关于数据库:ShardingSphere-4x-ShardingJDBC-用户手册之数据分片使用手册

不应用 Spring

引入 Maven 依赖

<dependency>
    <groupId>org.apache.shardingsphere</groupId>
    <artifactId>sharding-jdbc-core</artifactId>
    <version>${sharding-sphere.version}</version>
</dependency>

基于 Java 编码的规定配置

Sharding-JDBC 的分库分表通过规定配置形容，以下例子是依据 user_id 取模分库, 且依据 order_id 取模分表的两库两表的配置。

    // 配置实在数据源
    Map<String, DataSource> dataSourceMap = new HashMap<>();
    
    // 配置第一个数据源
    BasicDataSource dataSource1 = new BasicDataSource();
    dataSource1.setDriverClassName("com.mysql.jdbc.Driver");
    dataSource1.setUrl("jdbc:mysql://localhost:3306/ds0");
    dataSource1.setUsername("root");
    dataSource1.setPassword("");
    dataSourceMap.put("ds0", dataSource1);
    
    // 配置第二个数据源
    BasicDataSource dataSource2 = new BasicDataSource();
    dataSource2.setDriverClassName("com.mysql.jdbc.Driver");
    dataSource2.setUrl("jdbc:mysql://localhost:3306/ds1");
    dataSource2.setUsername("root");
    dataSource2.setPassword("");
    dataSourceMap.put("ds1", dataSource2);
    
    // 配置 Order 表规定
    TableRuleConfiguration orderTableRuleConfig = new TableRuleConfiguration("t_order","ds${0..1}.t_order${0..1}");
    
    // 配置分库 + 分表策略
    orderTableRuleConfig.setDatabaseShardingStrategyConfig(new InlineShardingStrategyConfiguration("user_id", "ds${user_id % 2}"));
    orderTableRuleConfig.setTableShardingStrategyConfig(new InlineShardingStrategyConfiguration("order_id", "t_order${order_id % 2}"));
    
    // 配置分片规定
    ShardingRuleConfiguration shardingRuleConfig = new ShardingRuleConfiguration();
    shardingRuleConfig.getTableRuleConfigs().add(orderTableRuleConfig);
    
    // 省略配置 order_item 表规定...
    // ...
    
    // 获取数据源对象
    DataSource dataSource = ShardingDataSourceFactory.createDataSource(dataSourceMap, shardingRuleConfig, new Properties());

基于 Yaml 的规定配置

或通过 Yaml 形式配置，与以上配置等价：

dataSources:
  ds0: !!org.apache.commons.dbcp.BasicDataSource
    driverClassName: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/ds0
    username: root
    password: 
  ds1: !!org.apache.commons.dbcp.BasicDataSource
    driverClassName: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/ds1
    username: root
    password: 
    
shardingRule:
  tables:
    t_order: 
      actualDataNodes: ds${0..1}.t_order${0..1}
      databaseStrategy: 
        inline:
          shardingColumn: user_id
          algorithmExpression: ds${user_id % 2}
      tableStrategy: 
        inline:
          shardingColumn: order_id
          algorithmExpression: t_order${order_id % 2}
    t_order_item: 
      actualDataNodes: ds${0..1}.t_order_item${0..1}
      databaseStrategy: 
        inline:
          shardingColumn: user_id
          algorithmExpression: ds${user_id % 2}
      tableStrategy: 
        inline:
          shardingColumn: order_id
          algorithmExpression: t_order_item${order_id % 2}

    DataSource dataSource = YamlShardingDataSourceFactory.createDataSource(yamlFile);

应用原生 JDBC

通过 ShardingDataSourceFactory 或者 YamlShardingDataSourceFactory 工厂和规定配置对象获取 ShardingDataSource，ShardingDataSource 实现自 JDBC 的标准接口 DataSource。而后可通过 DataSource 抉择应用原生 JDBC 开发，或者应用 JPA, MyBatis 等 ORM 工具。
以 JDBC 原生实现为例：

DataSource dataSource = YamlShardingDataSourceFactory.createDataSource(yamlFile);
String sql = "SELECT i.* FROM t_order o JOIN t_order_item i ON o.order_id=i.order_id WHERE o.user_id=? AND o.order_id=?";
try (Connection conn = dataSource.getConnection();
        PreparedStatement preparedStatement = conn.prepareStatement(sql)) {preparedStatement.setInt(1, 10);
    preparedStatement.setInt(2, 1001);
    try (ResultSet rs = preparedStatement.executeQuery()) {while(rs.next()) {System.out.println(rs.getInt(1));
            System.out.println(rs.getInt(2));
        }
    }
}

应用 Spring

引入 Maven 依赖

<!-- for spring boot -->
<dependency>
    <groupId>org.apache.shardingsphere</groupId>
    <artifactId>sharding-jdbc-spring-boot-starter</artifactId>
    <version>${sharding-sphere.version}</version>
</dependency>

<!-- for spring namespace -->
<dependency>
    <groupId>org.apache.shardingsphere</groupId>
    <artifactId>sharding-jdbc-spring-namespace</artifactId>
    <version>${sharding-sphere.version}</version>
</dependency>

基于 Spring boot 的规定配置

spring.shardingsphere.datasource.names=ds0,ds1

spring.shardingsphere.datasource.ds0.type=org.apache.commons.dbcp2.BasicDataSource
spring.shardingsphere.datasource.ds0.driver-class-name=com.mysql.jdbc.Driver
spring.shardingsphere.datasource.ds0.url=jdbc:mysql://localhost:3306/ds0
spring.shardingsphere.datasource.ds0.username=root
spring.shardingsphere.datasource.ds0.password=

spring.shardingsphere.datasource.ds1.type=org.apache.commons.dbcp2.BasicDataSource
spring.shardingsphere.datasource.ds1.driver-class-name=com.mysql.jdbc.Driver
spring.shardingsphere.datasource.ds1.url=jdbc:mysql://localhost:3306/ds1
spring.shardingsphere.datasource.ds1.username=root
spring.shardingsphere.datasource.ds1.password=

spring.shardingsphere.sharding.default-database-strategy.inline.sharding-column=user_id
spring.shardingsphere.sharding.default-database-strategy.inline.algorithm-expression=ds$->{user_id % 2}

spring.shardingsphere.sharding.tables.t_order.actual-data-nodes=ds$->{0..1}.t_order$->{0..1}
spring.shardingsphere.sharding.tables.t_order.table-strategy.inline.sharding-column=order_id
spring.shardingsphere.sharding.tables.t_order.table-strategy.inline.algorithm-expression=t_order$->{order_id % 2}

spring.shardingsphere.sharding.tables.t_order_item.actual-data-nodes=ds$->{0..1}.t_order_item$->{0..1}
spring.shardingsphere.sharding.tables.t_order_item.table-strategy.inline.sharding-column=order_id
spring.shardingsphere.sharding.tables.t_order_item.table-strategy.inline.algorithm-expression=t_order_item$->{order_id % 2}

基于 Spring boot + JNDI 的规定配置

如果您打算应用 Spring boot + JNDI 的形式，在利用容器（如 Tomcat）中应用 Sharding-JDBC 时，可应用 spring.shardingsphere.datasource.${datasourceName}.jndiName 来代替数据源的一系列配置。
如：

spring.shardingsphere.datasource.names=ds0,ds1

spring.shardingsphere.datasource.ds0.jndi-name=java:comp/env/jdbc/ds0
spring.shardingsphere.datasource.ds1.jndi-name=jdbc/ds1

spring.shardingsphere.sharding.default-database-strategy.inline.sharding-column=user_id
spring.shardingsphere.sharding.default-database-strategy.inline.algorithm-expression=ds$->{user_id % 2}

spring.shardingsphere.sharding.tables.t_order.actual-data-nodes=ds$->{0..1}.t_order$->{0..1}
spring.shardingsphere.sharding.tables.t_order.table-strategy.inline.sharding-column=order_id
spring.shardingsphere.sharding.tables.t_order.table-strategy.inline.algorithm-expression=t_order$->{order_id % 2}

spring.shardingsphere.sharding.tables.t_order_item.actual-data-nodes=ds$->{0..1}.t_order_item$->{0..1}
spring.shardingsphere.sharding.tables.t_order_item.table-strategy.inline.sharding-column=order_id
spring.shardingsphere.sharding.tables.t_order_item.table-strategy.inline.algorithm-expression=t_order_item$->{order_id % 2}

基于 Spring 命名空间的规定配置

<?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: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://shardingsphere.apache.org/schema/shardingsphere/sharding 
                        http://shardingsphere.apache.org/schema/shardingsphere/sharding/sharding.xsd 
                        ">
    <bean id="ds0" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
        <property name="driverClassName" value="com.mysql.jdbc.Driver" />
        <property name="url" value="jdbc:mysql://localhost:3306/ds0" />
        <property name="username" value="root" />
        <property name="password" value="" />
    </bean>
    <bean id="ds1" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
        <property name="driverClassName" value="com.mysql.jdbc.Driver" />
        <property name="url" value="jdbc:mysql://localhost:3306/ds1" />
        <property name="username" value="root" />
        <property name="password" value="" />
    </bean>
    
    <sharding:inline-strategy id="databaseStrategy" sharding-column="user_id" algorithm-expression="ds$->{user_id % 2}" />
    <sharding:inline-strategy id="orderTableStrategy" sharding-column="order_id" algorithm-expression="t_order$->{order_id % 2}" />
    <sharding:inline-strategy id="orderItemTableStrategy" sharding-column="order_id" algorithm-expression="t_order_item$->{order_id % 2}" />
    
    <sharding:data-source id="shardingDataSource">
        <sharding:sharding-rule data-source-names="ds0,ds1">
            <sharding:table-rules>
                <sharding:table-rule logic-table="t_order" actual-data-nodes="ds$->{0..1}.t_order$->{0..1}" database-strategy-ref="databaseStrategy" table-strategy-ref="orderTableStrategy" />
                <sharding:table-rule logic-table="t_order_item" actual-data-nodes="ds$->{0..1}.t_order_item$->{0..1}" database-strategy-ref="databaseStrategy" table-strategy-ref="orderItemTableStrategy" />
            </sharding:table-rules>
        </sharding:sharding-rule>
    </sharding:data-source>
</beans>

在 Spring 中应用 DataSource

间接通过注入的形式即可应用 DataSource，或者将 DataSource 配置在 JPA、Hibernate 或 MyBatis 中应用。

@Resource
private DataSource dataSource;

规定配置包含数据源配置、表规定配置、分库策略和分表策略组成。这只是最简略的配置形式，理论应用可更加灵便，如：多分片键，分片策略间接和表规定配置绑定等。更多的具体配置请参考配置手册。