一、修改配置文件 application.yml

server:
  port: 8001
spring:
  #定义多数据源
  datasource-test1:
    driver-class-name: com.mysql.jdbc.Driver
    jdbc-url: jdbc:mysql://127.0.0.1:3306/test1?useUnicode=true&characterEncoding=utf-8&useSSL=false
    username: root
    password: root
    dbcp2:
      #验证连接的有效性
      test-while-idle: true
      #验证语句
      validation-query: SELECT 1
      #空闲连接回收的时间间隔,与test-while-idle一起使用,设置5分钟
      time-between-eviction-runs-millis: 300000
      #连接池空闲连接的有效时间 ,设置30分钟
      soft-min-evictable-idle-time-millis: 1800000
    hikari:
      #一个连接的生命时长(毫秒),超时而且没被使用则被释放(retired)
      #      max-lifetime: 60000
      #连接池中允许的最大连接数
      maximum-pool-size: 15
      #<!-- 生效超时 -->
      validation-timeout: 3000
      #连接只读数据库时配置为true, 保证安全
      read-only: false
      #等待连接池分配连接的最大时长(毫秒),超过这个时长还没可用的连接则发生SQLException
      connection-timeout: 60000
      #一个连接idle状态的最大时长(毫秒),超时则被释放(retired)
      idle-timeout: 60000
      # 一个连接的生命时长(毫秒),超时而且没被使用则被释放(retired),缺省:30分钟,建议设置比数据库超时时长少30秒,参考MySQLwait_timeout参数(show variables like '%timeout%';)
      max-lifetime: 120000
  datasource-test2:
    driver-class-name: com.mysql.jdbc.Driver
    jdbc-url: jdbc:mysql://127.0.0.1:3306/test2?useUnicode=true&characterEncoding=utf-8&useSSL=false
    username: root
    password: root
    dbcp2:
      #验证连接的有效性
      test-while-idle: true
      #验证语句
      validation-query: SELECT 1
      #空闲连接回收的时间间隔,与test-while-idle一起使用,设置5分钟
      time-between-eviction-runs-millis: 300000
      #连接池空闲连接的有效时间 ,设置30分钟
      soft-min-evictable-idle-time-millis: 1800000
    hikari:
      #一个连接的生命时长(毫秒),超时而且没被使用则被释放(retired)
      #      max-lifetime: 60000
      #连接池中允许的最大连接数
      maximum-pool-size: 15
      #<!-- 生效超时 -->
      validation-timeout: 3000
      #连接只读数据库时配置为true, 保证安全
      read-only: false
      #等待连接池分配连接的最大时长(毫秒),超过这个时长还没可用的连接则发生SQLException
      connection-timeout: 60000
      #一个连接idle状态的最大时长(毫秒),超时则被释放(retired)
      idle-timeout: 60000
      # 一个连接的生命时长(毫秒),超时而且没被使用则被释放(retired),缺省:30分钟,建议设置比数据库超时时长少30秒,参考MySQLwait_timeout参数(show variables like '%timeout%';)
      max-lifetime: 120000
#mybatis配置
mybatis:
  config-location: classpath:mybatis/mybatis-config.xml
  

二、创建config文件夹

1.创建 DataSourceConfig

package com.majiameng.config;
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;
/**
 * 数据源配置
 */
@Configuration
public class DataSourceConfig {
    @Bean(name="datasourceTest1")
    @ConfigurationProperties(prefix = "spring.datasource-test1")
    public DataSource datasourceTest1() {
        return DataSourceBuilder.create().build();
    }
    @Bean(name="datasourceTest2")
    @ConfigurationProperties(prefix = "spring.datasource-test2")
    public DataSource datasourceTest2() {
        return DataSourceBuilder.create().build();
    }
}

2.创建 MybatisTest1Config

package com.majiameng.config;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;
import javax.sql.DataSource;
/**
 * 定义test1数据源
 */
@Configuration
@MapperScan(basePackages = {"com.majiameng.mapper.test1"},sqlSessionFactoryRef = "sqlSessionFactoryTest1")
public class MybatisTest1Config {
    @Autowired
    @Qualifier(value="datasourceTest1")
    private DataSource test1;
    @Bean
    public SqlSessionFactory sqlSessionFactoryTest1() throws Exception {
        SqlSessionFactoryBean factory = new SqlSessionFactoryBean();
        factory.setDataSource(test1);
        //指定mapper位置
        factory.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mybatis/mapper/test1/*.xml"));
        return factory.getObject();
    }
    @Bean
    public SqlSessionTemplate sqlSessionTemplateTest1() throws Exception {
        SqlSessionTemplate template = new SqlSessionTemplate(sqlSessionFactoryTest1());
        return template;
    }
    @Bean(name = "transactionManagerTest1")
    public PlatformTransactionManager transactionManagerTest1() {
        return new DataSourceTransactionManager(test1);
    }
}

3.创建 MybatisTest2Config

package com.majiameng.config;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;
import javax.sql.DataSource;
/**
 * 定义test2数据源
 */
@Configuration
@MapperScan(basePackages = {"com.majiameng.mapper.test2"},sqlSessionFactoryRef = "sqlSessionFactoryTest2")
public class MybatisTest2Config {
    @Autowired
    @Qualifier(value="datasourceTest2")
    private DataSource test2;
    @Bean
    public SqlSessionFactory sqlSessionFactoryTest2() throws Exception {
        SqlSessionFactoryBean factory = new SqlSessionFactoryBean();
        factory.setDataSource(test2);
        //指定mapper位置
        factory.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mybatis/mapper/test2/*.xml"));
        return factory.getObject();
    }
    @Bean
    public SqlSessionTemplate sqlSessionTemplateTest2() throws Exception {
        SqlSessionTemplate template = new SqlSessionTemplate(sqlSessionFactoryTest2());
        return template;
    }
    @Bean(name = "transactionManagerTest2")
    public PlatformTransactionManager transactionManagerTest2() {
        return new DataSourceTransactionManager(test2);
    }
}

三、然后对应创建包

com.majiameng.mapper.test1;
com.majiameng.mapper.test2;

resources.mybatis.mapper.test1
resources.mybatis.mapper.test2

四、在启动类上加注解,启动事务

//@ServletComponentScan 注解后,Servlet、Filter、Listener 可以直接通过 @WebServlet、@WebFilter、@WebListener 注解自动注册
@ServletComponentScan
//事务管理注解
@EnableTransactionManagement

五、千万切记:检查连接池配置是否生效

  按照上面四步骤做完,你就以为OK了吗?NO,NO,NO,数据库连接多了,立即报错:
HikariPool-1 - Connection is not available, request timed out after 30000ms...
(数据库连接池请求超时)

  这都是本博主踩过的坑啊!!! 原因是application.yml里连接池配置未生效,默认Hikari的配置了。

检查办法:
  MybatisTest1Config类的sqlSessionFactoryTest1()方法里第一行,就打印一下DataSource test1的连接池配置信息!部分示例代码如下:

public SqlSessionFactory sqlSessionFactoryTest1() throws Exception {
        HikariDataSource hds = (HikariDataSource ) test1;
        System.out.println(hds.getConnectionTimeout()); //打印连接超时时间
        ....... //打印hds的其他连接池配置信息,我就不写了


        SqlSessionFactoryBean factory = new SqlSessionFactoryBean();
        factory.setDataSource(test1);
        //指定mapper位置
        factory.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mybatis/mapper/test1/*.xml"));
        return factory.getObject();
    }

解决办法:

public SqlSessionFactory sqlSessionFactoryTest1() throws Exception {
        HikariDataSource hds = (HikariDataSource ) test1;
        hds.setConnectionTimeout(600000); //设置连接超时时间
        ....... //设置hds的其他连接池配置信息,我就不写了


        SqlSessionFactoryBean factory = new SqlSessionFactoryBean();
        factory.setDataSource(test1);
        //指定mapper位置
        factory.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mybatis/mapper/test1/*.xml"));
        return factory.getObject();
    }

最后

  多数据源场景中,如果你用到了SqlSession统一提交,那么你在获取SqlSession使用时,可能会遇到报错:mapped statements collection does not contain......

  是因为默认用的是主数据源的SqlSessionFactory,获取的是主数据源的SqlSession,如果你用它调用别的数据源的mapper接口,肯定报错找不到啊!

  如何解决?等我抽时间写一篇《Mybatis多数据源下,SqlSessionFactory的动态切换》

  若有帮助,请点赞+关注!

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