Mybatis-plus之空值无法插入问题及解决

mybatis：
  configuration:
    mapUnderscoreToCamelCase: true
    jdbc-type-for-null: 'null'
  mapper-locations: classpath*:mapper/*.xml

@Configuration
@MapperScan(basePackages = {"com.XXXX.mapper"}, sqlSessionFactoryRef = "XXXXXX")
public class DbYYConfig {

    @Autowired
    @Qualifier("XXXX")
    private DataSource dataSourceDb2;

    @Bean
    public SqlSessionFactory sqlSessionFactoryDb2() throws Exception {
        SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
        factoryBean.setDataSource(dataSourceDb2);
        factoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mapper/*.xml"));
        org.apache.ibatis.session.Configuration configuration = new org.apache.ibatis.session.Configuration();
        configuration.setMapUnderscoreToCamelCase(true);
        configuration.setJdbcTypeForNull(JdbcType.NULL);
        factoryBean.setConfiguration(configuration);
        return factoryBean.getObject();
    }

    @Bean
    public SqlSessionTemplate sqlSessionTemplateDb2() throws Exception {
        return new SqlSessionTemplate(sqlSessionFactoryDb2());
    }

}