MyBatis之User.xml

<?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="com.njupt.pojo.User">


<select id="selectUserById" parameterType="string" resultType="com.njupt.pojo.User">

 select id ,name username , address  from user where id = #{id}

</select>


<select id="selectAllUsers" resultType="com.njupt.pojo.User">

 select id ,name , address  from user

</select>


<insert id="insertUser" parameterType="com.njupt.pojo.User">

 insert into user(id ,name , address) values(#{id},#{username},#{address})

</insert>


<select id="selectUserByIdForMap" parameterType="string" resultType="hashmap">

 select id ,name ,address from user where id = #{id}

</select>


<insert id="insertUserForMap" parameterType="hashmap">

  insert into user(id,name,address) values(#{id},#{username1},#{address});

</insert>


<delete id="deleteUserById" parameterType="string">

  delete from user where id = #{id}

</delete>


<update id="updateUserById" parameterType="com.njupt.pojo.User">

 update user set name = #{username} ,address = #{address} where id = #{id}

</update>


<update id="updateUserByIdForMap" parameterType="hashmap">

  update user set name = #{username2},address=#{address} where id = #{id}

</update>


<select id="selectUserByCondition" parameterType="com.njupt.pojo.User" resultType="com.njupt.pojo.User">

  select id , name username ,address from user where 1 = 1

  <if test="id != null">

     and id = #{id}

  </if>

  

  <if test="username != null">

     and name = #{username}

  </if>

  

  <if test="address != null">

     and address = #{address}

  </if>

</select>


<select id="selectUserByCondition1" parameterType="com.njupt.pojo.User" resultType="com.njupt.pojo.User">

 select id ,name as username ,address from user 

 <where>

    <if test="id != null">

        id = #{id}

    </if>

    

    <if test="username != null">

       and name = #{username}

    </if>

    

    <if test="address != null">

       and address = #{address}

    </if>

      

 </where>

</select>

 </mapper>