There is no getter for property named 'str' in 'class java.lang.String'

mybatis开发时报错：

org.apache.ibatis.reflection.ReflectionException: There is no getter for property named 'str' in 'class java.lang.String'

问题出在判断这行

        <if test="str != null">
            WHERE phone_md5 = #{str}
        </if>

应该String类型变量用_parameter替换

        <if test="_parameter != null">
            WHERE phone_md5 = #{str}
        </if>