org.apache.ibatis.ognl.OgnlException: source is null for getProperty(null, “xxxx“)] with root cause

    <select id="getTotal" resultType="java.lang.Long">
        select count(*) from employee e
        <where>
        <!--<if test="emp !=null">-->
            <if test="emp.name != null and emp.name!=''">
                and e.name like concat('%',#{emp.name},'%')
            </if>
            <if test="emp.politicId != null">
                and e.politicId =#{emp.politicId}
            </if>
            <if test="emp.jobLevelId != null">
                and e.jobLevelId =#{emp.jobLevelId}
            </if>
            <if test="emp.posId != null">
                and e.posId =#{emp.posId}
            </if>
            <if test="emp.nationId != null">
                and e.nationId =#{emp.nationId}
            </if>
            <if test="emp.departmentId != null">
                and e.departmentId =#{emp.departmentId}
            </if>
            <if test="emp.engageForm != null">
                and e.engageForm =#{emp.engageForm}
            </if>
            <if test="beginDateScope !=null">
                and emp.beginDate between #{beginDateScope[0]} and #{beginDateScope[1]}
            </if>
        <!--</if>-->
        </where>
    </select>

Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.builder.BuilderException: Error evaluating expression 'emp.name != null and emp.name!='''. Cause: org.apache.ibatis.ognl.OgnlException: source is null for getProperty(null, "name")] with root cause

org.apache.ibatis.ognl.OgnlException: source is null for getProperty(null, "name")