1 Maven依赖

2 配置文件

3 Controller

4 Service

5 Model

6 Mapper

7 运行结果

ShardingSphere是一款开源的支持分库分表的数据库中间件，其由三部分组成：

Sharding-JDBC：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。
Sharding-Proxy：定位为透明化的数据库代理端，提供封装了数据库二进制协议的服务端版本，用于完成对异构语言的支持。目前先提供MySQL/PostgreSQL版本，它可以使用任何兼容MySQL/PostgreSQL协议的访问客户端(如：MySQL Command Client, MySQL Workbench, Navicat等)操作数据，对DBA更加友好。
Sharding-Sidecar（规划中）：定位为Kubernetes的云原生数据库代理，以Sidecar的形式代理所有对数据库的访问。通过无中心、零侵入的方案提供与数据库交互的的啮合层，即Database Mesh，又可称数据网格。

本文对Sharding-JDBC做一个简单的模拟分库分表的使用，完整的使用请参看官方文档。

这里模拟两个数据库test1和test2，分别有两张t_order和两张t_order_item表，如下所示：

1 Maven依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.6.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.hys</groupId>
    <artifactId>sharding-jdbc-demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>sharding-jdbc-demo</name>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.2</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.apache.shardingsphere</groupId>
            <artifactId>sharding-jdbc-spring-boot-starter</artifactId>
            <version>4.0.1</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

2 配置文件

#配置ds0和ds1两个数据源
spring.shardingsphere.datasource.names=ds0,ds1
#ds0配置
spring.shardingsphere.datasource.ds0.type=com.zaxxer.hikari.HikariDataSource
spring.shardingsphere.datasource.ds0.driver-class-name=com.mysql.jdbc.Driver
spring.shardingsphere.datasource.ds0.jdbc-url=jdbc:mysql://127.0.0.1:3306/test1?serverTimezone=GMT%2B8&useSSL=false&useUnicode=true&characterEncoding=UTF-8
spring.shardingsphere.datasource.ds0.username=root
spring.shardingsphere.datasource.ds0.password=root
#ds1配置
spring.shardingsphere.datasource.ds1.type=com.zaxxer.hikari.HikariDataSource
spring.shardingsphere.datasource.ds1.driver-class-name=com.mysql.jdbc.Driver
spring.shardingsphere.datasource.ds1.jdbc-url=jdbc:mysql://127.0.0.1:3306/test2?serverTimezone=GMT%2B8&useSSL=false&useUnicode=true&characterEncoding=UTF-8
spring.shardingsphere.datasource.ds1.username=root
spring.shardingsphere.datasource.ds1.password=root
#分库策略，根据id取模确定数据进哪个数据库
spring.shardingsphere.sharding.default-database-strategy.inline.sharding-column=user_id
spring.shardingsphere.sharding.default-database-strategy.inline.algorithm-expression=ds$->{user_id % 2}
#绑定表
spring.shardingsphere.sharding.binding-tables=t_order,t_order_item
#具体分表策略
#节点ds0.t_order_0,ds0.t_order_1,ds1.t_order_0,ds1.t_order_1
spring.shardingsphere.sharding.tables.t_order.actual-data-nodes=ds$->{0..1}.t_order_$->{0..1}
#分表字段id
spring.shardingsphere.sharding.tables.t_order.table-strategy.inline.sharding-column=order_id
#分表策略，根据id取模,确定数据最终落在那个表中
spring.shardingsphere.sharding.tables.t_order.table-strategy.inline.algorithm-expression=t_order_$->{order_id % 2}
#使用SNOWFLAKE算法生成主键
spring.shardingsphere.sharding.tables.t_order.key-generator.column=order_id
spring.shardingsphere.sharding.tables.t_order.key-generator.type=SNOWFLAKE
#节点ds0.t_order_item_0,ds0.t_order_item_1,ds1.t_order_item_0,ds1.t_order_item_1
spring.shardingsphere.sharding.tables.t_order_item.actual-data-nodes=ds$->{0..1}.t_order_item_$->{0..1}
#分表字段id
spring.shardingsphere.sharding.tables.t_order_item.table-strategy.inline.sharding-column=order_id
#分表策略，根据id取模,确定数据最终落在那个表中
spring.shardingsphere.sharding.tables.t_order_item.table-strategy.inline.algorithm-expression=t_order_item_$->{order_id % 2}
#使用SNOWFLAKE算法生成主键
spring.shardingsphere.sharding.tables.t_order_item.key-generator.column=order_item_id
spring.shardingsphere.sharding.tables.t_order_item.key-generator.type=SNOWFLAKE

3 Controller

import com.hys.shardingjdbc.demo.service.OrderService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * 订单
 *
 * @author Robert Hou
 * @date 2020年05月01日 14:51
 **/
@RestController
public class OrderController {

    @Autowired
    private OrderService orderService;

    @GetMapping("confirm_order")
    public String confirmOrder(Integer sequenceId) {
        long id = orderService.confirmOrder(sequenceId);
        return "创建订单成功:订单ID = " + id;
    }
}

4 Service

/**
 * 订单
 *
 * @author Robert Hou
 * @date 2020年05月01日 14:48
 **/
public interface OrderService {

    long confirmOrder(int sequenceId);
}

import com.hys.shardingjdbc.demo.mapper.OrderItemMapper;
import com.hys.shardingjdbc.demo.mapper.OrderMapper;
import com.hys.shardingjdbc.demo.model.Order;
import com.hys.shardingjdbc.demo.model.OrderItem;
import com.hys.shardingjdbc.demo.service.OrderService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.sql.SQLException;

/**
 * 订单
 *
 * @author Robert Hou
 * @date 2020年05月01日 14:48
 **/
@Service
public class OrderServiceImpl implements OrderService {

    @Autowired
    private OrderMapper orderMapper;
    @Autowired
    private OrderItemMapper orderItemMapper;

    @Override
    public long confirmOrder(int sequenceId) {
        //创建订单
        Order order = new Order();
        order.setAddressId(sequenceId);
        order.setUserId(sequenceId);
        order.setStatus("创建订单");
        orderMapper.insert(order);
        //订单对应产品
        OrderItem item = new OrderItem();
        item.setOrderId(order.getOrderId());
        item.setUserId(sequenceId);
        item.setOrderItemId(sequenceId);
        item.setStatus("创建订单");
        orderItemMapper.insert(item);
        return order.getOrderId();
    }
}

5 Model

import lombok.Data;
import lombok.NoArgsConstructor;

import java.io.Serializable;

/**
 * 订单
 *
 * @author Robert Hou
 * @date 2020年05月01日 14:42
 **/
@Data
@NoArgsConstructor
public class Order implements Serializable {

    private static final long serialVersionUID = -3963571151434932747L;

    private long orderId;

    private int userId;

    private long addressId;

    private String status;
}

import lombok.Data;
import lombok.NoArgsConstructor;

import java.io.Serializable;

/**
 * 订单项
 *
 * @author Robert Hou
 * @date 2020年05月01日 14:46
 **/
@Data
@NoArgsConstructor
public class OrderItem implements Serializable {

    private static final long serialVersionUID = -7096145519089736408L;

    private long orderItemId;

    private long orderId;

    private int userId;

    private String status;
}

6 Mapper

import com.hys.shardingjdbc.demo.model.Order;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Options;

import java.sql.SQLException;

/**
 * 订单
 *
 * @author Robert Hou
 * @date 2020年05月01日 14:41
 **/
@Mapper
public interface OrderMapper {

    @Options(useGeneratedKeys = true, keyProperty = "orderId", keyColumn = "order_id")
    @Insert("INSERT INTO t_order (user_id, address_id, status) VALUES (#{userId,jdbcType=INTEGER}, #{addressId,jdbcType=BIGINT}, #{status,jdbcType=VARCHAR})")
    long insert(Order order);
}

import com.hys.shardingjdbc.demo.model.OrderItem;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Options;

import java.sql.SQLException;

/**
 * 订单项
 *
 * @author Robert Hou
 * @date 2020年05月01日 14:46
 **/
@Mapper
public interface OrderItemMapper {

    @Options(useGeneratedKeys = true, keyProperty = "orderItemId", keyColumn = "order_item_id")
    @Insert("INSERT INTO t_order_item (order_id, user_id, status) VALUES (#{orderId,jdbcType=INTEGER}, #{userId,jdbcType=INTEGER}, #{status,jdbcType=VARCHAR})")
    long insert(OrderItem order);
}

7 运行结果

当启动完项目后，可以在日志中看到打印了分库分表的信息：

bindingTables:
- t_order
- t_order_item
defaultDatabaseStrategy:
  inline:
    algorithmExpression: ds$->{user_id % 2}
    shardingColumn: user_id
tables:
  t_order:
    actualDataNodes: ds$->{0..1}.t_order_$->{0..1}
    keyGenerator:
      column: order_id
      type: SNOWFLAKE
    logicTable: t_order
    tableStrategy:
      inline:
        algorithmExpression: t_order_$->{order_id % 2}
        shardingColumn: order_id
  t_order_item:
    actualDataNodes: ds$->{0..1}.t_order_item_$->{0..1}
    keyGenerator:
      column: order_item_id
      type: SNOWFLAKE
    logicTable: t_order_item
    tableStrategy:
      inline:
        algorithmExpression: t_order_item_$->{order_id % 2}
        shardingColumn: order_id

接着输入http://localhost:8080/confirm_order?sequenceId=1和http://localhost:8080/confirm_order?sequenceId=2，随后查看数据库，可以看到分库分表成功：

Sharding-JDBC概述

1 Maven依赖

2 配置文件

3 Controller

4 Service

5 Model

6 Mapper

7 运行结果

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