Sharding

Background

The configuration method of data sharding Spring Namespace is applicable to traditional Spring projects. The sharding rules and attributes are configured through the namespace xml configuration file. Spring completes the creation and management of ShardingSphereDataSource objects to avoid additional coding work.

Parameters

Namespace: http://shardingsphere.apache.org/schema/shardingsphere/sharding/sharding-5.2.1.xsd

<sharding:rule />

<sharding:table-rule />

<sharding:binding-table-rules />

<sharding:binding-table-rule />

<sharding:broadcast-table-rules />

<sharding:broadcast-table-rule />

<sharding:standard-strategy />

<sharding:complex-strategy />

<sharding:hint-strategy />

<sharding:none-strategy />

<sharding:key-generate-strategy />

<sharding:audit-strategy />

<sharding:auditors />

<sharding:auditor />

<sharding:sharding-algorithm />

<sharding:key-generate-algorithm />

<sharding:audit-algorithm />

Please refer to Built-in Sharding Audit Algorithm List, Built-in Key Generate Algorithm List and Built-in Sharding Audit Algorithm List for more details about type of algorithm.

Attention: Inline expression identifier can use ${...} or $->{...}, but ${...} is conflict with spring placeholder of properties, so use $->{...} on spring environment is better.

Procedure

1. Configure data sharding rules in the Spring Namespace configuration file, including data source, sharding rules, global attributes and other configuration items.
2. Start the Spring program, the configuration will be loaded automatically, and the ShardingSphereDataSource will be initialized.

Sample

<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:shardingsphere="http://shardingsphere.apache.org/schema/shardingsphere/datasource"
       xmlns:sharding="http://shardingsphere.apache.org/schema/shardingsphere/sharding"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
                           http://www.springframework.org/schema/beans/spring-beans.xsd 
                           http://www.springframework.org/schema/tx 
                           http://www.springframework.org/schema/tx/spring-tx.xsd
                           http://www.springframework.org/schema/context 
                           http://www.springframework.org/schema/context/spring-context.xsd
                           http://shardingsphere.apache.org/schema/shardingsphere/datasource
                           http://shardingsphere.apache.org/schema/shardingsphere/datasource/datasource.xsd
                           http://shardingsphere.apache.org/schema/shardingsphere/sharding
                           http://shardingsphere.apache.org/schema/shardingsphere/sharding/sharding.xsd
                           ">
    <context:component-scan base-package="org.apache.shardingsphere.example.core.mybatis" />
    <bean id="demo_ds_0" class="com.zaxxer.hikari.HikariDataSource" destroy-method="close">
        <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
        <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/demo_ds_0?serverTimezone=UTC&amp;useSSL=false&amp;useUnicode=true&amp;characterEncoding=UTF-8"/>
        <property name="username" value="root"/>
        <property name="password" value=""/>
    </bean>
    <bean id="demo_ds_1" class="com.zaxxer.hikari.HikariDataSource" destroy-method="close">
        <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
        <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/demo_ds_1?serverTimezone=UTC&amp;useSSL=false&amp;useUnicode=true&amp;characterEncoding=UTF-8"/>
        <property name="username" value="root"/>
        <property name="password" value=""/>
    </bean>
    <sharding:standard-strategy id="databaseStrategy" sharding-column="user_id" algorithm-ref="inlineStrategyShardingAlgorithm" />
    <sharding:sharding-algorithm id="inlineStrategyShardingAlgorithm" type="INLINE">
        <props>
            <prop key="algorithm-expression">demo_ds_${user_id % 2}</prop>
        </props>
    </sharding:sharding-algorithm>
    <sharding:key-generate-algorithm id="snowflakeAlgorithm" type="SNOWFLAKE">
    </sharding:key-generate-algorithm>
    <sharding:audit-algorithm id="auditAlgorithm" type="DML_SHARDING_CONDITIONS" />
    <sharding:key-generate-strategy id="orderKeyGenerator" column="order_id" algorithm-ref="snowflakeAlgorithm" />
    <sharding:key-generate-strategy id="itemKeyGenerator" column="order_item_id" algorithm-ref="snowflakeAlgorithm" />
    <sharding:audit-strategy id="defaultAudit" allow-hint-disable="true">
        <sharding:auditors>
            <sharding:auditor algorithm-ref="auditAlgorithm" />
        </sharding:auditors>
    </sharding:audit-strategy>
    <sharding:audit-strategy id="shardingKeyAudit" allow-hint-disable="true">
        <sharding:auditors>
            <sharding:auditor algorithm-ref="auditAlgorithm" />
        </sharding:auditors>
    </sharding:audit-strategy>
    <sharding:rule id="shardingRule">
        <sharding:table-rules>
            <sharding:table-rule logic-table="t_order" database-strategy-ref="databaseStrategy" key-generate-strategy-ref="orderKeyGenerator" audit-strategy-ref="shardingKeyAudit" />
            <sharding:table-rule logic-table="t_order_item" database-strategy-ref="databaseStrategy" key-generate-strategy-ref="itemKeyGenerator" />
        </sharding:table-rules>
        <sharding:binding-table-rules>
            <sharding:binding-table-rule logic-tables="t_order,t_order_item"/>
        </sharding:binding-table-rules>
        <sharding:broadcast-table-rules>
            <sharding:broadcast-table-rule table="t_address"/>
        </sharding:broadcast-table-rules>
    </sharding:rule>
    <shardingsphere:data-source id="shardingDataSource" database-name="sharding-databases" data-source-names="demo_ds_0, demo_ds_1" rule-refs="shardingRule" />
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="shardingDataSource" />
    </bean>
    <tx:annotation-driven />
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="shardingDataSource"/>
        <property name="mapperLocations" value="classpath*:META-INF/mappers/*.xml"/>
    </bean>
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="org.apache.shardingsphere.example.core.mybatis.repository"/>
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
    </bean>
</beans>

Related References

• Core Feature: Data Sharding
• Developer Guide: Data Sharding