<!-- 利用hashmap传递参数数据查询用户 --><select id ="selectUserById4Map" parameterType="string" resultType="hashmap" >select<include refid ="allColumns" />from user where id = #{id}</select><!-- 利用hashmap传递参数数据插入用户信息 --><select id ="insertUser4Map" parameterType="hashmap" >insert into user(id,name,age,address) values(#{id},#{name},#{age},#{address})</select><!-- 模糊查询 --><select id ="selectUserByCondition3" parameterType="com.judy.mybatis.domain.User" resultType="com.judy.mybatis.domain.User" >select * from user where 1 = 1<if test ="id!=null" >and id = #{id}</if><if test ="name!=null" >and name like '%${name}%'</if><if test ="age!=null" >and age = #{age}</if><if test ="address!=null" >and address = #{address}</if></select>

 <!-- 利用动态sql语句更新user数据 --><insert id ="updateUserByCondition" parameterType="com.judy.mybatis.domain.User" >update user<set><if test ="name!=null" >name = #{name}</if><if test ="age!=null" >age = #{age}</if><if test ="address!=null" >address = #{address}</if></set>where id=#{id}</insert><!-- 动态seql语句查询用户 --><select id ="selectUserByCondition" parameterType="com.judy.mybatis.domain.User" resultType="com.judy.mybatis.domain.User" >select * from user where 1 = 1<if test ="id!=null" >and id = #{id}</if><if test ="name!=null" >and name = #{name}</if><if test ="age!=null" >and age = #{age}</if><if test ="address!=null" >and address = #{address}</if></select><!-- 动态seql语句查询用户方式2 --><!-- 这种方式会自动根据是否有id，如果有没有id，那么第一个条件将不加and --><select id ="selectUserByCondition2" parameterType="com.judy.mybatis.domain.User" resultType="com.judy.mybatis.domain.User" >select * from user<where><if test ="id!=null" >id = #{id}</if><if test ="name!=null" >and name = #{name}</if><if test ="age!=null" >and age = #{age}</if><if test ="address!=null" >and address = #{address}</if></where></select>

  <!-- 当字段很多的时候，可以通过下面这种方式抽取字段 --><sql id ="allColumns" >id,name,age,address</sql><!-- 如果在sqlMapConfig.xml中配置了别名，那么这里的resultType就可以直接写User --><select id ="selectUserById" parameterType="string" resultMap="userMap" >select<include refid ="allColumns" />from user where id = #{id}</select>