MyBatis 映射SQL的几种方式

1配置文件方式:

ex:

1.1 SQL映射文件

<mapper namespace="com.test.dao.EmployeeMapper"><select id="getEmpById" resultType="com.test.beans.Employee">select id,last_name lastName,email,gender from tb1_emplyee where id = #{id}</select></mapper>

1.2全局配置文件:

使用Mapper标签进行绑定:

<mappers><mapper resource="EmployeeMapper.xml" /></mappers>

2.注解方式:

定义一个接口:

public interface EmployeeMapperAnnotation {    @Select("select id,last_name lastName,email,gender from tb1_emplyee where id = #{id}")    public Employee getEmpById(Integer id);}

然后在全局配置文件中进行注册:

<mappers><mapper class="com.test.dao.EmployeeMapperAnnotation"></mapper></mappers>

3.批量注册

<mappers><package name="com.atguigu.mybatis.dao"/></mappers>

tips:

映射文件名必须和接口同名，并且放在与接口同一目录下,不然注册不了。