Java中SringBoot服务连接多个MySQL数据源案例实战

1.场景

A服务（供应商）有一套自己的数据库db1；B服务（二次开发）也有一套自己的数据库db2；从B服务查询db1中的一些数据，需要B服务同时链接2个数据库源。

2.取消默认的单数据源配置

修改启动类的@SpringBootApplication注解，（将org.example.db.**.mapper替换为自己项目的mapper文件目录）

@SpringBootApplication(exclude={DataSourceAutoConfiguration.class})
@MapperScan({"org.example.db1.**.mapper","org.example.db1.**.mapper"})
public class TestApplication{...
}

3.自定义多数据源配置文件

在application.properties 文件（或nacos配置文件）中配置以下数据库连接源：

spring:# 数据源配置datasource:db1:jdbc-url: xxxxxxxxxxxxxxusername: xxxxxxxxxxxxxxpassword: xxxxxxxxxxxxxxtype: com.alibaba.druid.pool.DruidDataSourcedriver-class-name: com.mysql.cj.jdbc.Driverdb2:jdbc-url: xxxxxxxxxxxxxxusername: xxxxxxxxxxxxxxpassword: xxxxxxxxxxxxxxtype: com.alibaba.druid.pool.DruidDataSourcedriver-class-name: com.mysql.cj.jdbc.Driver

4.自定义多数据源配置类

1.DB1Config.java

将org.example.db1.**.mapper替换为自己项目的mapper文件目录

import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.annotation.FieldStrategy;
import com.baomidou.mybatisplus.core.MybatisConfiguration;
import com.baomidou.mybatisplus.core.config.GlobalConfig;
import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
import com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean;
import org.apache.ibatis.plugin.Interceptor;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;import javax.sql.DataSource;@Configuration
@MapperScan(basePackages = "org.example.db1.**.mapper",sqlSessionFactoryRef = "db1SqlSessionFactory")
public class DB1Config {@Primary@Bean(name = "db1DataSource")@ConfigurationProperties(prefix = "spring.datasource.db1")public DataSource initDataSource(){return DataSourceBuilder.create().build();}@Primary@Bean(name = "db1SqlSessionFactory")public SqlSessionFactory initSqlSessionFactory(@Qualifier("db1DataSource") DataSource dataSource) throws Exception {MybatisSqlSessionFactoryBean bean = new MybatisSqlSessionFactoryBean();bean.setDataSource(dataSource);GlobalConfig globalConfig = new GlobalConfig();globalConfig.setDbConfig(new GlobalConfig.DbConfig().setUpdateStrategy(FieldStrategy.IGNORED));bean.setGlobalConfig(globalConfig);MybatisConfiguration mybatisConfiguration = new MybatisConfiguration();mybatisConfiguration.setMapUnderscoreToCamelCase(false);bean.setConfiguration(mybatisConfiguration);bean.setPlugins(new Interceptor[]{mybatisPlusInterceptor()});SqlSessionFactory sessionFactory = bean.getObject();org.apache.ibatis.session.Configuration configuration = sessionFactory.getConfiguration();configuration.setMapUnderscoreToCamelCase(false);return sessionFactory;}@Primary@Bean(name = "db1mybatisPlusInterceptor")public Interceptor mybatisPlusInterceptor() {MybatisPlusInterceptor mybatisPlusInterceptor = new MybatisPlusInterceptor();mybatisPlusInterceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));return mybatisPlusInterceptor;}@Primary@Bean(name = "db1DataSourceTransactionManager")public DataSourceTransactionManager initDataSourceTransactionManager(@Qualifier("db1DataSource") DataSource dataSource){return new DataSourceTransactionManager(dataSource);}@Primary@Bean(name = "db1SqlSessionTemplate")public SqlSessionTemplate initSqlSessionTemplate(@Qualifier("db1SqlSessionFactory")SqlSessionFactory sqlSessionFactory){return new SqlSessionTemplate(sqlSessionFactory);}}

2.DB2Config.java

数据库 db2 的配置类要将 @Primary 注解去掉

import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.annotation.FieldStrategy;
import com.baomidou.mybatisplus.core.MybatisConfiguration;
import com.baomidou.mybatisplus.core.config.GlobalConfig;
import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
import com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean;
import org.apache.ibatis.plugin.Interceptor;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;import javax.sql.DataSource;
@Configuration
@MapperScan(basePackages = "org.example.db2.**.mapper",sqlSessionFactoryRef = "db2SqlSessionFactory")
public class DB2Config {@Bean(name = "db2DataSource")@ConfigurationProperties(prefix = "spring.datasource.db2")public DataSource initDataSource(){return DataSourceBuilder.create().build();}@Bean(name = "db2SqlSessionFactory")public SqlSessionFactory initSqlSessionFactory(@Qualifier("db2DataSource") DataSource dataSource) throws Exception {MybatisSqlSessionFactoryBean bean = new MybatisSqlSessionFactoryBean();bean.setDataSource(dataSource);GlobalConfig globalConfig = new GlobalConfig();globalConfig.setDbConfig(new GlobalConfig.DbConfig().setUpdateStrategy(FieldStrategy.IGNORED));bean.setGlobalConfig(globalConfig);MybatisConfiguration mybatisConfiguration = new MybatisConfiguration();mybatisConfiguration.setMapUnderscoreToCamelCase(false);bean.setConfiguration(mybatisConfiguration);bean.setPlugins(new Interceptor[]{mybatisPlusInterceptor()});SqlSessionFactory sessionFactory = bean.getObject();org.apache.ibatis.session.Configuration configuration = sessionFactory.getConfiguration();configuration.setMapUnderscoreToCamelCase(false);return sessionFactory;}@Bean(name = "db2mybatisPlusInterceptor")public Interceptor mybatisPlusInterceptor() {MybatisPlusInterceptor mybatisPlusInterceptor = new MybatisPlusInterceptor();mybatisPlusInterceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));return mybatisPlusInterceptor;}@Bean(name = "db2DataSourceTransactionManager")public DataSourceTransactionManager initDataSourceTransactionManager(@Qualifier("db2DataSource") DataSource dataSource){return new DataSourceTransactionManager(dataSource);}@Bean(name = "db2SqlSessionTemplate")public SqlSessionTemplate initSqlSessionTemplate(@Qualifier("db2SqlSessionFactory")SqlSessionFactory sqlSessionFactory){return new SqlSessionTemplate(sqlSessionFactory);}
}

5.启动项目，测试操作多数据源

项目启动后，控制台中看到以下内容即为配置成功

HikariPool-1 - Starting…
HikariPool-1 - Start completed.
HikariPool-2 - Starting…
HikariPool-2 - Start completed.