23 | SpringBoot整合Mybatis（注解方式）

加入依赖

<dependency>
    <groupId>org.mybatis.spring.bootgroupId>
    <artifactId>mybatis-spring-boot-starterartifactId>
    <version>2.1.3version>
dependency>

指定一个操作数据库的mapper

//指定这是一个操作数据库的mapper
@Mapper
public interface DepartmentMapper {

    @Select("select * from department where id=#{id}")
    public Department getDeptById(Integer id);

    @Delete("delete from department where id=#{id}")
    public int deleteDeptById(Integer id);

    @Options(useGeneratedKeys = true,keyProperty = "id")
    @Insert("insert into department(departmentName) values(#{departmentName})")
    public int insertDept(Department department);

    @Update("update department set departmentName=#{departmentName} where id=#{id}")
    public int updateDept(Department department);
}

但是，如果数据库的命名规则是采用驼峰命名规则，则无法操作数据库（得到的值为null），怎么办呢？？？可以进行自定义MyBatis的配置规则

自定义MyBatis的配置规则；给容器中添加一个ConfigurationCustomizer

@org.springframework.context.annotation.Configuration
public class MyBatisConfig {

    @Bean
    public ConfigurationCustomizer configurationCustomizer(){
        return new ConfigurationCustomizer(){

            @Override
            // 采用驼峰命名规则
            public void customize(Configuration configuration) {
                configuration.setMapUnderscoreToCamelCase(true);
            }
        };
    }
}

全局扫描mapper

如果觉得一个一个地在mapper接口上写@Mapper很麻烦，可以在 SpringBoot06DataMybatisApplication类上配置@MapperScan

使用MapperScan批量扫描所有的Mapper接口；
@MapperScan(value = "com.atguigu.springboot.mapper")
@SpringBootApplication
public class SpringBoot06DataMybatisApplication {

	public static void main(String[] args) {
		SpringApplication.run(SpringBoot06DataMybatisApplication.class, args);
	}
}