优化Java中列表元素映射与批量更新策略

private Item getItemManufacturerPriceCodes(Item item) {
    List<ItemPriceCode> itemPriceCodes = item.getItemPriceCodes();

    // 问题：在循环内部为每个ItemPriceCode执行一次数据库查询
    for (ItemPriceCode ipc : itemPriceCodes) {
        Optional<ManufacturerPriceCodes> mpc = manufacturerPriceCodesRepository.findByManufacturerIDAndPriceCodeAndRecordDeleted(
                item.getManufacturerID(), ipc.getPriceCode(), NOT_DELETED);
        if (mpc.isPresent()) {
            ipc.setManufacturerPriceCode(mpc.get().getName());
        }
    }

    item.getItemPriceCodes().removeIf(ipc -> DELETED.equals(ipc.getRecordDeleted()));
    return item;
}

// ManufacturerPriceCodesRepository.java
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.Query;
import org.springframework.data.repository.query.Param;
import java.util.List;

public interface ManufacturerPriceCodesRepository extends JpaRepository<ManufacturerPriceCodes, Long> {

    /**
     * 根据制造商ID、记录状态和一批价格代码查询对应的制造商价格代码名称。
     * 返回一个Object数组列表，每个数组包含ItemPriceCode的ID和ManufacturerPriceCodes的名称。
     *
     * @param manufacturerId 制造商ID
     * @param recordDeleted 记录删除状态
     * @param priceCodes ItemPriceCode对象列表，用于匹配其priceCode属性
     * @return 包含ItemPriceCode ID和ManufacturerPriceCodes名称的Object数组列表
     */
    @Query("SELECT ipc.id, mpc.name FROM ManufacturerPriceCodes mpc JOIN mpc.priceCode ipc " +
           "WHERE mpc.manufacturerID = :manufacturerId AND ipc.priceCode IN (:priceCodes) AND mpc.recordDeleted = :recordDeleted")
    List<Object[]> findMFPNameByManufacturerIdAndRecordDeletedAndPriceCodes(
            @Param("manufacturerId") String manufacturerId,
            @Param("recordDeleted") <TypeForRecordDeleted> recordDeleted, // 替换为实际类型，如Boolean或Integer
            @Param("priceCodes") List<String> priceCodes); // 注意这里需要传入List<String>而不是List<ItemPriceCode>
}

import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

public class ItemService { // 假设这是一个服务类
    // ... 注入 manufacturerPriceCodesRepository

    private Item getItemManufacturerPriceCodes(Item item) {
        List<ItemPriceCode> itemPriceCodes = item.getItemPriceCodes();

        // 1. 从ItemPriceCode列表中提取所有priceCode
        List<String> priceCodeStrings = itemPriceCodes.stream()
                .map(ItemPriceCode::getPriceCode)
                .collect(Collectors.toList());

        // 2. 执行批量查询，一次性获取所有相关的ManufacturerPriceCodes名称
        // 假设NOT_DELETED是常量，例如Boolean.FALSE或0
        List<Object[]> keyPairs = manufacturerPriceCodesRepository.findMFPNameByManufacturerIdAndRecordDeletedAndPriceCodes(
                item.getManufacturerID(), NOT_DELETED, priceCodeStrings);

        // 3. 将查询结果转换为Map，方便快速查找
        // Map的key是ItemPriceCode的ID，value是ManufacturerPriceCodes的名称
        Map<String, String> ipcIdToMFPNameMap = keyPairs.stream()
                .collect(Collectors.toMap(
                        arr -> (String) arr[0], // 假设ItemPriceCode的ID是String类型
                        arr -> (String) arr[1]  // 假设ManufacturerPriceCodes的名称是String类型
                ));

        // 4. 遍历ItemPriceCode列表，使用Map进行高效更新
        itemPriceCodes.forEach(ipc -> {
            String manufacturerPriceCodeName = ipcIdToMFPNameMap.get(ipc.getId()); // 假设ItemPriceCode有getId()方法
            if (manufacturerPriceCodeName != null) {
                ipc.setManufacturerPriceCode(manufacturerPriceCodeName);
            }
        });

        // 5. 移除已删除的ItemPriceCode（这部分逻辑保持不变）
        item.getItemPriceCodes().removeIf(ipc -> DELETED.equals(ipc.getRecordDeleted()));

        return item;
    }
}