在mapper.xml中设置如下
<resultMap type="com.yd.www.entity.Filelist" id="FilelistMap">
  <id column="id" property="id"/>
  <id column="file_name" property="fileName" />
  <id column="file_type" property="fileType" />
  <id column="file_url" property="fileUrl" />
  <id column="file_creatime" property="fileCreatime" />
  <id column="uploader_id" property="uploaderId" />
  <id column="uploader_name" property="uploaderName" />
</resultMap>