概述

场景

在实际工作中，有些表需要参与分片操作，有些表则无需分片，那么这种场景下，sharding-jdbc该如何配置呢？

SpringBoot环境搭建

application.properties配置

涉及未分配表的配置如下，只需要指定default-data-source-name即可。

# 默认数据库,不分片的表都在这里
spring.shardingsphere.datasource.mx.type=com.alibaba.druid.pool.DruidDataSource
spring.shardingsphere.datasource.mx.driver-class-name=com.mysql.cj.jdbc.Driver
# course_db数据库无需单独建立，也可以是和其他的分片数据库相同，比如可以是edu_db_1
spring.shardingsphere.datasource.mx.url=jdbc:mysql://localhost:3306/course_db?serverTimezone=GMT%2B8
spring.shardingsphere.datasource.mx.username=root
spring.shardingsphere.datasource.mx.password=123456

# 默认数据源，未分片的表默认执行库
spring.shardingsphere.sharding.default-data-source-name=mx

全量配置如下

# 配置分片策略
# 配置数据源
spring.shardingsphere.datasource.names=m0,m1,m2,mx

# 默认数据库,不分片的表都在这里
spring.shardingsphere.datasource.mx.type=com.alibaba.druid.pool.DruidDataSource
spring.shardingsphere.datasource.mx.driver-class-name=com.mysql.cj.jdbc.Driver
spring.shardingsphere.datasource.mx.url=jdbc:mysql://localhost:3306/course_db?serverTimezone=GMT%2B8
spring.shardingsphere.datasource.mx.username=root
spring.shardingsphere.datasource.mx.password=123456

spring.shardingsphere.datasource.m1.type=com.alibaba.druid.pool.DruidDataSource
spring.shardingsphere.datasource.m1.driver-class-name=com.mysql.cj.jdbc.Driver
spring.shardingsphere.datasource.m1.url=jdbc:mysql://localhost:3306/edu_db_1?serverTimezone=GMT%2B8
spring.shardingsphere.datasource.m1.username=root
spring.shardingsphere.datasource.m1.password=123456

spring.shardingsphere.datasource.m2.type=com.alibaba.druid.pool.DruidDataSource
spring.shardingsphere.datasource.m2.driver-class-name=com.mysql.cj.jdbc.Driver
spring.shardingsphere.datasource.m2.url=jdbc:mysql://localhost:3306/edu_db_2?serverTimezone=GMT%2B8
spring.shardingsphere.datasource.m2.username=root
spring.shardingsphere.datasource.m2.password=123456

spring.shardingsphere.datasource.m0.type=com.alibaba.druid.pool.DruidDataSource
spring.shardingsphere.datasource.m0.driver-class-name=com.mysql.cj.jdbc.Driver
spring.shardingsphere.datasource.m0.url=jdbc:mysql://localhost:3306/user_db?serverTimezone=GMT%2B8
spring.shardingsphere.datasource.m0.username=root
spring.shardingsphere.datasource.m0.password=123456

# 默认数据源，未分片的表默认执行库
spring.shardingsphere.sharding.default-data-source-name=mx


# 指定course表分布情况,配置表在哪个数据库中,表名称都是什么
spring.shardingsphere.sharding.tables.course.actual-data-nodes=m$->{1..2}.course_$->{1..2}
# 指定course主键cid生成策略SNOWFLAKE
spring.shardingsphere.sharding.tables.course.key-generator.column=cid
spring.shardingsphere.sharding.tables.course.key-generator.type=SNOWFLAKE
# 指定表分片策略, cid是偶数添加到course_1表中,cid是奇数添加到course_2
spring.shardingsphere.sharding.tables.course.table-strategy.inline.sharding-column=cid
spring.shardingsphere.sharding.tables.course.table-strategy.inline.algorithm-expression=course_$->{cid % 2 + 1}

# 指定库的中course表的分片策略
spring.shardingsphere.sharding.tables.course.database-strategy.inline.sharding-column=user_id
spring.shardingsphere.sharding.tables.course.database-strategy.inline.algorithm-expression=m$->{user_id % 2 + 1}

# 指定t_user表分布情况,配置表在哪个数据库中,表名称都是什么
spring.shardingsphere.sharding.tables.t_user.actual-data-nodes=m0.t_user
# 指定t_user主键user_id生成策略SNOWFLAKE
spring.shardingsphere.sharding.tables.t_user.key-generator.column=user_id
spring.shardingsphere.sharding.tables.t_user.key-generator.type=SNOWFLAKE

# 指定表分片策略
spring.shardingsphere.sharding.tables.t_user.table-strategy.inline.sharding-column=user_id
spring.shardingsphere.sharding.tables.t_user.table-strategy.inline.algorithm-expression=t_user

# 打开sql输出日志
spring.shardingsphere.props.sql.show=true
# 解决一个Course实体类不能对应两张表的问题
spring.main.allow-bean-definition-overriding=true

表结构

CREATE TABLE `t_study` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) DEFAULT NULL,
  `course_name` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

测试代码

package com.study.shardingjdbcdemo.entity;

import lombok.Data;

import javax.persistence.Id;
import javax.persistence.Table;

@Data
@Table(name = "t_study")
public class Study {
    @Id
    private Long id;

    private String name;

    private String courseName;
}

package com.study.shardingjdbcdemo.mapper;

import com.study.shardingjdbcdemo.entity.Study;
import org.springframework.stereotype.Repository;
import tk.mybatis.mapper.common.Mapper;

@Repository
public interface StudyMapper extends Mapper<Study> {
}

@Test
    public void defaultDb() {
        Study study = new Study();
        study.setName("xm");
        study.setCourseName("mysql");
        studyMapper.insert(study);
    }