当传入数据只有一个时mybatis中<if>判断会出现There is no getter for property named 'subjectId' in 'class java.lang....

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