当传入数据只有一个值的时候mybatis会报错

用"_parameter"代替当前参数

正确：

<select id="selectSubjectByPId"  parameterType="java.lang.Integer" resultType="java.util.Map">        select subjectId,subjectName         from ts_subject         where subjectParentId= 0         <if test="_parameter != null">            and subjectId = #{_parameter,jdbcType=INTEGER}        </if></select>

错误：

<select id="selectSubjectByPId"  parameterType="java.lang.Integer" resultType="java.util.Map">        select subjectId,subjectName         from ts_subject         where subjectParentId= 0         <if test="subjectId != null">            and subjectId = #{subjectId,jdbcType=INTEGER}        </if></select>

这时候就会出现异常.

There is no getter for property named 'subjectId' in 'class java.lang.Intege