目录
- 1. Dynamic-Datasource实现多JDBC数据源配置
- 1.1 特性
- 1.2 Mysql数据准备
- 2.2 通过Dynamic-Datasource实现多JDBC数据源
- 2.2.1 pom.xml依赖
- 2.2.2 application.properties配置
- 2.2.3 使用@DS注解选择DataSource
- 2.2.4 使用@Transactional + @DSTransactional实现事务
- 2.3 动态数据源测试
- 2.3.1 创建User类
- 2.3.2 Mapper接口实现
- 2.3.3 Service实现
- 2.3.4 测试
- 2.4 removeDataSource删除DataSource
1. Dynamic-Datasource实现多JDBC数据源配置
1.1 特性
- 提供本地多数据源事务方案。由AOP实现
- 支持数据源分组,适用于多种场景,如多库读写分离、一主多从(实现了数据库负载均衡算法)、混合模式
- 提供自定义数据源来源方案(如全从数据库加载)
- 提供项目启动后动态增加移除数据源方案
- 支持数据库敏感配置信息加密(可自定义)ENC()
- 支持每个数据库独立初始化表结构schema和数据库database
- 支持无数据源启动,支持懒加载数据源(需要的时候再创建连接)
- 支持自定义注解,需继承DS(3.2.0+)
- 提供并简化对Druid、HikariCp、BeeCp、Dbcp2的快速集成
- 提供对Mybatis-Plus、Quartz、ShardingJdbc、P6sy、Jndi等组件的集成方案
- 提供Mybatis环境下的纯读写分离方案
- 提供使用spel动态参数解析数据源方案。内置spel、session、header,支持自定义
- 支持多层数据源嵌套切换。(ServiceA >>> ServiceB >>> ServiceC)
- 支持Seata分布式事务
1.2 Mysql数据准备
分别创建read_db.user和write_db.user,并向read_db.user写入数据
mysql> create database read_db;
Query OK, 1 row affected (0.14 sec)
mysql> create database write_db;
Query OK, 1 row affected (0.01 sec)
mysql> create table read_db.user (
-> id bigint(20) auto_increment not null comment '主键ID',
-> name varchar(30) null default null comment '姓名',
-> primary key (id)
-> );
Query OK, 0 rows affected, 1 warning (0.29 sec)
mysql>
mysql> insert into read_db.user (id, name) values
-> (1, 'read_name1'),
-> (2, 'read_name2'),
-> (3, 'read_name3'),
-> (4, 'read_name4'),
-> (5, 'read_name5');
Query OK, 5 rows affected (0.16 sec)
Records: 5 Duplicates: 0 Warnings: 0
mysql>
mysql> create table write_db.user (
-> id bigint(20) auto_increment not null comment '主键ID',
-> name varchar(30) null default null comment '姓名',
-> primary key (id)
-> );
Query OK, 0 rows affected, 1 warning (0.04 sec)
mysql>
2.2 通过Dynamic-Datasource实现多JDBC数据源
2.2.1 pom.xml依赖
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.31</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.2.15</version>
</dependency>
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>dynamic-datasource-spring-boot-starter</artifactId>
<version>3.5.2</version>
</dependency>
可以看到自动添加了spring-boot-starter-jdbc、spring-boot-starter-aop依赖
2.2.2 application.properties配置
通过dynamic方式,指定了datasource1和datasource2两个DataSource
spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
# 设置默认的数据源。默认是master
spring.datasource.dynamic.primary=datasource1
# 严格匹配数据源, 默认false。true表示未匹配到指定数据源时抛异常, false表示使用默认数据源
spring.datasource.dynamic.strict=true
# 用于读的数据库
spring.datasource.dynamic.datasource.datasource1.url=jdbc:mysql://192.168.28.12:3306/read_db
spring.datasource.dynamic.datasource.datasource1.username=root
spring.datasource.dynamic.datasource.datasource1.password=Root_123
spring.datasource.dynamic.datasource.datasource1.driver-class-name=com.mysql.cj.jdbc.Driver
# 用于写的数据库
spring.datasource.dynamic.datasource.datasource2.url=jdbc:mysql://192.168.28.12:3306/write_db
spring.datasource.dynamic.datasource.datasource2.username=root
spring.datasource.dynamic.datasource.datasource2.password=Root_123
spring.datasource.dynamic.datasource.datasource2.driver-class-name=com.mysql.cj.jdbc.Driver
2.2.3 使用@DS注解选择DataSource
可以在Service的类或方法上(优先级更高)使用@DS注解选择DataSource
2.2.4 使用@Transactional + @DSTransactional实现事务
可以在Service的类或方法上(优先级更高)使用@Transactional实现事务。对异常的捕获后,通过TransactionAspectSupport.currentTransactionStatus().setRollbackOnly()
进行手动回滚
@Transactional注解会让@DS的多数据源切换失效,虽然可以通过@Transactional(propagation = Propagation.REQUIRES_NEW)
开启一个内部子事务来使@DS切换数据源,但是大部分场景不适用
@DSTransactional能和@DS多数据源切换配合使用,@DSTransactional注解最好使用在方法上(类似好像不生效),@DSTransactional注解不能对异常进行捕获手动回滚,只能自动回滚然后抛出异常
2.3 动态数据源测试
2.3.1 创建User类
package com.hh.springboottest.myController;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;
@NoArgsConstructor
@AllArgsConstructor
@Data
@ToString
public class User {
private Long id;
private String name;
}
2.3.2 Mapper接口实现
package com.hh.springboottest.mapper;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.hh.springboottest.myController.User;
import org.apache.ibatis.annotations.Mapper;
@Mapper
public interface UserMapper extends BaseMapper<User> {
}
2.3.3 Service实现
Service接口实现
package com.hh.springboottest.service;
import com.hh.springboottest.myController.User;
public interface UserService {
public User getUser(Long id);
public void saveMultiUser();
}
ServiceImpl实现类。说明如下:
- @DS(“datasource1”)注解,让userMapper.selectById使用了datasource1数据源
- @DS(“datasource2”)注解,让userMapper.insert使用了datasource2数据源
- @Transactional注解,当userMapper.insert(user1)执行成功,userMapper.insert(user2)执行失败,会回滚userMapper.insert(user1)的操作
package com.hh.springboottest.service.impl;
import com.baomidou.dynamic.datasource.annotation.DS;
import com.hh.springboottest.mapper.UserMapper;
import com.hh.springboottest.myController.User;
import com.hh.springboottest.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
@Service
public class UserServiceImpl implements UserService {
@Autowired
UserMapper userMapper;
@DS("datasource1")
@Override
public User getUser(Long id) {
return userMapper.selectById(id);
}
@Transactional
@DS("datasource2")
@Override
public void saveMultiUser() {
User user2 = new User(2L, "write_name2");
userMapper.insert(user2);
User user3 = new User(3L, "write_name3");
userMapper.insert(user3);
}
}
2.3.4 测试
package com.hh.springboottest;
import com.hh.springboottest.myController.User;
import com.hh.springboottest.service.UserService;
import lombok.extern.slf4j.Slf4j;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
@Slf4j
@SpringBootTest
public class MyApplicationTest {
@Autowired
UserService userService;
@Test
public void dynamicDataSourceTest() {
User user = userService.getUser(1L);
log.info("获取到的用户为:{}", user);
userService.saveMultiUser();
}
}
运行程序,结果如下:
2022-11-24 09:16:15.733 INFO 33760 --- [ main] com.hh.springboottest.MyApplicationTest : 获取到的用户为:User(id=1, name=read_name1)
2022-11-24 09:16:15.857 INFO 33760 --- [ionShutdownHook] c.b.d.d.DynamicRoutingDataSource : dynamic-datasource start closing ....
2022-11-24 09:16:15.861 INFO 33760 --- [ionShutdownHook] com.alibaba.druid.pool.DruidDataSource : {dataSource-1} closing ...
2022-11-24 09:16:15.866 INFO 33760 --- [ionShutdownHook] com.alibaba.druid.pool.DruidDataSource : {dataSource-1} closed
2022-11-24 09:16:15.866 INFO 33760 --- [ionShutdownHook] com.alibaba.druid.pool.DruidDataSource : {dataSource-2} closing ...
2022-11-24 09:16:15.867 INFO 33760 --- [ionShutdownHook] com.alibaba.druid.pool.DruidDataSource : {dataSource-2} closed
2022-11-24 09:16:15.867 INFO 33760 --- [ionShutdownHook] c.b.d.d.DynamicRoutingDataSource : dynamic-datasource all closed success,bye
同时查看write_db.user表,数据如下:
mysql> select * from write_db.user;
+----+--------------+
| id | name |
+----+--------------+
| 1 | write_name1 |
| 2 | write_name2 |
| 3 | write_name3 |
+----+--------------+
3 rows in set (0.11 sec)
mysql>
2.4 removeDataSource删除DataSource
通过DynamicRoutingDataSource的removeDataSource方法删除DataSource
package com.hh.springboottest.service.impl;
import com.baomidou.dynamic.datasource.DynamicRoutingDataSource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import javax.sql.DataSource;
@Service
public class DataSourceServiceImpl implements DataSourceService {
@Autowired
DataSource dataSource;
public void removeDataSource(String dataSourceName) {
DynamicRoutingDataSource dynamicRoutingDataSource =
(DynamicRoutingDataSource) dataSource;
dynamicRoutingDataSource.removeDataSource(dataSourceName);
}
}