There is no getter for property named 'userid ’ in 'class java.lang.Integer
<--当传入数据只有一个时mybatis中<if>判断会出现判断条件里不管你传什么参,只能用_parameter 代替-->
<select id="selectUserById" parameterType="java.lang.Integer" resultType="java.util.Map">
select
<include refid="Base_Column_List" />
from user
<if test="_parameter != null">
where userid = #{_parameter,jdbcType=INTEGER}
</if>
</select>