文章目录
- 1、application.yml
- 2、shardingsphere.yaml
- 3、创建实体类 User
- 4、创建 UserMapper
- 5、添加依赖
- 6、读写分离测试
- 7、事务测试
我们的主从复制已经提前搭建好： mysql-搭建主从复制：https://blog.csdn.net/m0_65152767/article/details/142214434
1、application.yml
spring:
datasource:
# driver-class-name: com.mysql.cj.jdbc.Driver
# 驱动类：使用shardingjdbc提供的驱动类
driver-class-name: org.apache.shardingsphere.driver.ShardingSphereDriver
# username: root
# password: 123456
# url: jdbc:mysql://192.168.74.148:3306/mydb2?serverTimezone=GMT%2B8
url: jdbc:shardingsphere:classpath:shardingsphere.yaml
2、shardingsphere.yaml
# 模式配置
mode:
# shardingjdbc：使用的是单机模式
type: Standalone
repository:
type: JDBC
# 数据源配置
dataSources:
write_ds:
dataSourceClassName: com.zaxxer.hikari.HikariDataSource
driverClassName: com.mysql.cj.jdbc.Driver
jdbcUrl: jdbc:mysql://192.168.74.148:3306/mydb2
username: root
password: 123456
read_ds_0:
dataSourceClassName: com.zaxxer.hikari.HikariDataSource
driverClassName: com.mysql.cj.jdbc.Driver
jdbcUrl: jdbc:mysql://192.168.74.148:3316/mydb2
username: root
password: 123456
# 读写分离配置：指定读交给哪个数据源 写交给哪个
rules:
- !READWRITE_SPLITTING
dataSources:
readwrite_ds:
writeDataSourceName: write_ds
readDataSourceNames:
- read_ds_0
transactionalReadQueryStrategy: PRIMARY # 事务内读请求的路由策略，可选值：PRIMARY（路由至主库）、FIXED（同一事务内路由至固定数据源）、DYNAMIC（同一事务内路由至非固定数据源）。默认值：DYNAMIC
# 配置读操作的负载均衡策略
loadBalancerName: random
loadBalancers:
random:
type: RANDOM
round_robin:
type: ROUND_ROBIN
weight:
type: WEIGHT
props:
read_ds_0: 1
# 输出sql：
props:
# 打印 sharding 的sql日志
sql-show: true
3、创建实体类 User
package com.atguigu.sharding.jdbc.demo.bean;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.Data;
@Data
@TableName(value = "t_user")
public class User {
private Long id;
private String name;
}
4、创建 UserMapper
package com.atguigu.sharding.jdbc.demo.mapper;
import com.atguigu.sharding.jdbc.demo.bean.User;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import org.apache.ibatis.annotations.Mapper;
@Mapper
public interface UserMapper extends BaseMapper<User> {
}
5、添加依赖
<dependencies>
<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>
<!--操作数据库-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.30</version>
</dependency>
<!--mybatisPlus-->
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>3.5.3.1</version>
</dependency>
<!--lombok-->
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.apache.shardingsphere</groupId>
<artifactId>shardingsphere-jdbc-core</artifactId>
<version>5.4.0</version>
</dependency>
<!--兼容jdk17和spring boot3-->
<dependency>
<groupId>org.yaml</groupId>
<artifactId>snakeyaml</artifactId>
<version>1.33</version>
</dependency>
<dependency>
<groupId>org.glassfish.jaxb</groupId>
<artifactId>jaxb-runtime</artifactId>
<version>2.3.8</version>
</dependency>
</dependencies>
6、读写分离测试
package com.atguigu.sharding.jdbc.demo;
import com.atguigu.sharding.jdbc.demo.bean.User;
import com.atguigu.sharding.jdbc.demo.mapper.UserMapper;
import jakarta.annotation.Resource;
import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;
@SpringBootTest
class ShardingJdbcDemoApplicationTests {
@Resource
UserMapper userMapper;
@Test
void contextLoads() {
for (int i = 0; i < 3; i++) {
//User user1 = userMapper.selectById(1);
userMapper.selectList(null).forEach(System.out::println);
}
}
}
2024-09-24T10:10:43.199+08:00 INFO 1436 --- [ main] ShardingSphere-SQL : Logic SQL: SELECT id,name FROM t_user
2024-09-24T10:10:43.199+08:00 INFO 1436 --- [ main] ShardingSphere-SQL : Actual SQL: read_ds_0 ::: SELECT id,name FROM t_user
User(id=1, name=张三)
User(id=2, name=李四)
User(id=3, name=3316)
2024-09-24T10:10:43.277+08:00 INFO 1436 --- [ main] ShardingSphere-SQL : Logic SQL: SELECT id,name FROM t_user
2024-09-24T10:10:43.277+08:00 INFO 1436 --- [ main] ShardingSphere-SQL : Actual SQL: read_ds_0 ::: SELECT id,name FROM t_user
User(id=1, name=张三)
User(id=2, name=李四)
User(id=3, name=3316)
2024-09-24T10:10:43.282+08:00 INFO 1436 --- [ main] ShardingSphere-SQL : Logic SQL: SELECT id,name FROM t_user
2024-09-24T10:10:43.282+08:00 INFO 1436 --- [ main] ShardingSphere-SQL : Actual SQL: read_ds_0 ::: SELECT id,name FROM t_user
User(id=1, name=张三)
User(id=2, name=李四)
User(id=3, name=3316)
7、事务测试
transactionalReadQueryStrategy: PRIMARY
事务内读请求的路由策略，可选值：
PRIMARY（路由至主库）
FIXED（同一事务内路由至固定数据源）
DYNAMIC（同一事务内路由至非固定数据源）。默认值：DYNAMIC
测试1：
不添加@Transactional：insert对主库操作，select对从库操作
测试2：
添加@Transactional：则insert和select按照transactionalReadQueryStrategy的配置执行
/**
* 事务测试
*/
@Transactional//开启事务
@Test
public void testTrans(){
User user = new User();
user.setUname("铁锤");
userMapper.insert(user);
List<User> users = userMapper.selectList(null);
}
注意： 在JUnit环境下的@Transactional注解，默认情况下就会对事务进行回滚（即使在没加注解@Rollback，也会对事务回滚）
常见错误
ShardingSphere-JDBC远程连接的方式默认的密码加密规则是：mysql_native_password
因此需要在服务器端修改服务器的密码加密规则，如下：
ALTER USER 'root'@'%' IDENTIFIED WITH mysql_native_password BY '123456';
