概述

场景

创建两个数据库

环境搭建

建库、建表

CREATE TABLE `course_1` (
  `cid` bigint(20) NOT NULL,
  `cname` varchar(50) NOT NULL,
  `user_id` bigint(20) NOT NULL,
  `cstatus` varchar(10) NOT NULL,
  PRIMARY KEY (`cid`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

springboot环境搭建

参考ShardingSphere之水平分表实战（三）

配置分片规则

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

# 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}


# 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

编写测试代码

@Test
    void addFk() {
        for (int i = 0; i < 10; i++) {
            Course course = new Course();
            course.setCname("java");
            course.setUserId(101L);
            course.setCstatus("normal");
            courseMapper.insertSelective(course);
        }
    }

    @Test
    public void findCourseDb() {
        Example example = new Example(Course.class);
        Example.Criteria criteria = example.createCriteria();
        criteria.andEqualTo("userId", 100L);
        criteria.andEqualTo("cid", 760185728628948993L);
        Course course = courseMapper.selectOneByExample(example);
        System.out.println(course);

    }