是mybatis 中返回类型一定用到的，但不会同时出现。mybatis返回类型肯定是map结构，然后根据返回类型是map还是对象类型，再转换。

在给对象设置属性的时候，两个方法肯定会调用。

private Object getRowValue(ResultSetWrapper rsw, ResultMap resultMap) throws SQLException {    final ResultLoaderMap lazyLoader = new ResultLoaderMap();    Object resultObject = createResultObject(rsw, resultMap, lazyLoader, null);    if (resultObject != null && !typeHandlerRegistry.hasTypeHandler(resultMap.getType())) {      final MetaObject metaObject = configuration.newMetaObject(resultObject);      boolean foundValues = resultMap.getConstructorResultMappings().size() > 0;      if (shouldApplyAutomaticMappings(resultMap, !AutoMappingBehavior.NONE.equals(configuration.getAutoMappingBehavior()))) {                foundValues = applyAutomaticMappings(rsw, resultMap, metaObject, null) || foundValues;      }      foundValues = applyPropertyMappings(rsw, resultMap, metaObject, lazyLoader, null) || foundValues;      foundValues = lazyLoader.size() > 0 || foundValues;      resultObject = foundValues ? resultObject : null;      return resultObject;    }    return resultObject;  }

private boolean applyAutomaticMappings(ResultSetWrapper rsw, ResultMap resultMap, MetaObject metaObject, String columnPrefix) throws SQLException {    final List
    
      unmappedColumnNames = rsw.getUnmappedColumnNames(resultMap, columnPrefix);    
      //unmappedColumnNames是配置文件中未配的resultMap中的属性，下面是自动映射规则，去设值    boolean foundValues = false;    for (String columnName : unmappedColumnNames) {      String propertyName = columnName;      if (columnPrefix != null && columnPrefix.length() > 0) {        // When columnPrefix is specified,        // ignore columns without the prefix.        if (columnName.toUpperCase(Locale.ENGLISH).startsWith(columnPrefix)) {          propertyName = columnName.substring(columnPrefix.length());        } else {          continue;        }      }   
       //这个自动映射属性的规则，很普通，根据映射出的属性，利用反射查找该对象，是否存在此属性，以便设值     final String property = metaObject.findProperty(propertyName, configuration.isMapUnderscoreToCamelCase());      if (property != null && metaObject.hasSetter(property)) {        final Class
      propertyType = metaObject.getSetterType(property);        if (typeHandlerRegistry.hasTypeHandler(propertyType)) {          final TypeHandler
      typeHandler = rsw.getTypeHandler(propertyType, columnName);          final Object value = typeHandler.getResult(rsw.getResultSet(), columnName);          if (value != null || configuration.isCallSettersOnNulls()) { // issue #377, call setter on nulls            if (value != null || !propertyType.isPrimitive()) {              metaObject.setValue(property, value);            }            foundValues = true;          }        }      }    }    return foundValues;  }
    

private boolean applyPropertyMappings(ResultSetWrapper rsw, ResultMap resultMap, MetaObject metaObject, ResultLoaderMap lazyLoader, String columnPrefix)      throws SQLException {    final List
    
      mappedColumnNames = rsw.getMappedColumnNames(resultMap, columnPrefix);
     //mappedColumnNames 是配置文件中配置resultMap中对应的映射，如果不配，此方法体就不会执行，走上面那该自动映射规则去映射属性（非常智能，但这个智能属性对应，不怎么特殊，也没提供自动映射拓展点     boolean foundValues = false;    final List
     
       propertyMappings = resultMap.getPropertyResultMappings();    for (ResultMapping propertyMapping : propertyMappings) {      final String column = prependPrefix(propertyMapping.getColumn(), columnPrefix);      if (propertyMapping.isCompositeResult()           || (column != null && mappedColumnNames.contains(column.toUpperCase(Locale.ENGLISH)))           || propertyMapping.getResultSet() != null) {        Object value = getPropertyMappingValue(rsw.getResultSet(), metaObject, propertyMapping, lazyLoader, columnPrefix);        final String property = propertyMapping.getProperty(); // issue #541 make property optional        if (value != NO_VALUE && property != null && (value != null || configuration.isCallSettersOnNulls())) { // issue #377, call setter on nulls          if (value != null || !metaObject.getSetterType(property).isPrimitive()) {            metaObject.setValue(property, value);          }          foundValues = true;        }      }    }    return foundValues;  }