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spring+ibatis实现读写分离

• 特点
  无缝结合spring+ibatis，对于程序员来说，是透明的
  除了修改配置信息之外，程序的代码不需要修改任何东西
  支持spring的容器事务

• 规则:

  1. 基于spring配置的容器事务
  2. 读写事务到主库
  3. 只读事务到从库
  4. 如果没有配置事务，更新语句全部到主库，查询语句均衡到从库
     源码地址
     qq讨论群：261502547
• 快速入门
  maven依赖

<dependency>
    <groupId>org.springmore</groupId>
    <artifactId>springmore-core</artifactId>
    <version>1.0.0</version>
</dependency>

dataSource配置(applicationContext.xml中)

<?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"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans 
        http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context-3.0.xsd
        ">
    <!-- C3P0连接池配置 -->
    <bean id="master" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass">
            <value>com.mysql.jdbc.Driver</value>
        </property>
        <property name="jdbcUrl">
            <value>jdbc:mysql://192.168.1.246:3306/db1</value>
        </property>
        <property name="user">
            <value>ysb</value>
        </property>
        <property name="password">
            <value>ysb</value>
        </property>
        <property name="initialPoolSize">
            <value>20</value>
        </property>
        <property name="minPoolSize">
            <value>20</value>
        </property>
        <property name="maxPoolSize">
            <value>200</value>
        </property>
        <property name="maxIdleTime">
            <value>255000</value>
        </property>
    </bean>

    <bean id="dataSource2" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass">
            <value>com.mysql.jdbc.Driver</value>
        </property>
        <property name="jdbcUrl">
            <value>jdbc:mysql://192.168.1.246:3306/db2</value>
        </property>
        <property name="user">
            <value>ysb</value>
        </property>
        <property name="password">
            <value>ysb</value>
        </property>
        <property name="initialPoolSize">
            <value>20</value>
        </property>
        <property name="minPoolSize">
            <value>20</value>
        </property>
        <property name="maxPoolSize">
            <value>200</value>
        </property>
        <property name="maxIdleTime">
            <value>255000</value>
        </property>
    </bean>

    <bean id="dataSource3" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass">
            <value>com.mysql.jdbc.Driver</value>
        </property>
        <property name="jdbcUrl">
            <value>jdbc:mysql://192.168.1.246:3306/db3</value>
        </property>
        <property name="user">
            <value>ysb</value>
        </property>
        <property name="password">
            <value>ysb</value>
        </property>
        <property name="initialPoolSize">
            <value>20</value>
        </property>
        <property name="minPoolSize">
            <value>20</value>
        </property>
        <property name="maxPoolSize">
            <value>200</value>
        </property>
        <property name="maxIdleTime">
            <value>255000</value>
        </property>
    </bean>

    <bean id="dataSource" class="org.springmore.core.datasource.DynamicDataSource">
        <property name="master" ref="master" />     
        <property name="slaves">
            <list>
                <ref bean="dataSource2"/>
                <ref bean="dataSource3"/>
            </list>         
        </property>
    </bean>
</beans>

整合mybatis配置(applicationContext.xml中)

    <!-- ibatis3 工厂类 -->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <property name="configLocation" value="classpath:sqlMapConfig.xml" />
    </bean>
    <bean id="sqlSessionTemplate" class="org.mybatis.spring.SqlSessionTemplate">
        <constructor-arg index="0" ref="sqlSessionFactory" />
    </bean>

    <bean id="dynamicSqlSessionTemplate" class="org.springmore.core.datasource.DynamicSqlSessionTemplate">
        <constructor-arg index="0" ref="sqlSessionTemplate" />
    </bean>

事务配置(applicationContext.xml中)

    <!-- 定义单个jdbc数据源的事务管理器 -->
    <bean id="transactionManager"
        class="org.springmore.core.datasource.DynamicDataSourceTransactionManager">
        <property name="dataSource" ref="dataSource" />
    </bean>
    <!-- 以 @Transactional 标注来定义事务  -->
    <tx:annotation-driven transaction-manager="transactionManager"
        proxy-target-class="true" />        

    <!-- 配置事务的传播特性 -->
    <tx:advice id="txAdvice" transaction-manager="transactionManager">
        <tx:attributes>
            <tx:method name="insert*" propagation="REQUIRED" read-only="false"
                rollback-for="Exception" />
            <tx:method name="delete*" propagation="REQUIRED" read-only="false"
                rollback-for="Exception" />
            <tx:method name="update*" propagation="REQUIRED" read-only="false"
                rollback-for="Exception" />
            <tx:method name="proc*" propagation="REQUIRED" read-only="false"
                rollback-for="Exception" />
            <tx:method name="select*" read-only="true" />
            <tx:method name="*" read-only="false" />
            <!-- <tx:method name="*" read-only="true" /> -->
        </tx:attributes>
    </tx:advice>
    <!-- 那些类的哪些方法参与事务 -->
    <aop:config>
        <aop:pointcut id="allManagerMethod" expression="execution(* org.springmore.core.dao..*(..))" />
        <aop:advisor pointcut-ref="allManagerMethod" advice-ref="txAdvice" />
    </aop:config>

dao代码示例：

@Repository("UserMapperImpl")
public class UserMapperImpl implements UserMapper{

    @Autowired
    private DynamicSqlSessionTemplate sqlSessionTemplate;

    //从库
    public List<User> selectByUserNameAndPwd(User user) {
        return sqlSessionTemplate.selectList("selectByUserNameAndPwd", user);
    }

    //主库
    public void insert(User user) { 
        sqlSessionTemplate.insert("insert", user);      
    }
}