一、 Sharding-jdbc簡介

“
Sharding-jdbc是開源的數據庫操作中間件；定位為輕量級Java框架，在Java的JDBC層提供的額外服務。它使用客戶端直連數據庫，以jar包形式提供服務，無需額外部署和依賴，可理解為增強版的JDBC驅動，完全兼容JDBC和各種ORM框架。

官方文檔地址：https://shardingsphere.apache.org/document/current/cn/overview/

本文demo實現了分庫分表功能。如有錯誤，歡迎各位在評論中指出。不勝感激！

二、項目結構

首先創(chuàng)建一個一般的Spring boot項目，項目采用三層架構，結構圖如下：

POM.xml文件如下：


<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?http://maven.apache.org/xsd/maven-4.0.0.xsd">
????<modelVersion>4.0.0modelVersion>
????<parent>
????????<groupId>org.springframework.bootgroupId>
????????<artifactId>spring-boot-starter-parentartifactId>
????????<version>2.1.6.RELEASEversion>
????????<relativePath/>?
????parent>
????<groupId>com.mackygroupId>
????<artifactId>spring-boot-shardingjdbcartifactId>
????<version>0.0.1-SNAPSHOTversion>
????<name>spring-boot-shardingjdbcname>
????<description>Demo?project?for?spring-boot-shardingjdbcdescription>

????<properties>
????????<java.version>1.8java.version>
????properties>

????<dependencies>
????????<dependency>
????????????<groupId>org.springframework.bootgroupId>
????????????<artifactId>spring-boot-starter-webartifactId>
????????dependency>

????????<dependency>
????????????<groupId>org.springframework.bootgroupId>
????????????<artifactId>spring-boot-starter-testartifactId>
????????????<scope>testscope>
????????dependency>
????????
????????<dependency>
????????????<groupId>mysqlgroupId>
????????????<artifactId>mysql-connector-javaartifactId>
????????????<scope>runtimescope>
????????dependency>
????????
????????<dependency>
????????????<groupId>com.baomidougroupId>
????????????<artifactId>mybatis-plus-boot-starterartifactId>
????????????<version>3.1.1version>
????????dependency>
????????
????????
????????<dependency>
????????????<groupId>io.shardingspheregroupId>
????????????<artifactId>sharding-jdbc-spring-boot-starterartifactId>
????????????<version>3.1.0version>
????????dependency>
????????
????????<dependency>
????????????<groupId>io.shardingspheregroupId>
????????????<artifactId>sharding-jdbc-spring-namespaceartifactId>
????????????<version>3.1.0version>
????????dependency>
????????
????????
????????<dependency>
????????????<groupId>org.projectlombokgroupId>
????????????<artifactId>lombokartifactId>
????????dependency>
????dependencies>

????<build>
????????<plugins>
????????????<plugin>
????????????????<groupId>org.springframework.bootgroupId>
????????????????<artifactId>spring-boot-maven-pluginartifactId>
????????????plugin>
????????plugins>
????build>

project>

實體類以書本為例

package?com.macky.springbootshardingjdbc.entity;

import?com.baomidou.mybatisplus.annotation.TableName;
import?com.baomidou.mybatisplus.extension.activerecord.Model;
import?groovy.transform.EqualsAndHashCode;
import?lombok.Data;
import?lombok.experimental.Accessors;

/**
?*?@author?Macky
?*?@Title?class?Book
?*?@Description:?書籍是實體類
?*?@date?2019/7/13?15:23
?*/
@Data
@EqualsAndHashCode(callSuper?=?true)
@Accessors(chain?=?true)
@TableName("book")
public?class?Book?extends?Model<Book>?{
????private?int?id;
????private?String?name;
????private?int?count;
}

開放保存和查詢兩個接口，代碼如下：

package?com.macky.springbootshardingjdbc.controller;

import?com.macky.springbootshardingjdbc.entity.Book;
import?com.macky.springbootshardingjdbc.service.BookService;
import?org.springframework.beans.factory.annotation.Autowired;
import?org.springframework.web.bind.annotation.*;

import?java.util.List;

/**
?*?@author?Macky
?*?@Title?class?BookController
?*?@Description:?TODO
?*?@date?2019/7/12?20:53
?*/
@RestController
public?class?BookController?{

????@Autowired
????BookService?bookService;

????@RequestMapping(value?=?"/book",?method?=?RequestMethod.GET)
????public?List?getItems(){
????????return?bookService.getBookList();
????}

????@RequestMapping(value?=?"/book",method?=?RequestMethod.POST)
????public?Boolean?saveItem(Book?book){
????????return?bookService.save(book);
????}
}

BookServiceImpl.java

package?com.macky.springbootshardingjdbc.service.impl;

import?com.baomidou.mybatisplus.core.toolkit.Wrappers;
import?com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import?com.macky.springbootshardingjdbc.entity.Book;
import?com.macky.springbootshardingjdbc.mapper.BookMapper;
import?com.macky.springbootshardingjdbc.service.BookService;
import?org.springframework.stereotype.Service;

import?java.util.List;

/**
?*?@author?Macky
?*?@Title?class?BookServiceImpl
?*?@Description:?TODO
?*?@date?2019/7/12?20:47
?*/
@Service
public?class?BookServiceImpl?extends?ServiceImpl<BookMapper,?Book>?implements?BookService?{

????@Override
????public?List?getBookList()?{
????????return?baseMapper.selectList(Wrappers.lambdaQuery());
????}

????@Override
????public?boolean?save(Book?book)?{
????????return?super.save(book);
????}
}

BookMapper.java

package?com.macky.springbootshardingjdbc.mapper;

import?com.baomidou.mybatisplus.core.mapper.BaseMapper;
import?com.macky.springbootshardingjdbc.entity.Book;

/**
?*?@author?Macky
?*?@Title?class?BookMapper
?*?@Description:?TODO
?*?@date?2019/7/12?20:46
?*/
public?interface?BookMapper?extends?BaseMapper<Book>?{
}

創(chuàng)建數據庫表，DDL語句如下

創(chuàng)建數據庫表數據
CREATE?DATABASE?IF?NOT?EXISTS?`db0`;
USE?`db0`;
DROP?TABLE?IF?EXISTS?`book_0`;
CREATE?TABLE?`book_0`?(
?`id`?INT?(?11?)?NOT?NULL,
?`name`?VARCHAR?(?255?)?DEFAULT?NULL,
?`count`?INT?(?11?)?DEFAULT?NULL,
?PRIMARY?KEY?(?`id`?)
)?ENGINE?=?INNODB?DEFAULT?CHARSET?=?utf8mb4;
DROP?TABLE?IF?EXISTS?`book_1`;
CREATE?TABLE?`book_1`?(
?`id`?INT?(?11?)?NOT?NULL,
?`name`?VARCHAR?(?255?)?DEFAULT?NULL,
?`count`?INT?(?11?)?DEFAULT?NULL,
?PRIMARY?KEY?(?`id`?)
)?ENGINE?=?INNODB?DEFAULT?CHARSET?=?utf8mb4;

CREATE?DATABASE?IF?NOT?EXISTS?`db1`;
USE?`db1`;
DROP?TABLE?IF?EXISTS?`book_0`;
CREATE?TABLE?`book_0`?(
?`id`?INT?(?11?)?NOT?NULL,
?`name`?VARCHAR?(?255?)?DEFAULT?NULL,
?`count`?INT?(?11?)?DEFAULT?NULL,
?PRIMARY?KEY?(?`id`?)
)?ENGINE?=?INNODB?DEFAULT?CHARSET?=?utf8mb4;
DROP?TABLE?IF?EXISTS?`book_1`;
CREATE?TABLE?`book_1`?(
?`id`?INT?(?11?)?NOT?NULL,
?`name`?VARCHAR?(?255?)?DEFAULT?NULL,
?`count`?INT?(?11?)?DEFAULT?NULL,
?PRIMARY?KEY?(?`id`?)
)?ENGINE?=?INNODB?DEFAULT?CHARSET?=?utf8mb4;

CREATE?DATABASE?IF?NOT?EXISTS?`db2`;
USE?`db2`;
DROP?TABLE?IF?EXISTS?`book_0`;
CREATE?TABLE?`book_0`?(
?`id`?INT?(?11?)?NOT?NULL,
?`name`?VARCHAR?(?255?)?DEFAULT?NULL,
?`count`?INT?(?11?)?DEFAULT?NULL,
?PRIMARY?KEY?(?`id`?)
)?ENGINE?=?INNODB?DEFAULT?CHARSET?=?utf8mb4;
DROP?TABLE?IF?EXISTS?`book_1`;
CREATE?TABLE?`book_1`?(
?`id`?INT?(?11?)?NOT?NULL,
?`name`?VARCHAR?(?255?)?DEFAULT?NULL,
?`count`?INT?(?11?)?DEFAULT?NULL,
?PRIMARY?KEY?(?`id`?)
)?ENGINE?=?INNODB?DEFAULT?CHARSET?=?utf8mb4;

配置分庫分表策略application.properties：

> 推薦一個艿艿寫的 3000+ Star 的 SpringCloud Alibaba 電商開源項目的倉庫：

# 數據源 db0,db1,db2
sharding.jdbc.datasource.names=db0,db1,db2
# 第一個數據庫
sharding.jdbc.datasource.db0.type=com.zaxxer.hikari.HikariDataSource
sharding.jdbc.datasource.db0.driver-class-name=com.mysql.cj.jdbc.Driver
sharding.jdbc.datasource.db0.jdbc-url=jdbc:mysql://localhost:3306/db0?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC
sharding.jdbc.datasource.db0.username=root
sharding.jdbc.datasource.db0.password=Aa123456

# 第二個數據庫
sharding.jdbc.datasource.db1.type=com.zaxxer.hikari.HikariDataSource
sharding.jdbc.datasource.db1.driver-class-name=com.mysql.cj.jdbc.Driver
sharding.jdbc.datasource.db1.jdbc-url=jdbc:mysql://localhost:3306/db1?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC
sharding.jdbc.datasource.db1.username=root
sharding.jdbc.datasource.db1.password=Aa123456

# 第三個數據庫
sharding.jdbc.datasource.db2.type=com.zaxxer.hikari.HikariDataSource
sharding.jdbc.datasource.db2.driver-class-name=com.mysql.cj.jdbc.Driver
sharding.jdbc.datasource.db2.jdbc-url=jdbc:mysql://localhost:3306/db2?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC
sharding.jdbc.datasource.db2.username=root
sharding.jdbc.datasource.db2.password=Aa123456

# 水平拆分的數據庫（表） 配置分庫 + 分表策略 行表達式分片策略
# 分庫策略
sharding.jdbc.config.sharding.default-database-strategy.inline.sharding-column=id
sharding.jdbc.config.sharding.default-database-strategy.inline.algorithm-expression=db$->{id % 3}

# 分表策略 其中book為邏輯表 分表主要取決于id行
sharding.jdbc.config.sharding.tables.book.actual-data-nodes=db$->{0..2}.book_$->{0..2}
sharding.jdbc.config.sharding.tables.book.table-strategy.inline.sharding-column=count
# 分片算法表達式
sharding.jdbc.config.sharding.tables.book.table-strategy.inline.algorithm-expression=book_$->{count % 3}

# 主鍵 UUID 18位數 如果是分布式還要進行一個設置 防止主鍵重復
#sharding.jdbc.config.sharding.tables.user.key-generator-column-name=id

# 打印執(zhí)行的數據庫以及語句
sharding.jdbc.config.props..sql.show=true
spring.main.allow-bean-definition-overriding=true

#讀寫分離
sharding.jdbc.datasource.dsmaster =

接口測試使用postman

示例：

GET請求------>http://localhost:8080/book
POST請求：------->http://localhost:8080/book?id=1&name=java編程思想&count=8

demo的github地址：

https://github.com/Macky-He/spring-boot--shardingsphere-examples 如各位覺得有幫助的話，還請給個star鼓勵鼓勵博主，謝謝！

三、總結

分庫分表實現按照官方文檔做一個demo是第一步，如需深入還需要研究源碼，研究架構，研究思想；此文僅作為入門demo搭建指南，如需深入理解，還請移步至官方文檔。

參考資料

官方文檔：https://shardingsphere.apache.org/document/current/cn/manual/sharding-jdbc/usage/sharding/

來源：blog.csdn.net/Macky_He/article/details/95754402



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Spring Boot 集成 Sharding-JDBC + Mybatis-Plus 實現分庫分表

一、 Sharding-jdbc簡介

二、項目結構

接口測試使用postman

三、總結

參考資料

二、項目結構

三、總結