shardingsphere5.x整合springboot分库分表实战

官方文档不同版本配置变更记录：Spring Boot Start 配置 :: ShardingSphere

pom.xml配置：

	org.apache.shardingsphere
	shardingsphere-jdbc-core-spring-boot-starter
	5.1.1




	com.baomidou
	mybatis-plus-boot-starter
	3.4.0

建表sql：

CREATE TABLE `orders_0` (
  `id` bigint NOT NULL COMMENT '主键',
  `order_no` varchar(255) NOT NULL COMMENT '订单号',
  `user_id` bigint NOT NULL COMMENT '用户id',
  `pay_amount` decimal(20,2) NOT NULL DEFAULT '0' COMMENT '支付金额',
  `order_status` int NOT NULL COMMENT '订单状态 1-已预约 2-已取车 3-已还车 4-已取消',
  `pay_status` int NOT NULL DEFAULT '0' COMMENT '支付状态 0-未支付 1-支付成功',
  `pay_method` int DEFAULT NULL COMMENT '支付方式 1-微信 2-支付宝',
  `pay_time` timestamp NULL DEFAULT CURRENT_TIMESTAMP COMMENT '支付时间',
  `created_at` timestamp NULL DEFAULT CURRENT_TIMESTAMP COMMENT '创建时间',
  `updated_at` timestamp NULL DEFAULT CURRENT_TIMESTAMP COMMENT '更新时间',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;


CREATE TABLE `orders_1` (
  `id` bigint NOT NULL COMMENT '主键',
  `order_no` varchar(255) NOT NULL COMMENT '订单号',
  `user_id` bigint NOT NULL COMMENT '用户id',
  `pay_amount` decimal(20,2) NOT NULL DEFAULT '0' COMMENT '支付金额',
  `order_status` int NOT NULL COMMENT '订单状态 1-已预约 2-已取车 3-已还车 4-已取消',
  `pay_status` int NOT NULL DEFAULT '0' COMMENT '支付状态 0-未支付 1-支付成功',
  `pay_method` int DEFAULT NULL COMMENT '支付方式 1-微信 2-支付宝',
  `pay_time` timestamp NULL DEFAULT CURRENT_TIMESTAMP COMMENT '支付时间',
  `created_at` timestamp NULL DEFAULT CURRENT_TIMESTAMP COMMENT '创建时间',
  `updated_at` timestamp NULL DEFAULT CURRENT_TIMESTAMP COMMENT '更新时间',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;

......

CREATE TABLE `orders_9` (
  `id` bigint NOT NULL COMMENT '主键',
  `order_no` varchar(255) NOT NULL COMMENT '订单号',
  `user_id` bigint NOT NULL COMMENT '用户id',
  `pay_amount` decimal(20,2) NOT NULL DEFAULT '0' COMMENT '支付金额',
  `order_status` int NOT NULL COMMENT '订单状态 1-已预约 2-已取车 3-已还车 4-已取消',
  `pay_status` int NOT NULL DEFAULT '0' COMMENT '支付状态 0-未支付 1-支付成功',
  `pay_method` int DEFAULT NULL COMMENT '支付方式 1-微信 2-支付宝',
  `pay_time` timestamp NULL DEFAULT CURRENT_TIMESTAMP COMMENT '支付时间',
  `created_at` timestamp NULL DEFAULT CURRENT_TIMESTAMP COMMENT '创建时间',
  `updated_at` timestamp NULL DEFAULT CURRENT_TIMESTAMP COMMENT '更新时间',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;

yml配置：

spring:
  shardingsphere:
    datasource:
      common:
        driver-class-name: com.mysql.jdbc.Driver
        type: com.alibaba.druid.pool.DruidDataSource
      names: db0,db1
      db0:
        url: jdbc:mysql://localhost:3306/test
        username: root
        password: root
        type: com.alibaba.druid.pool.DruidDataSource
      db1:
        url: jdbc:mysql://localhost:3306/zkq_oms_test?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=true&serverTimezone=GMT%2B8
        username: root
        password: root
        type: com.alibaba.druid.pool.DruidDataSource
    # 默认数据源，未分片的表默认执行库
    sharding:
        default-data-source-name: db1
    rules:
     sharding:
        key-generators:
          # 此处必须要配置，否则会导致报错，因为shardingsphere-jdbc-core-spring-boot-starter需要加载此项配置，官网的demo例子有错
          # 分布式序列算法：https://shardingsphere.apache.org/document/current/cn/user-manual/common-config/builtin-algorithm/keygen/
          snowflake:
            type: SNOWFLAKE
            props:
              # 在单机模式下支持用户自定义配置，如果用户不配置使用默认值为0。
              # 在集群模式下会由系统自动生成，相同的命名空间下不会生成重复的值。
              worker-id: 0
        sharding-algorithms:
          # 分片算法：https://shardingsphere.apache.org/document/current/cn/user-manual/common-config/builtin-algorithm/sharding/
          table-mod:
            # 取模类型分片键的值必须是数字，否则会报错
            type: MOD
            props:
              sharding-count: 10
        tables:
          orders:
            # 配置逻辑表:orders与真实库表的对应规则
            actual-data-nodes: db0.orders_$->{0..9}
            # 配置分表规则
            table-strategy:
              standard:
                sharding-column: order_no
                sharding-algorithm-name: table-mod
    enabled: true
    # 展示修改以后的sql语句
    props:
      sql-show: true


mybatis:
    configuration:
        map-underscore-to-camel-case: true
        log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
    type-aliases-package: com.example.demo.entity
    mapper-locations: classpath:mapper/*.xml

orders对象实体：

package com.example.demo.entity;


import com.baomidou.mybatisplus.annotation.TableId;
import lombok.Data;

import java.io.Serializable;
import java.math.BigDecimal;
import java.util.Date;

@Data
public class Orders implements Serializable {
    
    @TableId
    private Long id;

    /**
     * 订单号
     */
    private String orderNo;

    /**
     * 用户id
     */
    private Long userId;

    /**
     * 订单状态 1-已预约 2-已取车 3-已还车 4-已取消
     */
    private Integer orderStatus;

    /**
     * 支付状态 0-未支付 1-支付成功
     */
    private Integer payStatus;

    /**
     * 支付方式 1-微信 2-支付宝
     */
    private Integer payMethod;

    /**
     * 支付金额
     */
    private BigDecimal payAmount;

    /**
     * 支付时间
     */
    private Date payTime;

    /**
     * 创建时间
     */
    private Date createdAt;

    /**
     * 修改时间
     */
    private Date updatedAt;
}

OrdersMapper： 

package com.example.demo.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import org.springframework.stereotype.Repository;

import com.example.demo.entity.Orders;

import java.util.List;

@Repository
public interface OrdersMapper extends BaseMapper {
	
	Orders getOrderByNo(String orderNo);

	List getOrderList();
}

OrdersMapper.xml： 

	
		order_no, user_id, pay_amount, order_status, pay_status, pay_method,
		pay_time, created_at, updated_at
	


	
		select
		
		from orders where order_no=#{orderNo}
	

	
		select
		
		from orders order by created_at desc limit 10, 10
	

单元测试： 

package com.example.demo;

import com.example.demo.mapper.OrdersMapper;
import com.google.common.hash.BloomFilter;
import com.google.common.hash.Funnels;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

import com.example.demo.entity.Orders;

import java.math.BigDecimal;
import java.util.Date;
import java.util.List;
import java.util.Map;

@RunWith(SpringRunner.class)
@SpringBootTest
public class DemoApplicationTest {

	@Autowired
	private OrdersMapper ordersMapper;

    @Test
	public void saveOrder() {
		Orders orders = new Orders();
		orders.setOrderNo("297454965260130002");
		orders.setUserId(2L);
		orders.setPayAmount(new BigDecimal("32"));
		orders.setOrderStatus(1);
		orders.setPayStatus(1);
		orders.setPayMethod(1);
		orders.setPayTime(new Date());
		orders.setCreatedAt(new Date());
		orders.setUpdatedAt(new Date());
		ordersMapper.insert(orders);
	}

	@Test
	public void contextLoads() {
		Orders order = ordersMapper.getOrderByNo("297454965260130002");
		System.out.println("查询结果：" + order);
	}

	@Test
	public void getOrderList() {
        List orderList = ordersMapper.getOrderList();
        orderList.forEach((e)-> System.out.println("查询结果：" + e));
	}
}

1、插入数据结果，按order_no分片取模，分片数为10，该数据被写入表orders_2：

2、查询数据sql，按order_no分片取模，分片数为10，该数据直接查询表orders_2：

 3、未传分片键，执行ordersMapper.getOrderList(); 查询所有表：

Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@2fcad739] was not registered for synchronization because synchronization is not active
JDBC Connection [org.apache.shardingsphere.driver.jdbc.core.connection.ShardingSphereConnection@4e93d23e] will not be managed by Spring
[INFO ] 2022-12-26 16:38:50,294 --main-- [ShardingSphere-SQL] Logic SQL: select
		 
		order_no, user_id, pay_amount, order_status, pay_status, pay_method,
		pay_time, created_at, updated_at
	 
		from orders order by created_at desc limit 10, 10 
[INFO ] 2022-12-26 16:38:50,294 --main-- [ShardingSphere-SQL] SQLStatement: MySQLSelectStatement(table=Optional.empty, limit=Optional[org.apache.shardingsphere.sql.parser.sql.common.segment.dml.pagination.limit.LimitSegment@6c65c6f0], lock=Optional.empty, window=Optional.empty) 
[INFO ] 2022-12-26 16:38:50,294 --main-- [ShardingSphere-SQL] Actual SQL: db0 ::: select
		 
		order_no, user_id, pay_amount, order_status, pay_status, pay_method,
		pay_time, created_at, updated_at
	 
		from orders_0 order by created_at desc limit 0, 20 
[INFO ] 2022-12-26 16:38:50,294 --main-- [ShardingSphere-SQL] Actual SQL: db0 ::: select
		 
		order_no, user_id, pay_amount, order_status, pay_status, pay_method,
		pay_time, created_at, updated_at
	 
		from orders_1 order by created_at desc limit 0, 20 
[INFO ] 2022-12-26 16:38:50,294 --main-- [ShardingSphere-SQL] Actual SQL: db0 ::: select
		 
		order_no, user_id, pay_amount, order_status, pay_status, pay_method,
		pay_time, created_at, updated_at
	 
		from orders_2 order by created_at desc limit 0, 20 
[INFO ] 2022-12-26 16:38:50,294 --main-- [ShardingSphere-SQL] Actual SQL: db0 ::: select
		 
		order_no, user_id, pay_amount, order_status, pay_status, pay_method,
		pay_time, created_at, updated_at
	 
		from orders_3 order by created_at desc limit 0, 20 
[INFO ] 2022-12-26 16:38:50,294 --main-- [ShardingSphere-SQL] Actual SQL: db0 ::: select
		 
		order_no, user_id, pay_amount, order_status, pay_status, pay_method,
		pay_time, created_at, updated_at
	 
		from orders_4 order by created_at desc limit 0, 20 
[INFO ] 2022-12-26 16:38:50,294 --main-- [ShardingSphere-SQL] Actual SQL: db0 ::: select
		 
		order_no, user_id, pay_amount, order_status, pay_status, pay_method,
		pay_time, created_at, updated_at
	 
		from orders_5 order by created_at desc limit 0, 20 
[INFO ] 2022-12-26 16:38:50,294 --main-- [ShardingSphere-SQL] Actual SQL: db0 ::: select
		 
		order_no, user_id, pay_amount, order_status, pay_status, pay_method,
		pay_time, created_at, updated_at
	 
		from orders_6 order by created_at desc limit 0, 20 
[INFO ] 2022-12-26 16:38:50,294 --main-- [ShardingSphere-SQL] Actual SQL: db0 ::: select
		 
		order_no, user_id, pay_amount, order_status, pay_status, pay_method,
		pay_time, created_at, updated_at
	 
		from orders_7 order by created_at desc limit 0, 20 
[INFO ] 2022-12-26 16:38:50,294 --main-- [ShardingSphere-SQL] Actual SQL: db0 ::: select
		 
		order_no, user_id, pay_amount, order_status, pay_status, pay_method,
		pay_time, created_at, updated_at
	 
		from orders_8 order by created_at desc limit 0, 20 
[INFO ] 2022-12-26 16:38:50,295 --main-- [ShardingSphere-SQL] Actual SQL: db0 ::: select
		 
		order_no, user_id, pay_amount, order_status, pay_status, pay_method,
		pay_time, created_at, updated_at
	 
		from orders_9 order by created_at desc limit 0, 20 
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@2fcad739]

根据以上日志可以看到，逻辑sql为：

select order_no, user_id, pay_amount, order_status, pay_status, pay_method, pay_time, created_at, updated_at  from orders order by created_at desc limit 10, 10;

但实际sql是分别查询orders_0到orders_9，limit 0, 20

这是由于shardingsphere会对逻辑sql进行路由、改写，然后归并结果集。所以在使用中一定要注意，未传分片键查询的话会造成广播路由（用于处理对数据库中与其逻辑表相关的所有真实表的操作，主要包括不带分片键的DQL和DML，以及DDL等)

注：shardingsphere-jdbc在采用主从模型时，为了保证主从库间的事务一致性，避免跨服务的分布式事务，添加@Transactional事务注解开启事务后，事务中的数据读写均用主库。（在JUnit环境下的@Transactional注解，默认情况下会对事务进行回滚）