程序时，您会立即离开主线程，然后主线程就会退出。与此同时，您会从电子邮箱收到一条消息，但订阅者是 receiveChannel已经消失了，因为您的应用程序根据主线程行为处于关闭状态。

考虑设置一些障碍 run()不要让主线程退出。

在示例中，我们通常有这样的内容:

System.out.println("Hit 'Enter' to terminate");
System.in.read();
ctx.close();

这样您就不会让 JVM 退出，因此您将收到电子邮件，直到您终止应用程序。