ShardingSphere初探1 --Sharding-JDBC

Sharding-JDBC

引入maven依赖:

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

注意将version换为实际的版本号.

简介

Sharding-JDBC是ShardingSphere的第一个产品，也是ShardingSphere的前身。 它定位为轻量级Java框架，在Java的JDBC层提供的额外服务。它使用客户端直连数据库，以jar包形式提供服务，无需额外部署和依赖，可理解为增强版的JDBC驱动，完全兼容JDBC和各种ORM框架。

• 适用于任何基于Java的ORM框架，如：JPA, Hibernate, Mybatis, Spring JDBC Template或直接使用JDBC。
• 基于任何第三方的数据库连接池，如：DBCP, C3P0, BoneCP, Druid, HikariCP等。
• 支持任意实现JDBC规范的数据库。目前支持MySQL，Oracle，SQLServer和PostgreSQL。

对比:

Sharding-JDBC的优势在于对Java应用的友好度.

内部结构

图片解析:

黄色部分

图中黄色部分表示的是Sharding-JDBC的入口API,采用工厂方法的形式提供.

目前有ShardingDataSourceFactory 和 MasterSlaveDataSourceFactory 两个工厂类.

ShardingDataSourceFactory 用于创建分库分表或分库分表+读写分离的JDBC驱动,

MasterSlaveDataSourceFactory用于创建独立使用读写分离的JDBC驱动.

蓝色部分

图中蓝色部分表示的是Sharding-JDBC的配置对象,提供灵活多变的配置方式.

ShardingRuleConfiguration是分库分表配置的核心和入口,它可以包含多个

TableRuleConfiguration 和 MasterSlaveRuleConfiguration .

每一组相同规则分片的表配置一个TableRuleConfiguration. 如果需要分库分表和读写分离共同使用,

每一个读写分离的逻辑库配置一个 MasterSlaveRuleConfiguration .

每个TableRuleConfiguration对应一个ShardingStrategyConfiguration,它有5种实现类可供选择.

* 仅读写分离使用MasterSlaveRuleConfiguration即可.

红色部分

图中红色部分表示的是内部对象,由Sharding-JDBC内部使用,应用开发者无需关注.

Sharding-JDBC通过ShardingRuleConfiguration和MasterSlaveRuleConfiguration生成真正

供ShardingDataSource和MasterSlaveDataSource使用的规则对象.

ShardingDataSource和MasterSlaveDataSource实现了DataSource接口, 是JDBC的完整实现方案.

初始化流程:

1. 配置Configuration对象.

2. 通过Factory对象将Configuration对象转化为Rule对象.

3. 通过Factory对象将Rule对象与DataSource对象装配.

4. Sharding-JDBC使用DataSource对象进行分库.

使用约定

在org.apache.shardingsphere.api和org.apache.shardingsphere.shardingjdbc.api 包中的类是面向用户的API，每次修改都会在release notes中明确声明。 其他包中的类属于内部实现，可能随时进行调整，请勿直接使用。

官方Sharding-JDBC相关使用示例 : https://github.com/apache/incubator-shardingsphere-example

数据分片 什么是数据分片?

首先看不使用Spring的方式:

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编码的规则配置

Sharding-JDBC的分库分表通过规则配置描述, 以下例子是根据user_id取模分库,且根据order_id取模分表的两库两表的配置.

    // 配置真实数据源
    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表规则
    TableRuleConfiguration orderTableRuleConfig = new TableRuleConfiguration();
    orderTableRuleConfig.setLogicTable("t_order");
    orderTableRuleConfig.setActualDataNodes("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}"));

    // 配置分片规则
    ShardingRuleConfiguration shardingRuleConfig = new ShardingRuleConfiguration();
    shardingRuleConfig.getTableRuleConfigs().add(orderTableRuleConfig);

    // 省略配置order_item表规则...
    // ...

    // 获取数据源对象
    DataSource dataSource = ShardingDataSourceFactory.createDataSource(dataSourceMap, shardingRuleConfig, new ConcurrentHashMap(), new Properties());

基于yaml的规则配置:

或通过Yaml方式配置,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
          algorithmInlineExpression: ds${user_id % 2}
      tableStrategy:
        inline:
          shardingColumn: order_id
          algorithmInlineExpression: t_order${order_id % 2}
    t_order_item:
      actualDataNodes: ds${0..1}.t_order_item${0..1}
      databaseStrategy:
        inline:
          shardingColumn: user_id
          algorithmInlineExpression: ds${user_id % 2}
      tableStrategy:
        inline:
          shardingColumn: order_id
          algorithmInlineExpression: t_order_item${order_id % 2}

    DataSource dataSource = YamlShardingDataSourceFactory.createDataSource(yamlFile);

使用原生JDBC:

通过ShardingDataSourceFactory或者YamlShardingDataSourceFactory工厂和规则配置对象获取ShardingDataSource, ShardingDataSource实现自JDBC的

标准接口DataSource. 然后可通过DataSource选择使用原生JDBC开发, 或者使用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));
        }
    }
}

使用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的规则配置

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的规则配置

如果您计划使用Spring boot + JNDI的方式, 在应用容器(如Tomcat)中使用Sharding-JDBC时,可使用

spring.shardingsphere.datasource.${datasourceName}.jndiName来替代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命名空间的规则配置:

<?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中使用DataSource

直接通过注入的方式即可使用DataSource, 或者将DataSource配置在JPA,Hibernate或MyBatis中使用.

@Resource
private DataSource dataSource;

规则配置包括数据源配置,表规则配置,分库策略和分表策略组成.这只是最简单的配置方式,实际使用可更加灵活,

如:多分片键, 分片策略直接和表规则配置绑定等.

读写分离

同样读写分离的也是单独的依赖

不使用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编码的规则配置

    // 配置真实数据源
    Map<String, DataSource> dataSourceMap = new HashMap<>();

    // 配置主库
    BasicDataSource masterDataSource = new BasicDataSource();
    masterDataSource.setDriverClassName("com.mysql.jdbc.Driver");
    masterDataSource.setUrl("jdbc:mysql://localhost:3306/ds_master");
    masterDataSource.setUsername("root");
    masterDataSource.setPassword("");
    dataSourceMap.put("ds_master", masterDataSource);

    // 配置第一个从库
    BasicDataSource slaveDataSource1 = new BasicDataSource();
    slaveDataSource1.setDriverClassName("com.mysql.jdbc.Driver");
    slaveDataSource1.setUrl("jdbc:mysql://localhost:3306/ds_slave0");
    slaveDataSource1.setUsername("root");
    slaveDataSource1.setPassword("");
    dataSourceMap.put("ds_slave0", slaveDataSource1);

    // 配置第二个从库
    BasicDataSource slaveDataSource2 = new BasicDataSource();
    slaveDataSource2.setDriverClassName("com.mysql.jdbc.Driver");
    slaveDataSource2.setUrl("jdbc:mysql://localhost:3306/ds_slave1");
    slaveDataSource2.setUsername("root");
    slaveDataSource2.setPassword("");
    dataSourceMap.put("ds_slave1", slaveDataSource2);

    // 配置读写分离规则
    MasterSlaveRuleConfiguration masterSlaveRuleConfig = new MasterSlaveRuleConfiguration("ds_master_slave", "ds_master", Arrays.asList("ds_slave0", "ds_slave1"));

    // 获取数据源对象
    DataSource dataSource = MasterSlaveDataSourceFactory.createDataSource(createDataSourceMap(), masterSlaveRuleConfig, new HashMap<String, Object>(), new Properties());

基于Yaml的规则配置:

或通过Yaml方式配置,与以上配置等价:

dataSources:
  ds_master: !!org.apache.commons.dbcp.BasicDataSource
    driverClassName: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/ds_master
    username: root
    password:
  ds_slave0: !!org.apache.commons.dbcp.BasicDataSource
    driverClassName: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/ds_slave0
    username: root
    password:
  ds_slave1: !!org.apache.commons.dbcp.BasicDataSource
    driverClassName: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/ds_slave1
    username: root
    password: 

masterSlaveRule:
  name: ds_ms
  masterDataSourceName: ds_master
  slaveDataSourceNames: [ds_slave0, ds_slave1]

props:
  sql.show: true

    DataSource dataSource = MasterSlaveDataSourceFactory.createDataSource(yamlFile);

使用原生JDBC

通过MasterSlaveDataSourceFactory工厂和规则配置对象获取MasterSlaveDataSource, MasterSlaveDataSource实现自JDBC的标准接口DataSource.

然后可通过DataSource选择使用原生JDBC开发,或者使用JPA, MyBatis等ORM工具. 以JDBC原生实现为例:

DataSource dataSource = MasterSlaveDataSourceFactory.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));
        }
    }
}

使用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的规则配置:

spring.shardingsphere.datasource.names=master,slave0,slave1

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

spring.shardingsphere.datasource.slave0.type=org.apache.commons.dbcp.BasicDataSource
spring.shardingsphere.datasource.slave0.driver-class-name=com.mysql.jdbc.Driver
spring.shardingsphere.datasource.slave0.url=jdbc:mysql://localhost:3306/slave0
spring.shardingsphere.datasource.slave0.username=root
spring.shardingsphere.datasource.slave0.password=

spring.shardingsphere.datasource.slave1.type=org.apache.commons.dbcp.BasicDataSource
spring.shardingsphere.datasource.slave1.driver-class-name=com.mysql.jdbc.Driver
spring.shardingsphere.datasource.slave1.url=jdbc:mysql://localhost:3306/slave1
spring.shardingsphere.datasource.slave1.username=root
spring.shardingsphere.datasource.slave1.password=

spring.shardingsphere.masterslave.name=ms
spring.shardingsphere.masterslave.master-data-source-name=master
spring.shardingsphere.masterslave.slave-data-source-names=slave0,slave1

spring.shardingsphere.props.sql.show=true

基于Spring boot + JNDI的规则配置:

如果您计划使用Spring boot + JNDI的方式, 在应用容器(如Tomcat)中使用Sharding-JDBC时,可使用spring.shardingsphere.datasource.${datasourceName}.jndiName来代替数据源的一系列配置.如:

spring.shardingsphere.datasource.names=master,slave0,slave1

spring.shardingsphere.datasource.master.jndi-name=java:comp/env/jdbc/master
spring.shardingsphere.datasource.slave0.jndi-name=jdbc/slave0
spring.shardingsphere.datasource.slave1.jndi-name=jdbc/slave1

spring.shardingsphere.masterslave.name=ms
spring.shardingsphere.masterslave.master-data-source-name=master
spring.shardingsphere.masterslave.slave-data-source-names=slave0,slave1

spring.shardingsphere.props.sql.show=true

基于Spring命名空间的规则配置:

<?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:master-slave="http://shardingsphere.apache.org/schema/shardingsphere/masterslave"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
                        http://www.springframework.org/schema/beans/spring-beans.xsd
                        http://shardingsphere.apache.org/schema/shardingsphere/masterslave
                        http://shardingsphere.apache.org/schema/shardingsphere/masterslave/master-slave.xsd
                        ">
    <bean id="ds_master" 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/ds_master" />
        <property name="username" value="root" />
        <property name="password" value="" />
    </bean>
    <bean id="ds_slave0" 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/ds_slave0" />
        <property name="username" value="root" />
        <property name="password" value="" />
    </bean>
    <bean id="ds_slave1" 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/ds_slave1" />
        <property name="username" value="root" />
        <property name="password" value="" />
    </bean>

    <master-slave:data-source id="masterSlaveDataSource" master-data-source-name="ds_master" slave-data-source-names="ds_slave0, ds_slave1" >
        <master-slave:props>
                <prop key="sql.show">${sql_show}</prop>
                <prop key="executor.size">10</prop>
                <prop key="foo">bar</prop>
            </master-slave:props>
    </master-slave:data-source>
</beans>

在Spring中使用DataSource

直接通过注入的方式即可使用DataSource, 或者将DataSource配置在JPA, Hibernate或MyBatis中使用.

@Resource
private DataSource dataSource;

配置:

配置是整个Sharding-JDBC的核心,是Sharding-JDBC中唯一与应用开发者打交道的模块. 配置模块也是Sharding-JDBC的门户,

通过它可以快速清晰的理解Sharding-JDBC所提供的功能.

本部分是Sharding-JDBC的配置参考手册,需要时可当做字典查阅.

Sharding-JDBC提供了4种配置方式,用于不同的使用场景.通过配置,应用开发者可以灵活的使用分库分表,读写分离以及分库分表+读写分离共用.

强制路由

ShardingSphere使用ThreadLocal管理分片键值进行Hint强制路由. 可以通过编程的方式向HintManager中添加分片值,该分片值仅在当前线程内生效.

Hint方式主要使用场景:

1. 分片字段不存在SQL中, 数据库表结构中, 而存在于外部业务逻辑.

2. 强制在主库进行某些数据操作.

基于暗示(Hint)的数据分片

配置Hint分片算法

Hint分片算法需要用户实现org.apache.shardingsphere.api.sharding.hint.HintShardingAlgorithm接口.

ShardingSphere在进行Routing时,如果发现LogicTable的TableRule采用了Hint的分片算法,将会从HintManager中获取分片值进行路由操作.

参考配置如下:

shardingRule:
  tables:
   t_order:
        actualDataNodes: demo_ds_${0..1}.t_order_${0..1}
        databaseStrategy:
          hint:
            algorithmClassName: org.apache.shardingsphere.userAlgo.HintAlgorithm
        tableStrategy:
          hint:
            algorithmClassName: org.apache.shardingsphere.userAlgo.HintAlgorithm
  defaultTableStrategy:
    none:
  defaultKeyGenerator:
    type: SNOWFLAKE
    column: order_id
  props:
      sql.show: true

获取HintManager

HintManager hintManager = HintManager.getInstance();

添加分片键值

* 使用hintManager.addDatabaseShardingValue来添加数据源分片键值.

* 使用hintManager.addTableShardingValue来添加表分片键值.

分库不分表情况下, 强制路由至某一个分库时, 可使用hintManager.setDatabaseShardingValue方式添加分片.

通过此方式添加分片键值后,将跳过SQL解析和改写阶段, 从而提高整体执行效率.

清除分片键值

分片键值保存存在ThreadLocal中,所以需要在操作结束时调用hintManager.close()来清除ThreadLocal中的内容.

hintManager实现了AutoCloseable接口, 可推荐使用 try with resource 自动关闭.

完整代码示例:

// Sharding database and table with using hintManager.
        String sql = "SELECT * FROM t_order";
        try (HintManager hintManager = HintManager.getInstance();
             Connection conn = dataSource.getConnection();
             PreparedStatement preparedStatement = conn.prepareStatement(sql)) {
            hintManager.addDatabaseShardingValue("t_order", 1);
            hintManager.addTableShardingValue("t_order", 2);
            try (ResultSet rs = preparedStatement.executeQuery()) {
                while (rs.next()) {
                    // ...
                }
            }
        }

// Sharding database without sharding table and routing to only one database with using hintManger.
        String sql = "SELECT * FROM t_order";
        try (HintManager hintManager = HintManager.getInstance();
             Connection conn = dataSource.getConnection();
             PreparedStatement preparedStatement = conn.prepareStatement(sql)) {
            hintManager.setDatabaseShardingValue(3);
            try (ResultSet rs = preparedStatement.executeQuery()) {
                while (rs.next()) {
                    // ...
                }
            }
        }

基于暗示(Hint)的强制主库路由

获取HintManager

与基于暗示(Hint)的数据分片相同.

设置主库路由

* 使用hintManager.setMasterRouteOnly设置主库路由.

清除分片键值

与基于暗示(Hint)的数据分片相同.

完整代码示例:

String sql = "SELECT * FROM t_order";
try (
        HintManager hintManager = HintManager.getInstance();
        Connection conn = dataSource.getConnection();
        PreparedStatement preparedStatement = conn.prepareStatement(sql)) {
    hintManager.setMasterRouteOnly();
    try (ResultSet rs = preparedStatement.executeQuery()) {
        while (rs.next()) {
            // ...
        }
    }
}

编排治理(想起了mooc服务计算与服务生态系统)

使用治理功能需要指定一个注册中心. 配置将全部存入注册中心, 可以在每次启动时使用本地配置覆盖注册中心配置,

也可以只通过注册中心读取配置.

不使用Spring

引入Maven依赖:

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

<!--若使用zookeeper, 请加入下面Maven坐标-->
<dependency>
    <groupId>org.apache.shardingsphere</groupId>
    <artifactId>sharding-orchestration-reg-zookeeper-curator</artifactId>
</dependency>

<!--若使用etcd, 请下面Maven坐标-->
<dependency>
    <groupId>org.apache.shardingsphere</groupId>
    <artifactId>sharding-orchestration-reg-etcd</artifactId>
</dependency>

基于Java编码的规则配置:

    // 省略配置dataSourceMap以及shardingRuleConfig
    // ...

    // 配置注册中心
    RegistryCenterConfiguration regConfig = new RegistryCenterConfiguration();
    regConfig.setServerLists("localhost:2181");
    regConfig.setNamespace("sharding-sphere-orchestration");

    // 配置治理
    OrchestrationConfiguration orchConfig = new OrchestrationConfiguration("orchestration-sharding-data-source", regConfig, false);

    // 获取数据源对象
    DataSource dataSource = OrchestrationShardingDataSourceFactory.createDataSource(dataSourceMap, shardingRuleConfig, new ConcurrentHashMap(), new Properties(), orchConfig);

基于Yaml的规则配置

或通过Yaml方式配置,与以上配置等价:

orchestration:
  name: orchestration-sharding-data-source
  overwrite: false
  registry:
    serverLists: localhost:2181
    namespace: sharding-sphere-orchestration

    DataSource dataSource = YamlOrchestrationShardingDataSourceFactory.createDataSource(yamlFile);

使用Spring

引入Maven依赖:

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

<!--若使用zookeeper, 请加入下面Maven坐标-->
<dependency>
    <groupId>org.apache.shardingsphere</groupId>
    <artifactId>sharding-orchestration-reg-zookeeper-curator</artifactId>
    <version>${sharding-sphere.version}</version>
</dependency>

<!--若使用etcd, 请加入下面Maven坐标-->
<dependency>
    <groupId>org.apache.shardingsphere</groupId>
    <artifactId>sharding-orchestration-reg-etcd</artifactId>
    <version>${sharding-sphere.version}</version>
</dependency>

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

<!--若使用zookeeper, 请加入下面Maven坐标-->
<dependency>
    <groupId>org.apache.shardingsphere</groupId>
    <artifactId>sharding-orchestration-reg-zookeeper-curator</artifactId>
    <version>${sharding-sphere.version}</version>
</dependency>

<!--若使用etcd, 请加入下面Maven坐标-->
<dependency>
    <groupId>org.apache.shardingsphere</groupId>
    <artifactId>sharding-orchestration-reg-etcd</artifactId>
    <version>${sharding-sphere.version}</version>
</dependency>

基于Spring boot的规则配置

spring.shardingsphere.orchestration.name=orchestration-sharding-data-source
spring.shardingsphere.orchestration.overwrite=false
spring.shardingsphere.orchestration.registry.server-lists=localhost:2181
spring.shardingsphere.orchestration.registry.namespace=sharding-jdbc-orchestration

基于Spring命名空间的规则配置:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:orchestraion="http://shardingsphere.apache.org/schema/shardingsphere/orchestration"
       xmlns="http://www.springframework.org/schema/beans"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
                           http://www.springframework.org/schema/beans/spring-beans.xsd
                           http://shardingsphere.apache.org/schema/shardingsphere/orchestration
                           http://shardingsphere.apache.org/schema/shardingsphere/orchestration/orchestration.xsd">
     <import resource="namespace/shardingDataSourceNamespace.xml" />
     <orchestraion:registry-center id="regCenter" server-lists="localhost:3181" namespace="orchestration-spring-namespace-test" operation-timeout-milliseconds="1000" max-retries="3" />
     <orchestraion:sharding-data-source id="simpleShardingOrchestration" data-source-ref="simpleShardingDataSource" registry-center-ref="regCenter" />
</beans>

分布式事务

两阶段提交-XA

引入Maven依赖

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

XA事务管理器将以SPI的方式被Sharding-JDBC所加载.

Atomikos参数配置(可选)

ShardingSphere默认的XA事务管理器为Atomikos, 在项目的logs目录中会生成 xa_tx.log,

这是XA崩溃恢复时所需的日志,请勿删除.

也可以通过在项目的classpath中添加 jta.properties 来订制化Atomikos配置项.

第三方BASE实现-Saga

目前Apache/incubator-shardingsphere暂无BASE事务的实现,但是仍然可以使用第三方实现的Saga事务.

https://shardingsphere.apache.org/document/current/cn/manual/sharding-jdbc/usage/transaction/