dubbo怎样处理事务一致性

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mob64ca13f937ae 2024-09-07 21:58:37

文章标签 dubbo怎样处理事务一致性 java 数据库 spring xml 文章分类 运维

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

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.

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