Spring集成ftp-outbound-gateway，没有远程文件

Question

I have been working on spring integration <int-ftp:outbound-gateway> ,I was able to download files from remote server with ftp-outbound-gateway , But there is one problem I could not solve yet, If remote directory contains files the system works and will complete without any issues, but If there was no files system hang up without executing from that point.I want to continue the system. whether remote folder contains files or not,

Here is the my Configuration for the ftp downloads

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

    <context:property-placeholder location="classpath:host.properties"/>

    <int:gateway id="gw" service-interface="com.util.ToFtpFlowGateway"
                 default-request-channel="inbound"/>

    <bean id="downloadProcessBean" class="com.util.FTPDownloadInterceptor">
        <property name="fileType" value="txt"/>
        <property name="sourceType" value="ftp"/>
        <property name="destinationName" value="destinationName"/>
        <property name="destinationQueName" value="destinationQueName"/>
        <property name="sourceAddressDetails" value="sourceAddressDetails"/>
        <property name="sourceName" value="sourceName"/>
    </bean>

    <bean id="ftpSessionFactory"
          class="org.springframework.integration.ftp.session.DefaultFtpSessionFactory">
        <property name="host" value="${local.host}"/>
        <property name="port" value="${local.availableServerPort}"/>
        <property name="username" value="${local.userid}"/>
        <property name="password" value="${local.user.password}"/>
    </bean>

    <int-ftp:outbound-gateway id="gatewayLS" cache-sessions="false"
                              session-factory="ftpSessionFactory"
                              request-channel="inbound"
                              command="ls"
                              command-options=""
                              expression="payload"
                              reply-channel="toSplitter" reply-timeout="10" />

    <int:channel id="toSplitter">
        <int:interceptors>
            <int:wire-tap channel="logger"/>
        </int:interceptors>
    </int:channel>

    <int:logging-channel-adapter id="logger" log-full-message="true" />

    <int:splitter id="splitter" input-channel="toSplitter" output-channel="toGet"/>

    <int-ftp:outbound-gateway id="gatewayGET" cache-sessions="false"
                              local-directory="/home/udeshika/project/req/local/download"
                              session-factory="ftpSessionFactory"
                              request-channel="toGet"
                              reply-channel="toRemoveChannel"
                              command="get"
                              command-options="-P"
                              expression="payload.remoteDirectory + '/' + payload.filename" reply-timeout="10"/>

    <int-ftp:outbound-gateway id="gatewayRM"
                              session-factory="ftpSessionFactory" cache-sessions="false"
                              expression="payload.remoteDirectory + '/'+ payload.filename"
                              request-channel="toRemoveChannel"
                              command="rm"
                              reply-channel="aggregateResultsChannel"
                              auto-create-local-directory="true"
                              reply-timeout="10"

            />
    <!--<bean id="fileDownloadIntecepter" class="shipxpress.util.FTPDownloadInterceptor"/>-->
    <int:channel id="toRemoveChannel">
        <int:interceptors>
            <int:wire-tap channel="logger2"/>
            <!--<int:ref bean="fileDownloadIntecepter" />-->
        </int:interceptors>
    </int:channel>

    <bean class="org.springframework.integration.file.FileReadingMessageSource"
          p:directory="${download.directory}"/>

    <int:logging-channel-adapter id="logger2"  log-full-message="true" />

    <int-ftp:outbound-gateway id="gatewayRM"
                              session-factory="ftpSessionFactory" cache-sessions="false"
                              expression="headers['file_remoteDirectory'] + '/' + headers['file_remoteFile']"
                              request-channel="toRemoveChannel"
                              command="rm"
                              reply-channel="aggregateResultsChannel"/>

    <int:aggregator input-channel="aggregateResultsChannel"/>

</beans>

Could anyone help me to clear this,

Thank you in advance Udeshika,

Answer 1

The problem with this flow is the LS returns an empty list; when this hits the splitter, it results in no messages and the flow stops. The thread that calls the gateway is waiting forever (by default) for a reply.

Add a reply timeout to the gateway and it will return null if no response is received.

<int:gateway id="gw" service-interface="org.springframework.integration.samples.ftp.ToFtpFlowGateway"
    default-request-channel="inbound" default-reply-timeout="100" />

As long as you use Direct channels, there's no danger of the gateway timing out when there's real work to do because the timer doesn't start until the thread returns to the gateway to look for any reply that was produced by the downstream flow.