特别注意，此种方法和starter不兼容，我用了两个方式混蛋，发现跑不起来！

spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/mybatis?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=UTC
    username: root
    password: 123456
    dbcp:
      max-active: 20
      max-idle: 20
      max-wait: 60000
      min-idle: 1
      initial-size: 0

package org.sselab.config;


import org.apache.commons.dbcp.BasicDataSource;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.context.properties.ConfigurationProperties;
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 org.springframework.transaction.annotation.EnableTransactionManagement;
import org.springframework.transaction.support.ResourceTransactionManager;

import javax.sql.DataSource;

@Configuration
@EnableTransactionManagement
@MapperScan("org.sselab.mapper")
public class MybatisConfig {

    @Bean
    @ConfigurationProperties(prefix = "spring.datasource")
    public DataSource dataSource() throws Exception {
        return new BasicDataSource();
    }

    @Bean
    public SqlSessionFactory sqlSessionFactory() throws Exception {
        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        sqlSessionFactoryBean.setDataSource(dataSource());
        PathMatchingResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
        sqlSessionFactoryBean.setMapperLocations(resolver.getResources("classpath:/mapper/*.xml"));
        return sqlSessionFactoryBean.getObject();
    }

    @Bean
    public PlatformTransactionManager transactionManager() throws Exception {
        return new DataSourceTransactionManager(dataSource());
    }
}

boot之mybatis