一、 Sharding-jdbc简介
Sharding-jdbc是开源的数据库操作中间件;定位为轻量级Java框架,在Java的JDBC层提供的额外服务。它使用客户端直连数据库,以jar包形式提供服务,无需额外部署和依赖,可理解为增强版的JDBC驱动,完全兼容JDBC和各种ORM框架。
官方文档地址:https://shardingsphere.apache.org/document/current/cn/overview/
本文demo实现了分库分表功能。
二、项目结构
首先创建一个一般的Spring boot项目,项目采用三层架构,结构图如下:项目目录结构图 pom.xml文件如下:
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
4.0.0
org.springframework.boot
spring-boot-starter-parent
2.1.6.RELEASE
com.macky
spring-boot-shardingjdbc
0.0.1-SNAPSHOT
spring-boot-shardingjdbc
Demo project for spring-boot-shardingjdbc
1.8
org.springframework.boot
spring-boot-starter-web
org.springframework.boot
spring-boot-starter-test
test
mysql
mysql-connector-java
runtime
com.baomidou
mybatis-plus-boot-starter
3.1.1
io.shardingsphere
sharding-jdbc-spring-boot-starter
3.1.0
io.shardingsphere
sharding-jdbc-spring-namespace
3.1.0
org.projectlombok
lombok
org.springframework.boot
spring-boot-maven-plugin
实体类以书本为例:
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: 书籍是实体类
* @date 2019/7/13 15:23
*/
@Data
@EqualsAndHashCode(callSuper = true)
@Accessors(chain = true)
@TableName("book")
public class Book extends Model
{ private int id;
private String name;
private int count;
}
开放保存和查询两个接口,代码如下:
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
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
{ }
创建数据库表,DDL语句如下:
#创建数据库表数据
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;
配置分库分表策略application.properties:
# 数据源 db0,db1,db2
sharding.jdbc.datasource.names=db0,db1,db2
# 第一个数据库
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
# 第二个数据库
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
# 第三个数据库
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
# 水平拆分的数据库(表) 配置分库 + 分表策略 行表达式分片策略
# 分库策略
sharding.jdbc.config.sharding.default-database-strategy.inline.sharding-column=id
sharding.jdbc.config.sharding.default-database-strategy.inline.algorithm-expression=db$->{id % 3}
# 分表策略 其中book为逻辑表 分表主要取决于id行
sharding.jdbc.config.sharding.tables.book.actual-data-nodes=db$->{0..2}.book_$->{0..2}
sharding.jdbc.config.sharding.tables.book.table-strategy.inline.sharding-column=count
# 分片算法表达式
sharding.jdbc.config.sharding.tables.book.table-strategy.inline.algorithm-expression=book_$->{count % 3}
# 主键 UUID 18位数 如果是分布式还要进行一个设置 防止主键重复
#sharding.jdbc.config.sharding.tables.user.key-generator-column-name=id
# 打印执行的数据库以及语句
sharding.jdbc.config.props..sql.show=true
spring.main.allow-bean-definition-overriding=true
#读写分离
sharding.jdbc.datasource.dsmaster =
接口测试使用postman
示例:GET请求------>http://localhost:8080/book POST请求:------->http://localhost:8080/book?id=1&name=java编程思想&count=8
demo的github地址:https://github.com/Macky-He/spring-boot--shardingsphere-examples
三、总结
分库分表实现按照官方文档做一个demo是第一步,如需深入还需要研究源码,研究架构,研究思想;此文仅作为入门demo搭建指南,如需深入理解,还请移步至官方文档,
官方文档:https://shardingsphere.apache.org/document/current/cn/manual/sharding-jdbc/usage/sharding/