SpringBoot+Dynamic多数据源动态切换

最近做了个小模块，需求就是项目同时读取三个数据库，操作数据。并不是分库分表，只用定时跑，不需要对外提供接口。

技术选型：SpringBoot + Mybatis Plus(Mybatis) + Dynamic

1. 用MyBatis Plus 生成mapper、xml、service，生成方法。

2. 引用核心jar包

<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>3.2.0</version>
</dependency>
<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>dynamic-datasource-spring-boot-starter</artifactId>
    <version>2.4.2</version>
</dependency>

3. yml文件配置（有需要连接池配置的可以自己加）

spring:
  datasource:
    #配置hikari连接池
    hikari:
      minimum-idle: 4
      maximum-pool-size: 16
      connection-timeout: 10000
      idle-timeout: 30000
      connection-init-sql: set names utf8mb4
    #动态数据源配置
    dynamic:
      #主数据源
      primary: business
      datasource:
        #数据源1
        business:
          driver-class-name: com.mysql.cj.jdbc.Driver
          url: jdbc:mysql://localhost:3306/db_business?useUnicode=true&characterEncoding=utf-8
          username: ****
          password: ****
        #数据源2
        user:
          driver-class-name: com.mysql.cj.jdbc.Driver
          url: jdbc:mysql://localhost:3306/db_user?useUnicode=true&characterEncoding=utf-8
          username: ****
          password: ****
        #数据源3
        order:
          driver-class-name: com.mysql.cj.jdbc.Driver
          url: jdbc:mysql://localhost:3306/db_order?useUnicode=true&characterEncoding=utf-8
          username: ****
          password: ****

4. 在Service层加DS注解（注意：这个注解要加到mapper.xml文件对应的dao接口层，会报加载失败异常）

@Service
@DS(value = "user")
public class UserServiceImpl extends ServiceImpl<UserMapper, UserInfo>
        implements UserService {

}

bussines, order...库配置是一样的

5. 启动类注解

@MapperScan("com.**.dao")
@ComponentScan(value = "com.**")
@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class})
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
    
}

6. 启动项目，看日志输出了如下信息，表示配置成功：

2019-12-16 20:50:52.565  INFO 12896 --- [     main] com.zaxxer.hikari.HikariDataSource       : business - Starting...
2019-12-16 20:50:53.611  INFO 12896 --- [     main] com.zaxxer.hikari.HikariDataSource       : business - Start completed.
2019-12-16 20:50:53.611  INFO 12896 --- [     main] com.zaxxer.hikari.HikariDataSource       : user - Starting...
2019-12-16 20:50:54.100  INFO 12896 --- [     main] com.zaxxer.hikari.HikariDataSource       : user - Start completed.
2019-12-16 20:50:54.100  INFO 12896 --- [     main] com.zaxxer.hikari.HikariDataSource       : order - Starting...
2019-12-16 20:50:54.607  INFO 12896 --- [     main] com.zaxxer.hikari.HikariDataSource       : order - Start completed.
2019-12-16 20:50:54.608  INFO 12896 --- [     main] c.b.d.d.DynamicRoutingDataSource         : 初始共加载 3 个数据源
2019-12-16 20:50:54.608  INFO 12896 --- [     main] c.b.d.d.DynamicRoutingDataSource         : 动态数据源-加载 business 成功
2019-12-16 20:50:54.608  INFO 12896 --- [     main] c.b.d.d.DynamicRoutingDataSource         : 动态数据源-加载 user 成功
2019-12-16 20:50:54.608  INFO 12896 --- [     main] c.b.d.d.DynamicRoutingDataSource         : 动态数据源-加载 order 成功
2019-12-16 20:50:54.609  INFO 12896 --- [     main] c.b.d.d.DynamicRoutingDataSource         : 当前的默认数据源是单数据源，数据源名为 business