如何使用 Jdbc 模板映射一对多

   List users = new ArrayList<>();
   User currentUser = null;
   while(rs.next()) {
        long id = rs.getLong("id");
        if (currentUser == null) { // initial object
            currentUser = mapUser(rs);
        } else if (currentUser.getId() != id) { // break
            users.add(currentUser);
            currentUser = mapUser(rs);
        }
        currentUser.addRole(mapRole(rs));
   }
   if (currentUser != null) { // last object
        users.add(currentUser);        
   }

    private final ResultSetExtractor> resultSetExtractor = 
        JdbcTemplateMapperFactory
            .newInstance()
            .addKeys("id") // the column name you expect the user id to be on
            .newResultSetExtractor(User.class);

   String query = 
        "SELECT u.id as id, u.username, u.id    as adverts_id, ad.text as adverts_text"
        + "FROM user u LEFT OUTER JOIN advert ad ON ad.account_id = ac.id order by id " 
 
    List results = template.query(query, resultSetExtractor);

    private final ResultSetExtractor>> resultSetExtractor = 
        JdbcTemplateMapperFactory
            .newInstance()
            .addKeys("id") // the column name you expect the user id to be on
            .newResultSetExtractor(new TypeReference>> {});

   String query = 
        "SELECT u.id as id, u.username, u.id    as adverts_id, ad.text as adverts_text"
        + "FROM user u LEFT OUTER JOIN advert ad ON ad.account_id = ac.id order by id " 
 
    List>> results = template.query(query, resultSetExtractor);