mybatis简单案例源码详细【注释全面】——Dao层映射文件（UserMapper.xml）【重要】

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="org.dao.UserMapper">
  
  <!-- user的resultMap,当数据库字段信息和对象的属性不一样时，需要通过resultMap来映射 -->
  <!--association,property,对应的是实体类对象的名称；resultMap对应的是另一个表的映射  -->
  <resultMap type="Users" id="userList">
    <result property="id" column="id"/>
    <result property="userCode" column="userCode"/>
    <result property="userName" column="userName"/>
    <result property="userPassword" column="userPassword"/>
    <result property="gender" column="gender"/>
    <result property="birthday" column="birthday"/>
    <result property="phone" column="phone"/>
    <result property="address" column="address"/>
    <result property="userrole" column="userrole"/>
    <result property="createBy" column="createBy"/>
    <result property="creationDate" column="creationDate"/>
    <result property="modifyBy" column="modifyBy"/>
    <result property="modifyDate" column="modifyDate"/>
    <association property="role" resultMap="roleList"/>
  </resultMap>
  <!-- Role的resultMap -->
  <resultMap type="Role" id="roleList">
    <result property="id" column="id"/>
    <result property="roleCode" column="roleCode"/>
    <result property="roleName" column="roleName"/>
    <result property="createdBy" column="createdBy"/>
    <result property="creationDate" column="creationDate"/>
    <result property="modifyBy" column="modifyBy"/>
    <result property="modifyDate" column="modifyDate"/>
    
  </resultMap>
  <!-- 查询用户表的记录数 -->
  <select id="count" resultType="int">
    select count(*) from user
  </select>
  
  <!-- 查询所有的用户信息 -->
  <select id="getUserList" resultType="Users">
    select * from user
  </select>
  
  <!-- 根据用户名进行模糊查询 -->
  <select id="getUsersByName" resultMap="userList" parameterType="string">
    select * from user where userName like concat ('%',#{userName},'%')
  </select>
  
  <!-- 查询用户列表 -->
  <select id="getUserListByUser" resultMap="userList" parameterType="Users">
    select * from user where userName like concat('%',#{userName},'%') and userRole = #{userrole}
  </select>
  
  <!-- 查询用户列表，参数是Map集合 -->
  <select id="getUsersListByMap" resultMap="userList" parameterType="Map">
    select * from user where userName like concat ('%',#{userName},'%') and userRole = #{userrole}
  </select>
  
  <!-- 查询用户列表，连接查询-->
  <select id="getUserListAndRole" resultMap="userList" parameterType="Users">
    
  select * from user u join role r on u.userRole = r.id  
    where u.userName like concat ('%',#{userName},'%') and u.userrole = #{userrole}
  </select>
  
  <!-- 增加用户,字段名必须都写上 -->
  <insert id="saveUser" parameterType="Users">
    insert into user (userCode,userName,userPassword,gender,birthday,phone,
                address,userRole,createdBy,creationDate,modifyBy,modifyDate) 
    values(#{userCode},#{userName},#{userPassword},#{gender},#{birthday},#{phone},#{address},#{userrole},#{createBy},#{creationDate},#{modifyBy},#{modifyDate})
  </insert>
  
  <!-- 根据id修改信息 -->
  <update id="updateUser" parameterType="Users">
    update user set userCode=#{userCode},userName=#{userName},userPassword=#{userPassword},gender=#{gender},
            birthday=#{birthday},phone=#{phone},address=#{address},userRole=#{userrole},createdBy=#{createBy},
            creationDate=#{creationDate},modifyBy=#{modifyBy},modifyDate=#{modifyDate}
            where id=#{id}
  </update>
  
  <!-- 根据编号进行删除数据 -->
  <delete id="delUser" parameterType="int">
    delete from user where id=#{id}
  </delete>
  
  <!-- 根据id查询用户列表 -->
  <select id="getUsersById" parameterType="int" resultMap="userList">
    select * from user where id = #{id}
  </select>
  
  <!-- 根据角色id查询用户列表 -->
  <select id="getUsersByRoleId" parameterType="int" resultMap="userList">
    select * from user u,role r where u.userrole = #{userrole} and r.id = u.userrole
  </select>
  
  <!-- 根据用户名和角色编号查询用户信息 -->
  <select id="getUsersListByUserNameAndRole_if" resultMap="userList">
    select * from user u, role r where u.userrole=r.id
    <if test="userrole!=null">
      and userrole = #{userrole}
    </if>
    <if test="userName!=null">
      and userName like concat('%',#{userName},'%')
    </if>
  </select>
  
  <!-- 动态根据用户名和角色id查询用户列表，where and|or -->
  <select id="getUsersListByUserNameAndRole_ifAndwhere" resultMap="userList">
    select * from user 
    <where>
      <if test="userrole!=null and userrole!=''">
        and userrole = #{userrole}
      </if>
      <if test="userName!=null and userName!=''">
        and userName like concat('%',#{userName},'%')
      </if>
    </where>
  </select>
  
  <!-- 动态修改用户信息表if+set -->
  <update id="updateUser_ifAndSet" parameterType="Users">
    update user
    <set>
      <if test="userCode!=null">userCode=#{userCode},</if>
      <if test="userName!=null">userName=#{userName},</if>
      <if test="userPassword!=null">userPassword=#{userPassword},</if>
      <if test="gender!=null">gender=#{gender},</if>
      <if test="birthday!=null">birthday=#{birthday},</if>
      <if test="phone!=null">phone=#{phone},</if>
      <if test="address!=null">address=#{address},</if>
      <if test="userrole!=null">userrole=#{userrole},</if>
      <if test="createBy!=null">createdBy=#{createBy},</if>
      <if test="creationDate!=null">creationDate=#{creationDate},</if>
      <if test="modifyBy!=null">modifyBy=#{modifyBy},</if>
      <if test="modifyDate!=null">modifyDate=#{modifyDate},</if>
    </set>
      where id=#{id}
  </update>
  
  
  <!-- 动态根据用户名和角色id查询用户列表，使用trim进行查询用户信息，where and|or -->
  <!-- prefix:前缀，通过自动识别是否有返回值，在trim包含的内容上加上前缀 -->
  <!-- suffix:后缀，在trim包含的内容的上加上后缀 -->
  <!-- prefixOverrides:对于trim包含的内容的首部进行指定内容 -->
  <!-- suffixOverrides：地狱与trim包含的内容的首尾部进行指定内容的忽略 -->
  <select id="getUsersListByUserNameAndRole_ifAndwhere_trim" resultMap="userList">
    select * from user 
    <trim prefix="where" prefixOverrides="and | or">
      <if test="userrole!=null and userrole!=''">
        and userrole = #{userrole}
      </if>
      <if test="userName!=null and userName!=''">
        and userName like concat('%',#{userName},'%')
      </if>
    </trim>
  </select>
  
  <!-- 动态修改用户信息表if+trim -->
  <update id="updateUser_ifAndTrim" parameterType="Users">
    update user
    <trim prefix="set" suffixOverrides="," suffix="where id=#{id}">
      <if test="userCode!=null">userCode=#{userCode},</if>
      <if test="userName!=null">userName=#{userName},</if>
      <if test="userPassword!=null">userPassword=#{userPassword},</if>
      <if test="gender!=null">gender=#{gender},</if>
      <if test="birthday!=null">birthday=#{birthday},</if>
      <if test="phone!=null">phone=#{phone},</if>
      <if test="address!=null">address=#{address},</if>
      <if test="userrole!=null">userrole=#{userrole},</if>
      <if test="createBy!=null">createdBy=#{createBy},</if>
      <if test="creationDate!=null">creationDate=#{creationDate},</if>
      <if test="modifyBy!=null">modifyBy=#{modifyBy},</if>
      <if test="modifyDate!=null">modifyDate=#{modifyDate},</if>
    </trim>
  </update>
  
  <!-- 根据用户角色列表，获取该角色刘表下用户列表信息foreach_array -->
  <!-- item：循环体中的具体对象。支持属性的点路径访问，如item.age,item.info.details。 具体说明：在list和数组中是其中的对象，在map中是value。该参数为必选。 -->
  <!-- collection：要做foreach的对象，作为入参时，List<?>对象默认用list代替作为键，数组对象有array代替作为键，Map对象没有默认的键。
          当然在作为入参时可以使用@Param("keyName")来设置键，设置keyName后，list,array将会失效。 除了入参这种情况外，还有一种作为参数对象的某个字段的时候。举个例子：
          如果User有属性List ids。入参是User对象，那么这个collection = "ids"
          如果User有属性Ids ids;其中Ids是个对象，Ids有个属性List id;入参是User对象，那么collection = "ids.id"
          上面只是举例，具体collection等于什么，就看你想对那个元素做循环。
          该参数为必选。 -->
  <!-- separator：元素之间的分隔符，例如在in()的时候，separator=","会自动在元素中间用“,“隔开，避免手动输入逗号导致sql错误，如in(1,2,)这样。该参数可选。 -->
  <!-- open：foreach代码的开始符号，一般是(和close=")"合用。常用在in(),values()时。该参数可选。 -->
  <!-- close：foreach代码的关闭符号，一般是)和open="("合用。常用在in(),values()时。该参数可选。 -->
  <!-- index：在list和数组中,index是元素的序号，在map中，index是元素的key，该参数可选。 -->
  <select id="getUsersByRoleId_foreach_array" resultMap="userList">
    select * from user where userrole in 
      <foreach collection="array" item="roleids" open="(" separator="," close=")">
        #{roleids}
      </foreach>
  </select>
  
  <!-- 根据用户角色列表，获取该角色刘表下用户列表信息foreach_list -->
  <select id="getUsersByRoleId_foreach_list" resultMap="userList">
    select * from user where userrole in 
    <foreach collection="list" item="roleids" open="(" separator="," close=")">
      #{roleids}
    </foreach>
  </select>
  
  <!-- 根据用户角色列表和性别（多参数），获取该角色刘表下用户列表信息foreach_map -->
  <select id="getUsersByRoleId_foreach_many_map" resultMap="userList">
    select * from user where gender = #{gender} and  userrole in 
    <foreach collection="roleids" item="roleMap" open="(" separator="," close=")">
      #{roleMap}
    </foreach>
  </select>
  
  <!-- 根据用户角色列表（单参数），获取该角色刘表下用户列表信息foreach_map -->
  <select id="getUsersByRoleId_foreach_one_map" resultMap="userList">
    select * from user where   userrole in 
    <foreach collection="rKey" item="roleMap" open="(" separator="," close=")">
      #{roleMap}
    </foreach>
  </select>
  
  <!-- 查询用户列表，使用choose -->
  <select id="getUsersList_choose" resultMap="userList">
    select * from user where 1=1
      <choose>
        <when test="userName!=null and userName!=''">
          and userName  like concat('%',#{userName},'%')
        </when>
        <when test="userrole!=null">
          and userrole =#{userrole}
        </when>
        <when test="userCode!=null and userCode!=''">
          and userCode =#{userCode}
        </when>
        <otherwise>
          and YEAR(creationDate) = YEAR(#{creationDate})
        </otherwise>
      </choose>
  </select>
  
  <!-- 分页显示用户信息 -->
  <select id="getUserList_page" resultMap="userList">
    select * from user limit #{from},#{pageSize}
  </select>
</mapper>