import org.apache.ibatis.executor.result.DefaultMapResultHandler; //导入依赖的package包/类
@Override
public <K, V> Map<K, V> selectMap(String statement, Object parameter, String mapKey, RowBounds rowBounds) {
  final List<? extends V> list = selectList(statement, parameter, rowBounds);
  final DefaultMapResultHandler<K, V> mapResultHandler = new DefaultMapResultHandler<K, V>(mapKey,
      configuration.getObjectFactory(), configuration.getObjectWrapperFactory(), configuration.getReflectorFactory());
  final DefaultResultContext<V> context = new DefaultResultContext<V>();
  for (V o : list) {
    context.nextResultObject(o);
    mapResultHandler.handleResult(context);
  }
  return mapResultHandler.getMappedResults();
}
 

import org.apache.ibatis.executor.result.DefaultMapResultHandler; //导入依赖的package包/类
@Override
public <K, V> Map<K, V> selectMap(String statement, Object parameter, String mapKey, RowBounds rowBounds) {
	final List<?> list = selectList(statement, parameter, rowBounds);
	final DefaultMapResultHandler<K, V> mapResultHandler = new DefaultMapResultHandler<K, V>(mapKey,
			configuration.getObjectFactory(), configuration.getObjectWrapperFactory(),
			configuration.getReflectorFactory());
	final DefaultResultContext context = new DefaultResultContext();
	for (Object o : list) {
		context.nextResultObject(o);
		mapResultHandler.handleResult(context);
	}
	Map<K, V> selectedMap = mapResultHandler.getMappedResults();
	return selectedMap;
}
 

import org.apache.ibatis.executor.result.DefaultMapResultHandler; //导入依赖的package包/类
@Override
public <K, V> Map<K, V> selectMap(String statement, Object parameter, String mapKey, RowBounds rowBounds) {
  //转而去调用selectList
  final List<?> list = selectList(statement, parameter, rowBounds);
  final DefaultMapResultHandler<K, V> mapResultHandler = new DefaultMapResultHandler<K, V>(mapKey,
      configuration.getObjectFactory(), configuration.getObjectWrapperFactory());
  final DefaultResultContext context = new DefaultResultContext();
  for (Object o : list) {
    //循环用DefaultMapResultHandler处理每条记录
    context.nextResultObject(o);
    mapResultHandler.handleResult(context);
  }
  //注意这个DefaultMapResultHandler里面存了所有已处理的记录(内部实现可能就是一个Map)，最后再返回一个Map
  return mapResultHandler.getMappedResults();
}