0.数据库sharding基本思想
水平切分：把表的数据按某种规则（比如按ID散列）切分到多张表或者多个数据库(server)上。
垂直切分：把关系紧密（比如同一模块）的表切分出来放在一个server上。
1.sharding-jdbc
当当开源中间件：https://github.com/dangdangdotcom/sharding-jdbc
注意：Sharding-jdbc目前实现的是水平切分，垂直切分配置暂未实现！
2.架构图
3.maven pom.xml
<dependency>
<groupId>com.dangdang</groupId>
<artifactId>sharding-jdbc-core</artifactId>
<version>1.0.0</version>
</dependency>4.spring+mybatis+sharding-jdbc完整配置
配置文件基于github demo
<?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:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx"
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
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-3.0.xsd">
<!-- 0.spring upload config -->
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
<property name="defaultEncoding" value="utf-8"></property>
<property name="maxUploadSize" value="10485760000"></property>
<property name="maxInMemorySize" value="10960"></property>
</bean>
<!-- 1.配置扫描包service,dao -->
<context:component-scan base-package="com.ccy.*"/>
<!-- 2.配置属性文件jdbc.properties -->
<context:property-placeholder location="classpath:jdbc.properties"/>
<!-- 3.配置数据源dataSource -->
<bean id="ds_0" class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close">
<property name="driverClass" value="com.mysql.jdbc.Driver"/>
<property name="jdbcUrl" value="jdbc:mysql://localhost:3306/ds_0"/>
<property name="user" value="root"/>
<property name="password" value="root"/>
</bean>
<bean id="ds_1" class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close">
<property name="driverClass" value="com.mysql.jdbc.Driver"/>
<property name="jdbcUrl" value="jdbc:mysql://localhost:3306/ds_1"/>
<property name="user" value="root"/>
<property name="password" value="root"/>
</bean>
<bean id="dataSourceRule" class="com.dangdang.ddframe.rdb.sharding.api.rule.DataSourceRule">
<constructor-arg>
<map>
<entry key="ds_0" value-ref="ds_0"/>
<entry key="ds_1" value-ref="ds_1"/>
</map>
</constructor-arg>
</bean>
<bean id="orderTableRule" class="com.dangdang.ddframe.rdb.sharding.api.rule.TableRule">
<constructor-arg value="t_order" index="0"/>
<constructor-arg index="1">
<list>
<value>t_order_0</value>
<value>t_order_1</value>
</list>
</constructor-arg>
<constructor-arg index="2" ref="dataSourceRule"/>
</bean>
<bean id="databaseShardingStrategy" class="com.dangdang.ddframe.rdb.sharding.api.strategy.database.DatabaseShardingStrategy">
<constructor-arg index="0" value="user_id"/>
<constructor-arg index="1">
<bean class="com.ccy.algorithm.SingleKeyModuloDatabaseShardingAlgorithm" />
</constructor-arg>
</bean>
<bean id="tableShardingStrategy" class="com.dangdang.ddframe.rdb.sharding.api.strategy.table.TableShardingStrategy">
<constructor-arg index="0" value="order_id"/>
<constructor-arg index="1">
<bean class="com.ccy.algorithm.SingleKeyModuloTableShardingAlgorithm" />
</constructor-arg>
</bean>
<bean id="shardingRule" class="com.dangdang.ddframe.rdb.sharding.api.rule.ShardingRule">
<constructor-arg index="0" ref="dataSourceRule"/>
<constructor-arg index="1">
<list>
<ref bean="orderTableRule"/>
</list>
</constructor-arg>
<constructor-arg index="2" ref="databaseShardingStrategy"/>
<constructor-arg index="3" ref="tableShardingStrategy"/>
</bean>
<!--sharding数据源-->
<bean id="shardingDataSource" class="com.dangdang.ddframe.rdb.sharding.api.ShardingDataSource">
<constructor-arg ref="shardingRule"/>
</bean>
<!-- 4.配置SqlSessionFactory 整合mybatis，自动扫描mapper文件 -->
<!-- sqlSessionFactory -->
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<!-- 数据库连接池 -->
<property name="dataSource" ref="shardingDataSource" />
<!-- 加载mybatis的全局配置文件 -->
<property name="configLocation" value="classpath:sqlMapConfig.xml" />
</bean>
<!-- mapper扫描器 -->
<!-- mapper批量扫描，从mapper包中扫描出mapper接口，自动创建代理对象并且在spring容器中注入
遵循规范:将mapper.java和mapper.xml映射文件名称保持一致，且在一个目录中.
自动扫描出来的mapper的bean的id为mapper类名(首字母小写)-->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<!-- 扫描包路径，如果需要扫描多个包，中间使用半角逗号隔开 -->
<property name="basePackage" value="com.ccy.dao"></property>
<property name="sqlSessionFactoryBeanName" value="sqlSessionFactory" />
</bean>
<!-- 5.配置事务 -->
<bean id="txManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="shardingDataSource"/>
</bean>
<tx:advice id="txAdvice" transaction-manager="txManager">
<tx:attributes>
<tx:method name="insert*" propagation="REQUIRED"/>
<tx:method name="update*" propagation="REQUIRED"/>
<tx:method name="delete*" propagation="REQUIRED"/>
<tx:method name="find*" read-only="true"/>
<tx:method name="get*" read-only="true"/>
<tx:method name="view*" read-only="true"/>
</tx:attributes>
</tx:advice>
<aop:config>
<aop:pointcut expression="execution(* com.ccy.services.*.*(..))" id="txPointCut"/>
<aop:advisor advice-ref="txAdvice" pointcut-ref="txPointCut"/>
</aop:config>
</beans>5.使用感受
暂时不支持spring配置和动态表配置，使用起来确实不太方便，希望当当的小伙伴们赶紧实现制定的未来线路规划
ps:更多数据库切分知识链接直达：http://blog.csdn.net/column/details/sharding.html （来自Laurence的技术博客）
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来源：CSDN
作者：caicongyang
链接：https://blog.csdn.net/caicongyang/article/details/50784179