要注册这两个文件
    CS_MyBatis - 图1
    Mapper.xml文件中的namespace与mapper接口的全限定名相同
    CS_MyBatis - 图2
    1、关联-association 集合-collection

    2、所以association是用于一对一和多对一，而collection是用于一对多的关系

    3、JavaType和ofType都是用来指定对象类型的

    JavaType是用来指定pojo中属性的类型
    ofType指定的是映射到list集合属性中pojo的类型。

    mybatis当中最后只有mapper.xml和mapper 的interface 没有mapper的实现类了，直接使用接口映射操作数据库，它上层封装了service进行对mapper的使用。而service还有实现类也就是impl因为那是自己定义的

    记录一下第一次，也是唯一一次手写的xml，mapper，service

    service

    1. public interface TStationService extends IService<TStation> {
    3.     public T_StationVO getStationInfoBySID(); //得到充电站的信息，联合查询
    4.     public int addStation(TStationDTO tStation);
    5.     public List<T_StationVO> getAllShareStation();
    6.     public int getAllStationCount(String cdz);  //获得全部充电站数量
    7.     public T_StationVO getStationById(Integer ID);
    8.     public T_StationVO getStationInfoById(Integer S_ID); //根据充电站编号得到充电站具体信息
    9.     public int updateStation(TStationDTO tStationDTO);          //更新充电站信息
    10.     public int OperatorCount(String OID);       //得到一个客服修改充电站的数目
    11.     public int getStationStateCount(Integer SID,Integer state); //某电站下处于忙状态的电桩个数
    12.     }

    mapper

    1. package com.tjpu.echargeboot.mapper;
    3. import com.baomidou.mybatisplus.annotation.SqlParser;
    4. import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
    5. import com.tjpu.echargeboot.DTO.TStationDTO;
    6. import com.tjpu.echargeboot.entity.TStation;
    7. import com.baomidou.mybatisplus.core.mapper.BaseMapper;
    8. import com.tjpu.echargeboot.vo.T_StationVO;
    10. import java.util.List;
    12. /**
    13.  * <p>
    14.  * Mapper 接口
    15.  * </p>
    16.  *
    17.  * @author zhizekai
    18.  * @since 2020-10-31
    19.  */
    20. public interface TStationMapper extends BaseMapper<TStation> {
    22.     public int addStation(TStationDTO tStation);       //添加新的充电站
    24.     //    public List<T_Station> AllStation(Page page, String orderBy, String SC, String cdz);          //得到所有充电站的列表
    25. //    public List<T_Station> AllStation(Page page);          //得到所有充电站的列表
    26. //    public List<T_Station> AllStation(Page page,String address);          //得到所有充电站的列表
    27. //    public List<T_Station> AllStation();  //无分页
    28.     public List<T_StationVO> getAllShareStation();
    30.     public int getAllStationCount(String cdz);  //获得全部充电站数量
    32.     public T_StationVO getStationById(Integer ID);
    34.     public T_StationVO getStationInfoById(Integer S_ID); //根据充电站编号得到充电站具体信息
    36.     public int updateStation(TStationDTO tStationDTO);          //更新充电站信息
    38.     public int OperatorCount(String OID);       //得到一个客服修改充电站的数目
    40.     public int getStationBusyPileCount(Integer SID); //某电站下处于忙状态的电桩个数
    42.     public int getStationReleasePileCount(Integer SID); //某电站下处于空闲状态的电桩个数
    44.     public int getStationOfflinePileCount(Integer SID); //某电站下处于离线状态的电桩个数
    45. }

    xml映射

    1. <?xml version="1.0" encoding="UTF-8"?>
    2. <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
    3. <mapper namespace="com.tjpu.echargeboot.mapper.TStationMapper">
    6.     <!--增加一条充电站信息-->
    7.     <insert id="addStation" parameterType="com.tjpu.echargeboot.DTO.TStationDTO">
    8.         INSERT INTO t_station (S_Name,
    9.                                S_Longitude,
    10.                                S_Latitude,
    11.                                S_Address,
    12.                                S_Date,
    13.                                O_ID,
    14.                                C_ID,
    15.                                S_FR,
    16.                                S_RepairTel,
    17.                                S_CompanyTel,
    18.                                S_ProDetail)
    19.         VALUES (#{S_Name}, #{S_Longitude}, #{S_Latitude}, #{S_Address}, #{S_Date}, #{O_ID}, #{C_ID}, #{S_FR},
    20.                 #{S_RepairTel}, #{S_CompanyTel}, #{S_ProDetail})
    21.     </insert>
    24.     <!--按照id查询充电站所有信息-->
    25.     <!--查询所有充电站信息-->
    26.     <resultMap id="TStationVOMap" type="com.tjpu.echargeboot.vo.T_StationVO">
    28.         <id column="S_ID" jdbcType="INTEGER" property="S_ID"/>
    29.         <result column="S_Name" jdbcType="VARCHAR" property="S_Name"/>
    30.         <result column="S_Longitude" jdbcType="DECIMAL" property="S_Longitude"/>
    31.         <result column="S_Latitude" jdbcType="DECIMAL" property="S_Latitude"/>
    32.         <result column="S_Address" jdbcType="VARCHAR" property="S_Address"/>
    33.         <result column="S_Memo" jdbcType="VARCHAR" property="S_Memo"/>
    34.         <result column="S_ServiceType" jdbcType="INTEGER" property="S_ServiceType"/>
    35.         <result column="S_ServicePrice" jdbcType="REAL" property="S_ServicePrice"/>
    36.         <result column="S_Date" jdbcType="TIMESTAMP" property="S_Date"/>
    37.         <result column="S_RepairTel" jdbcType="VARCHAR" property="S_RepairTel"/>
    38.         <result column="S_CompanyTel" jdbcType="VARCHAR" property="S_CompanyTel"/>
    39.         <result column="S_ProDetail" jdbcType="VARCHAR" property="S_ProDetail"/>
    40.         <result column="S_Num" jdbcType="VARCHAR" property="S_Num"/>
    41.         <association property="t_feeRateVO" javaType="com.tjpu.echargeboot.vo.T_FeeRateVO">
    42.             <id column="FR_ID" property="FR_ID"/>
    43.             <result column="FR_Name" property="FR_Name"/>
    44.             <result column="FR_1" property="FR_1"/>
    45.             <result column="FR_SPrice" property="FR_SPrice"/>
    46.         </association>
    47.         <association property="t_companyVO" javaType="com.tjpu.echargeboot.vo.T_CompanyVO">
    48.             <id column="C_ID" property="C_ID"/>
    49.             <result column="C_Name" property="C_Name"/>
    50.         </association>
    51.         <association property="t_operatorVO" javaType="com.tjpu.echargeboot.vo.T_OperatorVO">
    52.             <id column="O_ID" property="O_ID"/>
    53.         </association>
    54.     </resultMap>
    55.     <select id="getStationInfoById" parameterType="int" resultMap="TStationVOMap">
    56.         SELECT A.*,
    57.                B.C_Name,
    58.                C.*
    59.         FROM t_station A,
    60.              t_company B,
    61.              t_feerate C
    62.         WHERE A.C_ID = B.C_ID
    63.           AND A.S_FR = C.FR_ID
    64.           AND A.S_ID = #{id}
    65.     </select>
    68.     <!--查询分享充电站-->
    69.     <resultMap id="AllShareStationMap" type="com.tjpu.echargeboot.vo.T_StationVO">
    70.         <id column="S_ID" jdbcType="INTEGER" property="S_ID"/>
    71.         <result column="S_Name" jdbcType="VARCHAR" property="S_Name"/>
    72.         <result column="S_Num" jdbcType="VARCHAR" property="S_Num"/>
    73.         <result column="S_Longitude" jdbcType="DECIMAL" property="S_Longitude"/>
    74.         <result column="S_Latitude" jdbcType="DECIMAL" property="S_Latitude"/>
    75.         <result column="S_Address" jdbcType="VARCHAR" property="S_Address"/>
    76.         <result column="S_Memo" jdbcType="VARCHAR" property="S_Memo"/>
    77.         <result column="S_Date" jdbcType="TIMESTAMP" property="S_Date"/>
    78.         <association property="t_operatorVO" javaType="com.tjpu.echargeboot.vo.T_OperatorVO">
    79.             <result column="O_ID" jdbcType="VARCHAR" property="O_ID"/>
    80.         </association>
    81.         <association property="t_companyVO" javaType="com.tjpu.echargeboot.vo.T_CompanyVO">
    82.             <result column="C_ID" jdbcType="INTEGER" property="C_ID"/>
    83.             <result column="C_Name" jdbcType="VARCHAR" property="C_Name"/>
    84.         </association>
    85.     </resultMap>
    86.     <select id="getAllShareStation" resultMap="AllShareStationMap">
    87.         SELECT A.*,
    88.                B.C_Name
    89.         FROM t_station A,
    90.              t_company B
    91.         where A.S_Type = 2
    92.           And A.C_ID = B.C_ID
    93.     </select>
    96.     <!--查询充电站数量-->
    97.     <select id="getAllStationCount" parameterType="string" resultType="int" >
    98.         select count(*) AS cn from t_station
    99.         <where>
    100.             <if test="cdz!=''">
    101.                 and t_station.S_Name=#{cdz}
    102.             </if>
    103.         </where>
    104.     </select>
    105.     <update id="updateStation" parameterType="com.tjpu.echargeboot.DTO.TStationDTO">
    106.         update t_station set S_Name=#{S_Name},S_Longitude=#{S_Longitude},
    107.                              S_Latitude=#{S_Latitude},S_Address=#{S_Address},
    108.                              O_ID=#{O_ID},C_ID=#{C_ID},S_FR=#{S_FR},
    109.                              S_RepairTel=#{S_RepairTel},S_CompanyTel=#{S_CompanyTel},
    110.                              S_ProDetail=#{S_ProDetail} where S_ID=#{S_ID}
    111.     </update>
    114.     <!--某电站下处于忙状态的电桩个数-->
    115.     <select id="getStationBusyPileCount" parameterType="int" resultType="int">
    116.         SELECT
    117.             count( 1 ) AS cn
    118.         FROM
    119.             t_station A,
    120.             t_chgpile B
    121.         WHERE
    122.             A.S_ID = #{S_ID}
    123.           AND A.S_ID = B.S_ID
    124.           AND (
    125.                 B.CP_State = 2
    126.                 OR B.CP_State = 3)
    127.     </select>
    130.     <!--某电站下处于空闲状态的电桩个数-->
    131.     <select id="getStationReleasePileCount" parameterType="int" resultType="int">
    132.         SELECT
    133.             count( 1 ) AS cn
    134.         FROM
    135.             t_station A,
    136.             t_chgpile B
    137.         WHERE
    138.             A.S_ID = #{S_ID}
    139.           AND A.S_ID = B.S_ID
    140.           AND B.CP_State =1
    141.     </select>
    144.     <!--某电站下处于空闲状态的电桩个数-->
    145.     <select id="getStationReleasePileCount" parameterType="int" resultType="int">
    146.         SELECT
    147.             count( 1 ) AS cn
    148.         FROM
    149.             t_station A,
    150.             t_chgpile B
    151.         WHERE
    152.             A.S_ID = #{S_ID}
    153.           AND A.S_ID = B.S_ID
    154.           AND B.CP_State =1
    155.     </select>
    158.     <!--某电站下处于离线状态的电桩个数-->
    159.     <select id="getStationOfflinePileCount" parameterType="int" resultType="int">
    160.         SELECT
    161.             count( 1 ) AS cn
    162.         FROM
    163.             t_station A,
    164.             t_chgpile B
    165.         WHERE
    166.             A.S_ID =#{S_ID}
    167.           AND A.S_ID = B.S_ID
    168.           AND (
    169.                 B.CP_State = 4
    170.                 OR B.CP_State = 5)
    171.     </select>
    173. </mapper>