ymal文件针对mysql举例

# database
spring:
  application:
    name: testDBs
  flyway:
    enabled: false
  datasource:
    data1:
      driver-class-name: com.mysql.jdbc.Driver
      type: com.zaxxer.hikari.HikariDataSource
      jdbc-url: jdbc:mysql:#########
      username: #########
      password: #########
    data2:
      driver-class-name: com.mysql.jdbc.Driver
      type: com.zaxxer.hikari.HikariDataSource
      jdbc-url: jdbc:mysql:###########
      username: ########
      password: ###########
    hikari:
      pool-name: Hikari
      auto-commit: false

两个DataSource配置：
第一个：

package com.****.****.****.****.config;


import com.baomidou.mybatisplus.core.MybatisConfiguration;
import org.apache.ibatis.logging.stdout.StdOutImpl;
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.Qualifier;
import org.springframework.beans.factory.annotation.Value;
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.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;

import javax.sql.DataSource;


//@ConditionalOnProperty(prefix = "spring.datasource.apidb", name = "enabled", havingValue = "true")//注解@ConditionalOnProperty，这个注解能够控制某个configuration是否生效，这里的配置不要动，修改在properties文件中，往上看
@Configuration
@EnableTransactionManagement
@MapperScan(basePackages = "com.*****.****.*****.****.dao.mapper.data1", sqlSessionTemplateRef = "slaveSqlSessionTemplate")
public class DataSource1Config {

    @Value(value = "${mybatis-plus.sql.show}")
    private boolean isshowSql;
    @Bean("slaveDataSource")
    @ConfigurationProperties(prefix = "spring.datasource.data1")
    public DataSource slaveDataSource() {
        return DataSourceBuilder.create().build();
    }

    @Bean(name = "slaveSqlSessionFactory")
    public SqlSessionFactory slaveSqlSessionFactory(@Qualifier("slaveDataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        //设置slave数据源mapper文件路径
        bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath*:mapper/data1/*.xml"));
        MybatisConfiguration config = new MybatisConfiguration();
        // 开启javaBean 成员变量名映射为映射到数据库列名的时候，驼峰命名法到下划线分割命名法则的自动转换功能（）
        config.setMapUnderscoreToCamelCase(true);
        //增加对mybatis自带分页的支持
        config.addInterceptor(new PaginationInterceptor());
        config.setCacheEnabled(false);
        bean.setConfiguration(config);
        if(isshowSql) {
            MybatisConfiguration mybatisConfiguration = new MybatisConfiguration();
            mybatisConfiguration.setLogImpl(StdOutImpl.class);
        }
        return bean.getObject();
    }

    @Bean(name = "slaveTransactionManager")
    public DataSourceTransactionManager slaveTransactionManager(@Qualifier("slaveDataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }

    @Bean(name = "slaveSqlSessionTemplate")
    public SqlSessionTemplate slaveSqlSessionTemplate(@Qualifier("slaveSqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplate(sqlSessionFactory);
    }
    @Bean
    public PaginationInterceptor paginationInterceptor() {
        return new PaginationInterceptor();
    }
}

第二个：
DataSource配置和第一个一样，调整下@MapperScan(basePackages = “com..****...dao.mapper.data1", sqlSessionTemplateRef = “slaveSqlSessionTemplate”)中basePackages="com.*****..*****.**.dao.mapper.data2" 为数据源二的mapper路径， 调整xml路径为：bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mapper/data2/.xml”));

重要：
代码中
{MybatisConfiguration config = new MybatisConfiguration();
// 开启javaBean 成员变量名映射为映射到数据库列名的时候，驼峰命名法到下划线分割命名法则的自动转换功能（）
config.setMapUnderscoreToCamelCase(true);
config.setCacheEnabled(false);
bean.setConfiguration(config);}
**极其重要！！！！！！！！！！！！**不加该配置 ，牵扯到驼峰命名的table信息都会初始化失败，报错MybatisPlusException: can not find lambda cache；网上说加：TableInfoHelper.initTableInfo(new MapperBuilderAssistant(new MybatisConfiguration(), “”), XxxxDO.class); 个人认为牵扯到很多表实体类的时候很麻烦，而且加了该处理之后，使用QueryWrapper/LambdaQueryWrapper的原生方法（selectList、selectById、update等） 时会报错“Invalid bound statement (not found)的异常”，加上该配置就OK了
最后，对应要连不同数据源的mapper和xml放在对应的数据源扫描路径下就可以了。
增加对mybatis自带分页的支持（已被坑）
config.addInterceptor(new PaginationInterceptor());
@Bean
public PaginationInterceptor paginationInterceptor() {
return new PaginationInterceptor();
}

第二种方式：

pom文件：

 		<dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>dynamic-datasource-spring-boot-starter</artifactId>
            <version>3.2.1</version>
        </dependency>

然后数据库配置：

datasource:
    dynamic:
      primary: data1
      datasource:
        data1:
           driver-class-name: com.mysql.jdbc.Driver
           type: com.zaxxer.hikari.HikariDataSource
           url: #########
           username: #########
           password: ################
           hikari:
            pool-name: Hikari
            auto-commit: false
            maximum-pool-size: 20
        data2:
           driver-class-name: com.mysql.jdbc.Driver
           type: com.zaxxer.hikari.HikariDataSource
           url: #########
           username: #########
           password: ################
           hikari:
            pool-name: Hikari
            auto-commit: false
            maximum-pool-size: 20

默认的主数据库是data1，在使用data2时只需要在mapper类加上@DS(“data2”)注解即可，比第一种方式更加简洁，且不用单独处理mybatis自带的一些配置，但是第一种方式配置更加自由。