根据您的问题，我假设您有三个表。客户，品牌，订单。如果要将“客户”的“品牌和订单”属性获取到客户对象（“品牌”和“订单”之间没有关系），我建议使用UNIOn查询。像这样：
TBL_CUSTOMER------------CUSTOMER_IDCUSTOMER_ACCOUNT_NOCUSTOMER_NAMETBL_CUSTOMER_BRANDS-------------------CUSTOMER_BRAND_ID - UKBRAND_NAMECUSTOMER_ID - FKTBL_ORDERS-------------------ORDER_ID - UKCUSTOMER_ID - FK
查询：
SELECt CUS.*, BRANDS.CUSTOMER_BRAND_ID COL_A, BRANDS.BRAND_NAME COL_B, 1 IS_BRAND FROM TBL_CUSTOMER CUS JOIN TBL_CUSTOMER_BRANDS BRANDS ON (CUS.CUSTOMER_ID = BRANDS.CUSTOMER_ID)UNIOn ALLSELECt CUS.*, ORDERS.ORDER_ID, '', 0 IS_BRAND FROM TBL_CUSTOMER CUS JOIN TBL_ORDERS ORDERS ON (CUS.CUSTOMER_ID = ORDERS.CUSTOMER_ID)
您的ResultSetExtractor将变为：
private class MyObjectExtractor implements ResultSetExtractor{ public Object extractData(ResultSet rs) throws SQLException, DataAccessException { Map<Long, Customer> map = new HashMap<Long, Customer>(); while (rs.next()) { Long id = rs.getLong("CUSTOMER_ID"); Customer customer = map.get(id); if(customer == null){ customer = new Customer(); customer.setId(id); customer.setName(rs.getString("CUSTOMER_NAME")); customer.setAccountNumber(rs.getLong("CUSTOMER_ACCOUNT_NO")); map.put(id, customer); } int type = rs.getInt("IS_BRAND"); if(type == 1) { List brandList = customer.getBrands(); if(brandsList == null) { brandsList = new ArrayList<Brand>(); customer.setBrands(brandsList); } Brand brand = new Brand(); brand.setId(rs.getLong("COL_A")); brand.setName(rs.getString("COL_B")); brandsList.add(brand); } else if(type == 0) { List ordersList = customer.getOrders(); if(ordersList == null) { ordersList = new ArrayList<Order>(); customer.setOrders(ordersList); } Order order = new Order(); order.setId(rs.getLong("COL_A")); ordersList.add(order); } } return new ArrayList<Customer>(map.values()); }}
