Apache Camel框架之事务控制

本文简单介绍一下Apache Camel如何对route进行事务控制,首先介绍整个route只涉及到一个事务参与者的情况,然后再介绍route中涉及到多个事务参与者的情况.Camel是通过和Spring的框架集成进行事务控制的.

1,整个route只有一个事务参与者,"局部事务",这里用JMS的例子,后台的MQ为ActiveMQ,示例图如下:(图片来源于Camel in Action)

route的代码如下:

public class JMSTransaction extends RouteBuilder {    public void configure() throws Exception {        TProcessor0 p0 = new TProcessor0();        TProcessor1 p1 = new TProcessor1();        from("jms:queue:TOOL.DEFAULT").process(p0).process(p1).to("file:d:/temp/outbox");            }}

Spring配置如下:

<beans xmlns="http://www.springframework.org/schema/beans"       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"       xmlns:broker="http://activemq.apache.org/schema/core"       xsi:schemaLocation="       http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd       http://camel.apache.org/schema/spring http://camel.apache.org/schema/spring/camel-spring.xsd       http://activemq.apache.org/schema/core http://activemq.apache.org/schema/core/activemq-core-5.2.0.xsd">    <camelContext id="camel" xmlns="http://camel.apache.org/schema/spring">        <package>            com.test.camel.transaction.jms        </package>    </camelContext>        <bean id="jms" class="org.apache.activemq.camel.component.ActiveMQComponent">        <property name="transacted" value="true"/>        <property name="transactionManager" ref="txManager"/>                </bean>    <bean id="txManager" class="org.springframework.jms.connection.JmsTransactionManager">        <property name="connectionFactory" ref="jmsConnectionFactory"/>    </bean>    <bean id="jmsConnectionFactory" class="org.apache.activemq.ActiveMQConnectionFactory">        <property name="brokerURL" value="tcp://localhost:61616"/>            </bean></beans>

route定义的逻辑为从queue里取消息,然后进行一系列的处理(process(p0).process(p1)),<property name="transacted" value="true"/>的意思是通过这个jms进行的消息存取是有事务控制的.上面的route在process(p1)里抛出异常,txManager会进行rollback处理.(在activeMQ里,消息默认会redelivery到客户端6次,如果继续异常,消息会放到deadletter queue里(ActiveMQ.DLQ)),需要在AciveMQ的配置文件activemq.xml里配置如下:(non-persistent的queue的消息出错也转到dead letter queue)

<policyEntry queue=">">
 <deadLetterStrategy>
   <sharedDeadLetterStrategy processNonPersistent="true" />
 </deadLetterStrategy>

如果<property name="transacted" value="false"/>的话,消息在重发了6次后会丢失.

如果上面例子中的事务参与者是数据库的话,道理与之类似,只是配置的transaction manager不同,如:

<bean id="txManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"/>

Camel里使用ActiveMQ JMS的例子可以参照 http://blog.csdn.net/kkdelta/article/details/7237096

2,Camel里的全局事务,一个route里有多个事务参与者,示例图如下:(图片来源于Camel in Action)

route的定义如下:

public class XaTransaction extends RouteBuilder {    public void configure() throws Exception {        TProcessor1 p1 = new TProcessor1();        from("jms:queue:TOOL.DEFAULT")        .transacted()        .log("+++ before database +++")        .bean(SQLBean.class, "toSql")        .to("jdbc:myDataSource")        .process(p1)        .log("+++ after database +++");    }}public class SQLBean {    public String toSql(String str) {        //create table CamelTEST(msg varchar2(2000));        StringBuilder sb = new StringBuilder();        sb.append("INSERT INTO CamelTEST VALUES ('camel test')");        return sb.toString();    }}

route的逻辑是从queue里取消息,然后操作数据库,然后做后续其他操作(process(p1)),这里的process(p1)如果抛出异常的话,取消息和数据库操作都回滚,

如果整个route都成功完成的话,取消息和数据库操作提交.

这里用到JTA transaction manager是atomikos,相应的jar包可以从这里下载:http://download.csdn.net/detail/kkdelta/4056226

atomikos的主页 http://www.atomikos.com/Main/ProductsOverview

Spring的配置如下:

<beans xmlns="http://www.springframework.org/schema/beans"       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"       xmlns:broker="http://activemq.apache.org/schema/core"       xsi:schemaLocation="       http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd       http://camel.apache.org/schema/spring http://camel.apache.org/schema/spring/camel-spring.xsd       http://activemq.apache.org/schema/core http://activemq.apache.org/schema/core/activemq-core-5.2.0.xsd">       <camelContext id="camel" xmlns="http://camel.apache.org/schema/spring">        <package>            com.test.camel.transaction.xa        </package>    </camelContext>    <bean id="atomikosTransactionManager"          class="com.atomikos.icatch.jta.UserTransactionManager"          init-method="init" destroy-method="close" >        <!-- when close is called, should we force transactions to terminate or not? -->        <property name="forceShutdown" value="false"/>    </bean>    <!-- this is some atomikos setup you must do -->    <bean id="atomikosUserTransaction" class="com.atomikos.icatch.jta.UserTransactionImp" >        <property name="transactionTimeout" value="300"/>    </bean>    <!-- this is some atomikos setup you must do -->    <bean id="connectionFactory"          class="com.atomikos.jms.AtomikosConnectionFactoryBean" >        <property name="uniqueResourceName" value="amq1"/>        <property name="xaConnectionFactory" ref="jmsXaConnectionFactory"/>    </bean>    <!-- this is the Spring JtaTransactionManager which under the hood uses Atomikos -->    <bean id="jtaTransactionManager"          class="org.springframework.transaction.jta.JtaTransactionManager" >        <property name="transactionManager" ref="atomikosTransactionManager"/>        <property name="userTransaction" ref="atomikosUserTransaction"/>    </bean>    <!-- Is the ConnectionFactory to connect to the JMS broker -->    <!-- notice how we must use the XA connection factory -->    <bean id="jmsXaConnectionFactory" class="org.apache.activemq.ActiveMQXAConnectionFactory" >        <property name="brokerURL" value="tcp://localhost:61616"/>    </bean>    <!-- define the activemq Camel component so we can integrate with the AMQ broker below -->    <bean id="jms" class="org.apache.activemq.camel.component.ActiveMQComponent" >        <property name="transacted" value="true"/>        <property name="transactionManager" ref="jtaTransactionManager"/>    </bean>   <bean id="myDataSource"       class="com.atomikos.jdbc.AtomikosDataSourceBean"       init-method="init" destroy-method="close">        <!-- set an arbitrary but unique name for the datasource -->       <property name="uniqueResourceName"><value>XADBMS</value></property>       <property name="xaDataSourceClassName">          <value>oracle.jdbc.xa.client.OracleXADataSource</value>       </property>       <property name="xaProperties">                 <props>                         <prop key="user">xxx</prop>                         <prop key="password">xxx</prop>                         <prop key="URL">jdbc:oracle:thin:@147.151.240.xxx:1521:orcl</prop>                </props>       </property>          <property name="poolSize" value="1"/>    </bean>    </beans>

原文链接：http://blog.csdn.net/kkdelta/article/details/7249122