Dao.java与Dao.xml相互关联

Dao.java

package com.imooc.oa.dao;
import com.imooc.oa.entity.Department;
import org.springframework.stereotype.Repository;
import java.util.List;
@Repository("departmentDao")
public interface DepartmentDao {
    void insert(Department department);
    void update(Department department);
    void delete(String sn);
    Department select(String sn);
    List<Department> selectAll();
}

Dao.xml

<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.4//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.imooc.oa.dao.DepartmentDao"> /*与接口位置对应*/

    <resultMap id="department" type="Department">/*id建议接口名小写 type为接口名*/
        <id property="sn" column="sn" javaType="String"/>/*主键  property实体类属性colum数据库表字段*/
        <result property="name" column="name" javaType="String"/>
        <result property="address" column="address" javaType="String"/>
    </resultMap>


    <insert id="insert" parameterType="Department">/*id为interface的方法名*/
        insert into department values(#{sn},#{name},#{address})/*#{xxx}为实体类的属性*/
    </insert>

    <update id="update" parameterType="Department">
        update department set name=#{name},address=#{address} where sn=#{sn}
    </update>/*name=#{name}第一个name为数据库字段名 第二个为实体类属性名*/

    <delete id="delete" parameterType="String">/*parameterType传给数据库的值的类型 */
        delete from department where sn=#{sn}
    </delete>

    <select id="select" parameterType="String" resultMap="department">
        select * from department where sn=#{sn}
    </select>

    <select id="selectAll" resultMap="department">/*resultMap从数据库返回的值的类型*/
        select * from department
    </select>

</mapper>