title: how could I prevent Mybatis from overwriting the already generated mapper files in DAO?
body: <p>Since the requirements are changing,I need to update the DAO's mapper files from time to time using Mybatis. And here is the problem that I got: we've already generated a set of mapper xml files and additionally,we defined our own specific elements in the mapper file.</p>
  
  <pre><code>&lt;select id="selectTop20PlayerOfClassicCard" resultMap="CollectionRankingMap"&gt;
      SELECT playerid,count(cardid) from re_player_card where type in (0,1) GROUP
      BY playerid ORDER BY COUNT(*) DESC limit 20;
  &lt;/select&gt;
  
  &lt;select id="selectTop20PlayerOfSpecialCard" resultMap="CollectionRankingMap"&gt;
      SELECT playerid,count(cardid) from re_player_card where type=2 GROUP BY
      playerid ORDER BY COUNT(*) DESC limit 20;
  &lt;/select&gt;
  
  &lt;resultMap id="CollectionRankingMap" type="dymaic.RePlayerCardRanking"&gt;
      &lt;!-- manually generated --&gt;
      &lt;result column="playerid" jdbcType="INTEGER" property="playerid" /&gt;
      &lt;result column="count(cardid)" jdbcType="INTEGER" property="count" /&gt;
  &lt;/resultMap&gt;
  
  &lt;select id="getCardIdByPlayerId" parameterType="int" resultType="int"&gt;
      select
      re_player_card.cardid
      from re_player_card
      where playerid = #{playerid}
  &lt;/select&gt;
  </code></pre>
  
  <p>The 3 select statements and the resultmap are defined by ourselves. Now I'm going to regenerate the mapper files again.But I don't want these statement blocks to be overwriten. I need to keep them in the mapper file while changing the rest with Mybatis. </p>
  
  <p>I'm using the Mybatis generator eclipse plugin. So is there any way to make it? I'd appreciate for you guys' help.</p>