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spring-integration/spring-integration-reference/src/mail.xml
Mark Fisher c030359678 INT-934
2009-12-22 15:59:49 +00:00

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7.2 KiB
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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd">
<chapter id="mail">
<title>Mail Support</title>
<section id="mail-outbound">
<title>Mail-Sending Channel Adapter</title>
<para>
Spring Integration provides support for outbound email with the
<classname>MailSendingMessageHandler</classname>. It delegates to a configured instance of Spring's
<interfacename>JavaMailSender</interfacename>:
<programlisting language="java"> JavaMailSender mailSender = (JavaMailSender) context.getBean("mailSender");
MailSendingMessageHandler mailSendingHandler = new MailSendingMessageHandler(mailSender);</programlisting>
<classname>MailSendingMessageHandler</classname> has various mapping strategies that use Spring's
<interfacename>MailMessage</interfacename> abstraction. If the received Message's payload is already
a MailMessage instance, it will be sent directly. Therefore, it is generally recommended to precede this
consumer with a Transformer for non-trivial MailMessage construction requirements. However, a few simple
Message mapping strategies are supported out-of-the-box. For example, if the message payload is a byte array,
then that will be mapped to an attachment. For simple text-based emails, you can provide a String-based
Message payload. In that case, a MailMessage will be created with that String as the text content. If you
are working with a Message payload type whose toString() method returns appropriate mail text content, then
consider adding Spring Integration's <emphasis>ObjectToStringTransformer</emphasis> prior to the outbound
Mail adapter (see the example within <xref linkend="transformer-namespace"/> for more detail).
</para>
<para>
The outbound MailMessage may also be configured with certain values from the
<classname>MessageHeaders</classname>. If available, values will be mapped to the outbound mail's
properties, such as the recipients (TO, CC, and BCC), the from/reply-to, and the subject. The header names are
defined by the following constants:
<programlisting language="java"> MailHeaders.SUBJECT
MailHeaders.TO
MailHeaders.CC
MailHeaders.BCC
MailHeaders.FROM
MailHeaders.REPLY_TO</programlisting>
</para>
</section>
<section id="mail-inbound">
<title>Mail-Receiving Channel Adapter</title>
<para>
Spring Integration also provides support for inbound email with the
<classname>MailReceivingMessageSource</classname>. It delegates to a configured instance of Spring
Integration's own <interfacename>MailReceiver</interfacename> interface, and there are two implementations:
<classname>Pop3MailReceiver</classname> and <classname>ImapMailReceiver</classname>. The easiest way to
instantiate either of these is by passing the 'uri' for a Mail store to the receiver's constructor. For example:
<programlisting language="java"><![CDATA[ MailReceiver receiver = new Pop3MailReceiver("pop3://usr:pwd@localhost/INBOX");
]]></programlisting>
</para>
<para>
Another option for receiving mail is the IMAP "idle" command (if supported by the mail server you are using).
Spring Integration provides the <classname>ImapIdleChannelAdapter</classname> which is itself a Message-producing
endpoint. It delegates to an instance of the <classname>ImapMailReceiver</classname> but enables asynchronous
reception of Mail Messages. There are examples in the next section of configuring both types of inbound Channel
Adapter with Spring Integration's namespace support in the 'mail' schema.
</para>
</section>
<section id="mail-namespace">
<title>Mail Namespace Support</title>
<para>
Spring Integration provides a namespace for mail-related configuration. To use it, configure the following schema
locations.<programlisting language="xml"><![CDATA[<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:mail="http://www.springframework.org/schema/integration/mail"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
http://www.springframework.org/schema/integration/mail
http://www.springframework.org/schema/integration/mail/spring-integration-mail-1.0.xsd">]]></programlisting>
</para>
<para>
To configure an outbound Channel Adapter, provide the channel to receive from, and the MailSender:
<programlisting language="xml"><![CDATA[<mail:outbound-channel-adapter channel="outboundMail"
mail-sender="mailSender"/>]]></programlisting>
Alternatively, provide the host, username, and password:
<programlisting language="xml"><![CDATA[<mail:outbound-channel-adapter channel="outboundMail"
host="somehost" username="someuser" password="somepassword"/>]]></programlisting>
<note>
Keep in mind, as with any outbound Channel Adapter, if the referenced channel is a PollableChannel, a
&lt;poller&gt; sub-element should be provided with either an interval-trigger or cron-trigger.
</note>
</para>
<para>
To configure an inbound Channel Adapter, you have the choice between polling or event-driven (assuming your
mail server supports IMAP IDLE - if not, then polling is the only option). A polling Channel Adapter simply
requires the store URI and the channel to send inbound Messages to. The URI may begin with "pop3" or "imap":
<programlisting language="xml"><![CDATA[ <mail:inbound-channel-adapter channel="mailIn"
store-uri="imap://usr:pwd@imap.example.com/INBOX">
<poller max-messages-per-poll="3">
<interval-trigger interval="30" time-unit="SECONDS"/>
</poller>
</mail:inbound-channel-adapter>]]></programlisting>
If you do have IMAP idle support, then you may want to configure the "imap-idle-channel-adapter" element instead.
Since the "idle" command enables event-driven notifications, no poller is necessary for this adapter. It will
send a Message to the specified channel as soon as it receives the notification that new mail is available:
<programlisting language="xml"><![CDATA[ <mail:imap-idle-channel-adapter channel="mailIn"
store-uri="imaps://usr:pwd@imap.example.com:993/INBOX"/>]]></programlisting>
</para>
<para>
When using the namespace support, a <emphasis>header-enricher</emphasis> Message Transformer is also available.
This simplifies the application of the headers mentioned above to any Message prior to sending to the
Mail-sending Channel Adapter.
<programlisting language="xml"><![CDATA[<mail:header-enricher subject="Example Mail"
to="to@example.org"
cc="cc@example.org"
bcc="bcc@example.org"
from="from@example.org"
reply-to="replyTo@example.org"
overwrite="false"/>]]></programlisting>
</para>
</section>
</chapter>