<?xml version="1.0" encoding="gbk"?>

<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"

 "mybatis-3-mapper.dtd">  

<mapper namespace="org.phf.mapping.UserMapper">  

    <!--开启缓存-->

  <cache />

    <!--

    select 查询语句是使用 MyBatis 时最常用的元素之一。

    id（方法）是 get, parameterType(参数类型)是Integer, resultType(返回类型)是 User对象,其属性就是列名,值是列对应的值。

     -->

  <select id="find" parameterType="Integer" resultType="User">

    SELECT * FROM TB_USER WHERE ID = #{id}

  </select>

  <!--单条数据返回类型可以是HashMap,key为列名，value为值 -->

  <select id="findMap" parameterType="Integer" resultType="HashMap">

    SELECT * FROM TB_USER WHERE ID = #{id}

    </select>  

  <!-- 返回多条数据时会自动封装成List集合返回-->

  <select id="findAll" resultType="User">

    SELECT * FROM TB_USER

  </select>  

    <!-- 最多接受一个参数，所以多个参数可以封装成对象传参,可进行判断处理-->

  <select id="findWithIf" parameterType="User" resultType="User">

    SELECT * FROM TB_USER

    <where>

        <if test="name!= null">name = #{name}</if>

        <if test="age!= null">and age = #{age}</if>

    </where>

  </select>

    <!-- 多个键值对参数也可以用map传参，key对应列名-->

  <select id="findByNameAndAge" parameterType="Map" resultType="User">

    SELECT * FROM TB_USER

    <where>

        <if test="name!= null">name = #{name}</if>

        <if test="age!= null">and age = #{age}</if>

    </where>

  </select>

    <!-- 多个单值参数也可以用List传参，循环处理-->

  <select id="findWithIn" parameterType="list" resultType="User">

    SELECT * FROM TB_USER WHERE id IN

    <foreach item="item" index="index" collection="list"

      open="(" separator="," close=")">

        #{item}

    </foreach>

  </select>

    <!-- 多个单值参数也可以用List传参，循环处理-->

  <select id="findWithLike" parameterType="String" resultType="User">

    <bind name="pattern" value="'%' + _parameter + '%'" />

    SELECT * FROM tb_user

    WHERE name LIKE #{pattern}

  </select>  

</mapper>

<typeAliases>

    <typeAlias alias="User" type="com.ken.pojo.User" />

</typeAliases>