JMS消息傳遞是一種異步過(guò)程，如果沒(méi)有接受者JMS Provider應(yīng)該選擇將消息持久化，策略主要有文件持久化和基于數(shù)據(jù)庫(kù)的持久化兩種，下文是關(guān)于將未消費(fèi)的消息持久化到MySql數(shù)據(jù)庫(kù)的。
首先，我們要做的是將MySql數(shù)據(jù)庫(kù)的驅(qū)動(dòng)包放置到ActiveMQ的安裝目錄下的lib里。
其次，我們需要改寫(xiě)activemq.xml文件，它在ActiveMQ的conf目錄中。具體修改部分請(qǐng)見(jiàn)下文中粗體部分：
<!--
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this work for additional information regarding copyright ownership.
The ASF licenses this file to You under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
-->
<beans
xmlns="http://www.springframework.org/schema/beans"
xmlns:amq="http://activemq.apache.org/schema/core"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd
http://activemq.apache.org/schema/core http://activemq.apache.org/schema/core/activemq-core.xsd">
<!-- Allows us to use system properties as variables in this configuration file -->
<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="locations">
<value>file:${activemq.base}/conf/credentials.properties</value>
</property>
</bean>
<!--
The <broker> element is used to configure the ActiveMQ broker.
-->
<broker xmlns="http://activemq.apache.org/schema/core" brokerName="localhost" dataDirectory="${activemq.base}/data">
<!--
The managementContext is used to configure how ActiveMQ is exposed in
JMX. By default, ActiveMQ uses the MBean server that is started by
the JVM. For more information, see:
http://activemq.apache.org/jmx.html
-->
<managementContext>
<managementContext createConnector="false"/>
</managementContext>
<!--
Configure message persistence for the broker. The default persistence
mechanism is the KahaDB store (identified by the kahaDB tag).
For more information, see:
http://activemq.apache.org/persistence.html
-->
<persistenceAdapter>
<jdbcPersistenceAdapter dataSource="#mysqlDataSource"/>
</persistenceAdapter>
<!--
For better performances use VM cursor and small memory limit.
For more information, see:
http://activemq.apache.org/message-cursors.html
Also, if your producer is "hanging", it's probably due to producer flow control.
For more information, see:
http://activemq.apache.org/producer-flow-control.html
-->
<destinationPolicy>
<policyMap>
<policyEntries>
<policyEntry topic=">" producerFlowControl="true" memoryLimit="1mb">
<pendingSubscriberPolicy>
<vmCursor />
</pendingSubscriberPolicy>
</policyEntry>
<policyEntry queue=">" producerFlowControl="true" memoryLimit="1mb">
<!-- Use VM cursor for better latency
For more information, see:
http://activemq.apache.org/message-cursors.html
<pendingQueuePolicy>
<vmQueueCursor/>
</pendingQueuePolicy>
-->
</policyEntry>
</policyEntries>
</policyMap>
</destinationPolicy>
<!--
The systemUsage controls the maximum amount of space the broker will
use before slowing down producers. For more information, see:
http://activemq.apache.org/producer-flow-control.html
<systemUsage>
<systemUsage>
<memoryUsage>
<memoryUsage limit="20 mb"/>
</memoryUsage>
<storeUsage>
<storeUsage limit="1 gb" name="foo"/>
</storeUsage>
<tempUsage>
<tempUsage limit="100 mb"/>
</tempUsage>
</systemUsage>
</systemUsage>
-->
<!--
The transport connectors expose ActiveMQ over a given protocol to
clients and other brokers. For more information, see:
http://activemq.apache.org/configuring-transports.html
-->
<transportConnectors>
<transportConnector name="openwire" uri="tcp://0.0.0.0:61616"/>
</transportConnectors>
</broker>
<!-- MySql dataSource -->
<bean id="mysqlDataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
<property name="driverClassName" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost/test?relaxAutoCommit=true"/>
<property name="username" value="root"/>
<property name="password" value="hy"/>
<property name="poolPreparedStatements" value="true"/>
</bean>
<!--
Uncomment to enable Camel
Take a look at activemq-camel.xml for more details
<import resource="camel.xml"/>
-->
<!--
Enable web consoles, REST and Ajax APIs and demos
Take a look at activemq-jetty.xml for more details
-->
<import resource="jetty.xml"/>
</beans>
如上，在persistenceAdapter節(jié)點(diǎn)中指定mySql數(shù)據(jù)源，在broker節(jié)點(diǎn)外配置了bean：
<!-- MySql dataSource -->
<bean id="mysqlDataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
<property name="driverClassName" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost/test?relaxAutoCommit=true"/>
<property name="username" value="root"/>
<property name="password" value="hy"/>
<property name="poolPreparedStatements" value="true"/>
</bean>
上面加粗的一句指明了消息存儲(chǔ)在mysql的test數(shù)據(jù)庫(kù)中，當(dāng)然你可以指定成任何你想要的數(shù)據(jù)庫(kù)，注意在啟動(dòng)ActiveMq之前這個(gè)數(shù)據(jù)庫(kù)是要存在的，否則報(bào)錯(cuò)。另外需要贅述的一點(diǎn)是activemq.xml中不要有中文，看來(lái)白狗子對(duì)非英語(yǔ)的抵觸真是無(wú)處不在，我們所有中國(guó)人應(yīng)該奮發(fā)圖強(qiáng)恢復(fù)漢唐明榮光，讓異族不得不仰視我們，當(dāng)然這是后話。
下面就可以啟動(dòng)ActiveMQ了，向隊(duì)列發(fā)送幾條消息后，我們可以看看數(shù)據(jù)庫(kù)里發(fā)生了什么變化，如下：
上圖是ActiveMQ為了持久化消息而設(shè)立的三張表。
上圖是持久化到數(shù)據(jù)庫(kù)的未被消費(fèi)掉的消息。
如果這些待消費(fèi)消息被接收后，這張表就會(huì)空空如也，如下：
你可以使用
這個(gè)程序（注意包要自己導(dǎo)入一下）來(lái)測(cè)試一下。
以上就是將ActiveMQ中未消費(fèi)的消息持久化到MySql數(shù)據(jù)庫(kù)的過(guò)程，但愿對(duì)你有所幫助。