Sharding realizes the separation of database read and write
In order to reduce a large number of concurrent read operations and fewer write operations at the same time, the database can be split into a main library and a slave library. The main library is mainly used for data write and delete operations, and the slave library is used for data read operations. , Usually a one-master, multiple-slave configuration
Sharding provides a data mechanism with one master and multiple slaves. Write and delete data are automatically mapped to the master database, and read query operations are automatically mapped to the slave database, but it does not support the data synchronization operation of the master-slave database. The data synchronization is automatically supported by mysql. of
For mysql data synchronization settings, please refer to:
mySQL master-slave database synchronization settings
Data table structure:
studnet1
student2
1.pom dependency
<!--web启动器-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!--mysql驱动-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
<version>5.1.47</version>
</dependency>
<!--mybatis启动器-->
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>2.0.0</version>
</dependency>
<!--druid连接池-->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid-spring-boot-starter</artifactId>
<version>1.1.16</version>
</dependency>
<!--sharding启动器-->
<dependency>
<groupId>org.apache.shardingsphere</groupId>
<artifactId>sharding-jdbc-spring-boot-starter</artifactId>
<version>4.0.0-RC1</version>
</dependency>
<!--测试依赖-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<scope>annotationProcessor</scope>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<scope>test</scope>
</dependency>
2.application configuration
server.port=8080
spring.application.name=sharding
mybatis.configuration.map-underscore-to-camel-case=true
# 配置多数据源
spring.shardingsphere.datasource.names=m1,s0
# 主数据源
spring.shardingsphere.datasource.m1.type=com.alibaba.druid.pool.DruidDataSource
spring.shardingsphere.datasource.m1.driver-class-name=com.mysql.jdbc.Driver
spring.shardingsphere.datasource.m1.username=root
spring.shardingsphere.datasource.m1.password=12345
spring.shardingsphere.datasource.m1.url=jdbc:mysql://localhost:3306/temporary?characterEncoding=utf-8&useSSL=false
# 从数据源
spring.shardingsphere.datasource.s0.type=com.alibaba.druid.pool.DruidDataSource
spring.shardingsphere.datasource.s0.driver-class-name=com.mysql.jdbc.Driver
spring.shardingsphere.datasource.s0.username=root
spring.shardingsphere.datasource.s0.password=12345
spring.shardingsphere.datasource.s0.url=jdbc:mysql://localhost:3307/temporary?characterEncoding=utf-8&useSSL=false
#指定表主键生成策略及唯一性，主要用来进行生成id
spring.shardingsphere.sharding.tables.student.key-generator.column=id
spring.shardingsphere.sharding.tables.student.key-generator.type=SNOWFLAKE
#设置主从配置，都映射到ds0的名称上
#声明主数据源的配置是m1
spring.shardingsphere.sharding.master-slave-rules.ds0.master-data-source-name=m1
#声明从数据源的配置时s0
spring.shardingsphere.sharding.master-slave-rules.ds0.slave-data-source-names=s0
# 指定数据最终映射到哪些表上
# 配置从数据库的数据节点,次节点表示包含主从数据源的数据节点映射，需要注释掉原来主数据源的节点配置
spring.shardingsphere.sharding.tables.student.actual-data-nodes=ds0.student$->{1..2}
# 指定数据映射到不同表上的策略规则
# 指定逻辑插入方式分片策略，根据id映射到student1或student2表上，属于水平分表
spring.shardingsphere.sharding.tables.student.table-strategy.inline.sharding-column=id
spring.shardingsphere.sharding.tables.student.table-strategy.inline.algorithm-expression=student$->{id % 2 +1}
#打开日志
spring.shardingsphere.props.sql.show=true
# 允许bean覆盖，防止bean和springboot注入冲突
spring.main.allow-bean-definition-overriding=true
# 日志级别设置
logging.level.root=info
logging.level.org.springframework.web=info
logging.level.com.example.sharding=debug
logging.level.druid.sql=debug
3. Entity class &dao development
Student
@Data
public class Student {
private Integer id;
private String name;
private String sSex;
}
StudentDao
@Mapper
@Component
public interface StudentDao {
@Insert(" insert into student(name,s_sex) values (#{name},#{sSex}) ")
int insertStudent(@Param("name") String name, @Param("sSex") String sSex);
@Select(" select * from student where id = #{id}")
Student selectById(@Param("id") Integer id);
}
4. Testing
ShardingApplicationTests
@SpringBootTest
class ShardingApplicationTests {
@Autowired
StudentDao studentDao;
@Test
void contextLoads() {
studentDao.insertStudent("马武","男");
}
@Test
void testGetById() {
Student student = studentDao.selectById(8);
System.out.println(student.getSSex());
}
}
5. Running results:
