前言
随着业务规模的增长,单一数据库往往无法满足高性能、高并发的需求。shardingsphere 作为 apache 基金会顶级项目,提供了完整的分布式数据库解决方案,其中分库分表功能是最核心的能力之一。本文将深入探讨 shardingsphere 的分库分表原理,并提供 spring boot 集成实践方案。

理论基础
1. 分库分表概念
垂直分库:按照业务模块将数据分散到不同的数据库实例
水平分表:将单表数据按照某种规则分散到多个物理表中
2. shardingsphere 架构组成
- sharding-jdbc:轻量级 java 框架,以 jar 包形式提供服务
- sharding-proxy:数据库代理,提供透明化的数据库访问
- sharding-sidecar:云原生数据库代理(开发中)
3. 核心组件
// 数据源配置 datasource datasource = new shardingspheredatasource(); // 分片规则配置 shardingruleconfiguration shardingruleconfig = new shardingruleconfiguration(); // 分片策略 standardshardingstrategyconfiguration strategyconfig = new standardshardingstrategyconfiguration();
4. 原理分析
- sql 解析
sharding-jdbc 会对传入的 sql 语句进行解析,识别出其中的分片键(sharding key)以及相关的表名、字段等信息。这是实现分片路由的基础。
public sqlstatement parse(string sql, boolean usecache);
- 分片路由
根据解析出的分片键和配置的分片规则,sharding-jdbc 会计算出 sql 应该路由到哪些实际的数据源和表。这个过程涉及到分片算法的应用,比如取模、范围分片等。
public routecontext route(sqlstatement sqlstatement, shardingrule shardingrule);
- sql 改写
在确定了目标数据源和表之后,sharding-jdbc 会将原始 sql 改写为目标数据库可以执行的 sql。例如,将逻辑表名替换为实际的物理表名。
public sqlrewriteresult rewrite(routecontext routecontext);
- 结果归并
当查询涉及多个数据源或表时,sharding-jdbc 会将各个数据源返回的结果进行归并,最终返回给应用层一个统一的结果集。
public mergedresult merge(list<queryresult> queryresults, sqlstatement sqlstatement);
- 事务管理
sharding-jdbc 还支持分布式事务管理,确保在多个数据源之间的操作具有一致性。
public void begin(); public void commit(); public void rollback();
spring boot 集成方案
1. maven 依赖配置
<dependency>
<groupid>org.apache.shardingsphere</groupid>
<artifactid>shardingsphere-jdbc-core-spring-boot-starter</artifactid>
<version>5.2.1</version>
<exclusions>
<exclusion>
<groupid>org.yaml</groupid>
<artifactid>snakeyaml</artifactid>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupid>org.yaml</groupid>
<artifactid>snakeyaml</artifactid>
<!-- springboot 2.x 使用 shardingsphere 推荐的版本 -->
<version>1.33</version>
</dependency>2. 配置文件设置
spring:
shardingsphere:
datasource:
names: ds0,ds1
ds0:
driver-class-name: com.mysql.cj.jdbc.driver
url: jdbc:mysql://localhost:3306/cce-demo
username: root
password: 12345678
type: com.zaxxer.hikari.hikaridatasource
ds1:
driver-class-name: com.mysql.cj.jdbc.driver
url: jdbc:mysql://localhost:3306/cce-demo-temp
username: root
password: 12345678
type: com.zaxxer.hikari.hikaridatasource
rules:
sharding:
tables:
mp_user:
actual-data-nodes: ds${0..1}.mp_user_${0..3}
table-strategy:
standard:
sharding-column: user_id
sharding-algorithm-name: mp-user-inline
database-strategy:
standard:
sharding-column: user_id
sharding-algorithm-name: database-inline
sharding-algorithms:
mp-user-inline:
type: inline
props:
algorithm-expression: mp_user_${user_id % 4}
database-inline:
type: inline
props:
algorithm-expression: ds${user_id % 2}3. 测试用例
/**
* mpusertest
* 所有操作都必须包含分表键,不然无法路由
* @author senfel
* @version 1.0
* @date 2026/1/30 11:42
*/
@springboottest
@testmethodorder(methodorderer.orderannotation.class)
public class mpusertest {
@resource
private mpusermapper mpusermapper;
private static final string testopenid = "test_openid_" + system.currenttimemillis();
private static final long testuseridnumber = generatenumericuserid();
/**
* 生成数字格式的用户id
* @author senfel
* @date 2026/1/30 16:59
* @return java.lang.long
*/
private static long generatenumericuserid() {
// 使用时间戳和随机数生成数字id
long timestamp = system.currenttimemillis();
long random = (long) (math.random() * 1000000l);
return timestamp + random;
}
/**
* test
* @author senfel
* @date 2026/1/30 16:59
* @return void
*/
@test
@order(1)
public void test() {
//插入
mpuser user = mpuser.builder()
.openid(testopenid)
.deleted(false)
.userid(testuseridnumber)
.build();
int result = mpusermapper.insert(user);
system.err.println("userid: " + user.getuserid());
asserttrue(result > 0, "插入用户应该成功");
//查询
lambdaquerywrapper<mpuser> querywrapper = new lambdaquerywrapper<>();
querywrapper.eq(mpuser::getuserid, user.getuserid());
list<mpuser> userlist = mpusermapper.selectlist(querywrapper);
assertnotnull(userlist, "根据userid查询结果不应该为null");
//修改
lambdaupdatewrapper<mpuser> updatewrapper = new lambdaupdatewrapper<>();
updatewrapper.eq(mpuser::getuserid, user.getuserid())
.set(mpuser::getuserid, testuseridnumber);
result = mpusermapper.update(null, updatewrapper);
asserttrue(result > 0, "根据userid更新用户应该成功");
//删除
result = mpusermapper.delete(updatewrapper);
asserttrue(result > 0, "根据userid删除用户应该成功");
}
}4. 测试效果
userid: 1769764291467 creating a new sqlsession sqlsession [org.apache.ibatis.session.defaults.defaultsqlsession@2d91f007] was not registered for synchronization because synchronization is not active jdbc connection [org.apache.shardingsphere.driver.jdbc.core.connection.shardingsphereconnection@3dd09249] will not be managed by spring ==> preparing: select id,openid,deleted,user_id from mp_user where (user_id = ?) ==> parameters: 1769764291467(long) <== columns: id, openid, deleted, user_id <== row: 8388609, test_openid_1769763436874, 0, 1769764291467 <== total: 1 closing non transactional sqlsession [org.apache.ibatis.session.defaults.defaultsqlsession@2d91f007] creating a new sqlsession sqlsession [org.apache.ibatis.session.defaults.defaultsqlsession@12888eb5] was not registered for synchronization because synchronization is not active jdbc connection [org.apache.shardingsphere.driver.jdbc.core.connection.shardingsphereconnection@205339e0] will not be managed by spring ==> preparing: update mp_user set user_id=? where (user_id = ?) ==> parameters: 1769764291467(long), 1769764291467(long) <== updates: 1 closing non transactional sqlsession [org.apache.ibatis.session.defaults.defaultsqlsession@12888eb5] creating a new sqlsession sqlsession [org.apache.ibatis.session.defaults.defaultsqlsession@76f3f810] was not registered for synchronization because synchronization is not active jdbc connection [org.apache.shardingsphere.driver.jdbc.core.connection.shardingsphereconnection@7d7efdf5] will not be managed by spring ==> preparing: delete from mp_user where (user_id = ?) ==> parameters: 1769764291467(long) <== updates: 1 closing non transactional sqlsession [org.apache.ibatis.session.defaults.defaultsqlsession@76f3f810]
实际应用场景
1. 电商订单系统
@entity
@table(name = "order")
public class order {
@id
private long orderid;
private long userid;
private bigdecimal amount;
private localdatetime createtime;
// getter/setter...
}
// 查询示例
@repository
public interface orderrepository extends jparepository<order, long> {
list<order> findbyuserid(long userid);
@query("select o from order o where o.userid = :userid and o.createtime between :starttime and :endtime")
list<order> findordersbyuseridandtimerange(@param("userid") long userid,
@param("starttime") localdatetime starttime,
@param("endtime") localdatetime endtime);
}2. 日志分表策略
# 按月份分表配置
spring:
shardingsphere:
rules:
sharding:
tables:
system_log:
actual-data-nodes: ds0.system_log_${202301..202312}
table-strategy:
standard:
sharding-column: create_time
sharding-algorithm-name: log-month-sharding性能优化建议
1. 连接池配置
spring:
shardingsphere:
props:
sql-show: true
max-connections-size-per-query: 10
acceptor-size: 162. 查询优化
- 合理设计分片键,避免跨分片查询
- 使用绑定表减少笛卡尔积
- 合理设置分片数量,避免过多分片影响性能
总结
shardingsphere 提供了完善的分库分表解决方案,通过合理的配置和使用,可以有效解决单体数据库的性能瓶颈问题。在实际应用中需要注意:
1.分片键选择:选择合适的分片键是成功的关键
2.数据迁移:制定完善的数据迁移方案
3.监控告警:建立完善的监控体系
4.版本升级:关注新版本特性,及时升级
通过本文的介绍和实践方案,我们可以快速掌握 shardingsphere 的核心功能,并在 spring boot 项目中成功集成分库分表能力。
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