一、Sharding-JDBC简介：
Sharding-JDBC又称ShardingSphere，一个开放源代码生态系统，由一组分布式数据库中间件解决方案组成，其中又包括JDBC，代理和Sidecar（计划）。它们都提供数据分片，分布式事务和数据库编排功能，适用于Java同构，异构语言和云原生等各种情况。
二、创建项目如下：
使用STS创建Spring Boot项目，使用MVC三层结构开发代码：
1）配置POM添加以下依赖
<!--mysql-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<!--Mybatis-Plus-->
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>3.1.1</version>
</dependency>
<!--shardingsphere start-->
<!-- for spring boot -->
<dependency>
<groupId>io.shardingsphere</groupId>
<artifactId>sharding-jdbc-spring-boot-starter</artifactId>
<version>3.1.0</version>
</dependency>
<!-- for spring namespace -->
<dependency>
<groupId>io.shardingsphere</groupId>
<artifactId>sharding-jdbc-spring-namespace</artifactId>
<version>3.1.0</version>
</dependency>
<!--shardingsphere end-->
<!--lombok-->
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</dependency>
2）创建实体类
@Data
@EqualsAndHashCode(callSuper = true)
@Accessors(chain = true)
@TableName("book")
public class Book extends Model<Book> {
private int id;
private String name;
private int count;
}
3）创建service
public interface BookService {
List<Book> getBookList();
boolean save(Book book);
}
4）创建serviceImpl
@Service
public class BookServiceImpl extends ServiceImpl<BookMapper, Book>implements BookService{
@Override
public List<Book> getBookList() {
return baseMapper.selectList(Wrappers.<Book>lambdaQuery());
}
@Override
public boolean save(Book book) {
return super.save(book);
}
}
5)创建controller，并实现以下两个方法
@RestController
public class BookController {
@Autowired
BookService bookService;
@RequestMapping(value = "/book", method = RequestMethod.GET)
public List<Book> getItems(){
return bookService.getBookList();
}
@RequestMapping(value = "/book",method = RequestMethod.POST)
public Boolean saveItem(Book book){
return bookService.save(book);
}
}
6）application.properties配置如下
# 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=root
# 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=root
# 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=root
# 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_$->{0..1}
sharding.jdbc.config.sharding.tables.book.table-strategy.inline.sharding-column=count
# 分片算法表达式
sharding.jdbc.config.sharding.tables.book.table-strategy.inline.algorithm-expression=book_$->{count % 2}
# 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=
7)sql建表语句如下
#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;
三、启动项目用postman访问如下地址：
