这是一个shardingsphere-jdbc + mybatis plus + flyway + springboot +mysql +分布式主键ID + Nacos案例
- pom.xml中加入sharding-jdbc-spring-boot-starter
<?xml version="1.0" encoding="UTF-8"?>
<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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.2.4.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.watermelon.sharding_jdbc_sample</groupId>
<artifactId>sharding_jdbc_sample</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>sharding_jdbc_sample</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>3.4.1</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
<dependency>
<groupId>org.flywaydb</groupId>
<artifactId>flyway-core</artifactId>
<version>5.2.3</version>
</dependency>
<dependency>
<groupId>org.apache.shardingsphere</groupId>
<artifactId>sharding-jdbc-spring-boot-starter</artifactId>
<version>4.1.1</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<configuration>
<excludes>
<exclude>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</exclude>
</excludes>
</configuration>
</plugin>
</plugins>
</build>
</project>
- application.yml配置如下
server:
port: 8082
spring:
shardingsphere:
datasource:
names: ds0
ds0:
type: com.zaxxer.hikari.HikariDataSource #必填
jdbc-url: jdbc:mysql://localhost:3306/sharding_jdbc_sample?useSSL=false&&characterEncoding=UTF-8 #必填
username: root #必填
password: root #必填
sharding:
tables:
commodity:
actual-data-nodes: ds0.commodity_$->{0..3} # sql查询时，会使用commodity_{0..3}的格式去查实际表
table-strategy:
inline:
sharding-column: commodityId # 分片ID
algorithm-expression: commodity_$->{(commodityId.hashCode() & Integer.MAX_VALUE) % 4} # 通过此表达式来计算具体的commodity表
props:
sql:
show: false #可打印实际sql，分表后的实际表名
mybatis-plus:
configuration:
map-underscore-to-camel-case: false
# log-impl: org.apache.ibatis.logging.stdout.StdOutImpl #sql日志，会把查询结果也打印出来
logging:
level:
com:
watermelon:
sharding_jdbc_sample:
dao: debug
- mybatis plus使用分布式主键(sharding jdbc内置的雪花算法实现)
package com.watermelon.sharding_jdbc_sample.config;
import com.baomidou.mybatisplus.core.incrementer.IdentifierGenerator;
import org.apache.shardingsphere.core.strategy.keygen.SnowflakeShardingKeyGenerator;
import org.springframework.stereotype.Component;
import java.util.Properties;
/**
*
* @author watermelon
*/
@Component
public class CustomIdGenerator implements IdentifierGenerator {
@Override
public Number nextId(Object entity) {
SnowflakeShardingKeyGenerator snowflakeShardingKeyGenerator=new SnowflakeShardingKeyGenerator();
/**
* 分布式系统中，每个服务的worker.id都需要改成不一样的值,worker.id的范围是从0到1024
*/
Properties properties=new Properties();
properties.setProperty("worker.id","1000");
snowflakeShardingKeyGenerator.setProperties(properties);
return (Number) snowflakeShardingKeyGenerator.generateKey();
}
}
- entity中使用配置的雪花算法生成ID
package com.watermelon.sharding_jdbc_sample.entity;
import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.Data;
import lombok.experimental.Accessors;
/**
* @author watermelon
*/
@TableName("commodity")
@Data
@Accessors(chain = true)
public class Commodity {
/**
* 一定要用ASSIGN_ID,这样使用的就是配置的雪花算法了
*/
@TableId(type = IdType.ASSIGN_ID)
private Long id;
private String commodityId;
private String nonce;
}
- 增加对flyway的支持
因为数据源配置在sharding jdbc的属性里了，所以我们这里要编程式的配置flyway
package com.watermelon.sharding_jdbc_sample.config;
import lombok.extern.slf4j.Slf4j;
import org.apache.shardingsphere.shardingjdbc.jdbc.core.datasource.ShardingDataSource;
import org.flywaydb.core.Flyway;
import org.flywaydb.core.api.configuration.ClassicConfiguration;
import org.springframework.context.annotation.Bean;
import org.springframework.stereotype.Component;
import javax.annotation.Resource;
import javax.sql.DataSource;
import java.util.Map;
/**
* @author watermelon
*/
@Component
@Slf4j
public class FlywayInit {
@Resource
private ShardingDataSource shardingDataSource;
@Bean
public void flyway2(){
Map<String, DataSource> dataSourceMap = shardingDataSource.getDataSourceMap();
for (Map.Entry<String, DataSource> entry : dataSourceMap.entrySet()) {
ClassicConfiguration configuration = new ClassicConfiguration();
configuration.setDataSource(entry.getValue());
Flyway flyway = new Flyway(configuration);
flyway.migrate();
}
}
}