dubbo服务+Spring事务+AOP动态数据源切换 出错
原文链接：http://www.cnblogs.com/wangdaijun/p/5281912.html
http://www.linkedkeeper.com/detail/blog.action?bid=1043
1：问题描述，以及分析
项目用了spring数据源动态切换，服务用的是dubbo。在运行一段时间后程序异常,更新操作没有切换到主库上。
这个问题在先调用读操作后再调用写操作会出现。
经日志分析原因：
第一：当程序运行一段时间后调用duboo服务时..([DubboServerHandler-192.168.1.106:20880-thread-199] [DubboServerHandler-192.168.1.106:20880-thread-200]) dubbo服务默认最大200线程(超过200个线程以后服务不会创建新的线程了)，读操作与写操作有可能会在一个线程里（读操作的事务propagation是supports,写是required），当这种情况出现时MethodBeforeAdvice.before先执行，DataSourceSwitcher.setSlave()被调用，然后DynamicDataSource.determineCurrentLookupKey（此方法调用contextHolder.get获取数据源的key）被调用，此时数据源指向从库也就是只读库。当读操作执行完成后，dubbo在同一个线程(thead-200)里执行更新的操作（比如以update,insert开头的服务方法），这时会先执行DynamicDataSource.determineCurrentLookupKey，指向的是读库，然后执行MethodBeforeAdvice.before，DataSourceSwitcher.setMaster()被调用，注意，这时DynamicDataSource.determineCurrentLookupKey不会被再次调用，所以这时数据源仍然指向读库，异常发生了。(写从库了)
DynamicDataSource.determineCurrentLookupKey 与DataSourceSwitcher.setXXX()方法的执行顺序是导致问题的关键，这个跟事务的advice与动态设置数据源的advice执行顺序有关.
2：application.xml配置
<bean id="parentDataSource" class="org.apache.commons.dbcp2.BasicDataSource"> <property name="driverClassName" value="com.mysql.jdbc.Driver"/> <property name="initialSize" value="20"/> <property name="maxTotal" value="50"/> <property name="maxIdle" value="10"/> <property name="testOnBorrow" value="true"/> <property name="testWhileIdle" value="true"/> <property name="testOnReturn" value="true"/> <property name="defaultAutoCommit" value="false"/> </bean> <!-- 主数据源--> <bean id="masterDataSource" parent="parentDataSource"> <property name="url" value="jdbc:mysql://192.168.60.45:13306/ac_vote?autoReconnect=true&useSSL=false"/> <property name="username" value="data"/> <property name="password" value="acfundata"/> </bean> <!-- 从数据源--> <bean id="slaveDataSource" parent="parentDataSource"> <property name="url" value="jdbc:mysql://192.168.60.45:23306/ac_vote?autoReconnect=true&useSSL=false"/> <property name="username" value="data"/> <property name="password" value="acfundata"/> </bean> <!-- 配置自定义动态数据源--> <bean id="dataSource" class="tv.acfun.service.common.database.DynamicDataSource"> <property name="targetDataSources"> <map key-type="java.lang.String"> <entry key="slave" value-ref="slaveDataSource" /> <entry key="master" value-ref="masterDataSource" /> </map> </property> <property name="defaultTargetDataSource" ref="masterDataSource" /> </bean> <!--开启自动代理功能 true使用CGLIB --> <aop:aspectj-autoproxy proxy-target-class="true"/> <!-- 声明AOP 切换数据源通知 类中加@Component 自动扫描xml中不用配<bean>了 <bean id="dataSourceAdvice" class="tv.acfun.service.vote.aop.DataSourceAdvice" /> --> <!-- 配置通知和切点 注意这个一定要配置在事务声明(txAdvice)之前 否则就会出现数据源切换出错 --> <aop:config> <aop:advisor pointcut="execution(* tv.acfun.service.vote.manager.impl.*ManagerImpl.*(..))" advice-ref="dataSourceAdvice" /> </aop:config> <!-- 配置事务管理器--> <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"> <property name="dataSource" ref="dataSource" /> </bean> 方式① <!--开启注解式事务扫描 要开启事务的service实现类中 加上@Transactional注解--> <tx:annotation-driven/> 方式②(注释中) <!--未开启事务扫描时 需指定aop配置 声明那些类的哪些方法参与事务--start <tx:advice id="txAdvice" transaction-manager="transactionManager"> <tx:attributes> <tx:method name="add*" propagation="REQUIRED" /> <tx:method name="create*" propagation="REQUIRED" /> <tx:method name="save*" propagation="REQUIRED"/> <tx:method name="edit*" propagation="REQUIRED" /> <tx:method name="update*" propagation="REQUIRED" /> <tx:method name="delete*" propagation="REQUIRED" /> <tx:method name="remove*" propagation="REQUIRED" /> <tx:method name="find*" propagation="REQUIRED" read-only="true" /> <tx:method name="query*" propagation="SUPPORTS" read-only="true" /> <tx:method name="get*" propagation="SUPPORTS" read-only="true" /> <!-- 对其它方法进行只读事务 --> <!--<tx:method name="*" propagation="SUPPORTS" read-only="true" />--> </tx:attributes> </tx:advice> <aop:config> <aop:advisor pointcut="execution(* tv.acfun.service.vote.manager..*Service.*(..))" advice-ref="txAdvice" /> <aop:advisor pointcut="execution(* tv.acfun.service.vote.manager..*ServiceImpl.*(..))" advice-ref="txAdvice" /> </aop:config> 方式② end -->
3. DataSourceAdvice类
@Slf4j @Aspect @Component public class DataSourceAdvice implements MethodBeforeAdvice, AfterReturningAdvice, ThrowsAdvice { // service方法执行之前被调用 public void before(Method method, Object[] args, Object target) throws Throwable { log.info("切入点: " + target.getClass().getName() + "类中" + method.getName() + "方法"); if (method.getName().startsWith("insert") || method.getName().startsWith("create") || method.getName().startsWith("save") || method.getName().startsWith("edit") || method.getName().startsWith("update") || method.getName().startsWith("delete") || method.getName().startsWith("remove")) { log.info("切换到: master"); DataSourceSwitcher.setMaster(); } else { log.info("切换到: slave"); DataSourceSwitcher.setSlave(); } } // service方法执行完之后被调用 public void afterReturning(Object var1, Method var2, Object[] var3, Object var4) throws Throwable { DataSourceSwitcher.setMaster(); // ***** 加上这句解决运行数据库切换问题 } // 抛出Exception之后被调用 public void afterThrowing(Method method, Object[] args, Object target, Exception ex) throws Throwable { DataSourceSwitcher.setSlave(); log.info("出现异常,切换到: slave"); }
4. DataSourceSwitcher 类
public class DataSourceSwitcher { private static final ThreadLocal contextHolder = new ThreadLocal(); private static final String DATA_SOURCE_SLAVE = "slave" ; public static void setDataSource(String dataSource) { Assert.notNull(dataSource, "dataSource cannot be null"); contextHolder.set(dataSource); } public static void setMaster(){ clearDataSource(); } public static void setSlave() { setDataSource( DATA_SOURCE_SLAVE); } public static String getDataSource() { return (String) contextHolder.get(); } public static void clearDataSource() { contextHolder.remove(); } }
5. DynamicDataSource 类
public class DynamicDataSource extends AbstractRoutingDataSource { @Override protected Object determineCurrentLookupKey() { return DataSourceSwitcher.getDataSource(); } }
和 http://my.oschina.net/mrXhuangyang/blog/500743 这个遇到一样问题
或者基于注解@Aspect切面
<?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:tx="http://www.springframework.org/schema/tx" xmlns:aop="http://www.springframework.org/schema/aop" xsi:schemaLocation="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 http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd" default-autowire="byName"> <bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"> <property name="locations"> <list> <value>classpath:system.properties</value> </list> </property> </bean> <context:component-scan base-package="com.xxx.service.main"/> <!-- config mybatis --> <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"> <property name="dataSource" ref="dataSource"/> <property name="configLocation" value="classpath:/mybatis/mybatis-config.xml"/> <property name="typeAliasesPackage" value="com.xxx.service.entity"/> <property name="mapperLocations" value="classpath*:/mybatis/*Mapper.xml"/> </bean> <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer"> <property name="basePackage" value="com.xxx.service.main.dao"/> <property name="annotationClass" value="com.xxx.service.main.dao.MyBatisRepository"/> </bean> <bean id="parentDataSource" class="org.apache.commons.dbcp2.BasicDataSource"> <property name="driverClassName" value="com.mysql.jdbc.Driver"/> <property name="initialSize" value="20"/> <property name="maxTotal" value="50"/> <property name="maxIdle" value="10"/> <property name="testOnBorrow" value="true"/> <property name="testWhileIdle" value="true"/> <property name="testOnReturn" value="true"/> <property name="defaultAutoCommit" value="false"/> </bean> <bean id="masterDataSource" parent="parentDataSource"> <property name="url" value="jdbc:mysql://mysql.xxx.com:3306/system32?useUnicode=true&characterEncoding=UTF-8&zeroDateTimeBehavior=convertToNull&transformedBitIsBoolean=true"/> <property name="username" value="cache"/> <property name="password" value="test2"/> </bean> <!-- 从数据源--> <bean id="slaveDataSource" parent="parentDataSource"> <property name="url" value="jdbc:mysql://mysql-slave.xxx.com:3306/system32?useUnicode=true&characterEncoding=UTF-8&zeroDateTimeBehavior=convertToNull&transformedBitIsBoolean=true"/> <property name="username" value="cache"/> <property name="password" value="test2"/> </bean> <bean id="dataSource" class="com.xxx.service.common.database.DynamicDataSource"> <property name="targetDataSources"> <map key-type="java.lang.String"> <entry key="slave" value-ref="slaveDataSource" /> </map> </property> <property name="defaultTargetDataSource" ref="masterDataSource" /> </bean> <!--开启@Aspect注解支持--> <aop:aspectj-autoproxy/> <!--定义事务管理器--> <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"> <property name="dataSource" ref="dataSource" /> </bean> <!-- annotation-driven就是支持事务注解的(@Transaction) --> <tx:annotation-driven transaction-manager="transactionManager"/> <!-- config redis --> <bean id="poolConfig" class="redis.clients.jedis.JedisPoolConfig"> <property name="maxIdle" value="${spring.redis.pool.max-idle}" /> <property name="maxTotal" value="${spring.redis.pool.max-active}" /> <property name="minIdle" value="${spring.redis.pool.min-idle}" /> <property name="maxWaitMillis" value="${spring.redis.pool.max-wait}" /> </bean> <bean id="connectionFactory" class="org.springframework.data.redis.connection.jedis.JedisConnectionFactory"> <property name="hostName" value="${spring.redis.host}" /> <property name="port" value="${spring.redis.port}" /> <property name="poolConfig" ref="poolConfig" /> </bean> <bean id="stringRedisTemplate" class="org.springframework.data.redis.core.StringRedisTemplate"> <property name="connectionFactory" ref="connectionFactory" /> </bean> <bean id="redisTemplate" class="org.springframework.data.redis.core.RedisTemplate"> <property name="connectionFactory" ref="connectionFactory" /> <!-- key的序列化配置,不配置的话key值会有乱码 --> <property name="keySerializer"> <bean class="org.springframework.data.redis.serializer.StringRedisSerializer" /> </property> <property name="hashKeySerializer"> <bean class="org.springframework.data.redis.serializer.StringRedisSerializer" /> </property> </bean> </beans>
@Aspect切面类
package tv.acfun.service.main.aop; import lombok.extern.slf4j.Slf4j; import org.aspectj.lang.JoinPoint; import org.aspectj.lang.annotation.*; import org.aspectj.lang.reflect.MethodSignature; import org.springframework.aop.AfterReturningAdvice; import org.springframework.aop.MethodBeforeAdvice; import org.springframework.aop.ThrowsAdvice; import org.springframework.core.annotation.Order; import org.springframework.stereotype.Component; import tv.acfun.service.common.database.DataSourceSwitcher; import java.lang.reflect.Method; /** * @author xxx * @date 2016-11-24 * @what 读写分离切面类 */ @Slf4j @Component @Aspect public class DataSourceAspect { @Pointcut("execution(* com.xxx.service.main.manager.impl.*ManagerImpl.*(..))") private void aspectjMethod(){} // service方法执行之前被调用 @Before(value = "aspectjMethod()") public void before(JoinPoint joinPoint) throws Throwable { MethodSignature methodSignature = (MethodSignature) joinPoint.getSignature(); Method method = methodSignature.getMethod(); log.debug("切入点: " + joinPoint.getTarget().getClass().getName() + "类中" + method.getName() + "方法"); if(method.getName().startsWith("add") || method.getName().startsWith("insert") || method.getName().startsWith("create") || method.getName().startsWith("save") || method.getName().startsWith("edit") || method.getName().startsWith("update") || method.getName().startsWith("delete") || method.getName().startsWith("remove")){ log.debug("切换到: master"); DataSourceSwitcher.setMaster(); }else { log.debug("切换到: slave"); DataSourceSwitcher.setSlave(); } } }
AOP方式资料:http://www.360doc.com/content/12/0602/15/7656232_215420487.shtml
另外看到一个文章讲
@Order(-1)
DataSourceAdvice前面加上一个Order注解 可以保证 数据源切换通知 在 事务通知前执行.
