Spring PagingAndSortingRepository - 按名称查找 [英] Spring PagingAndSortingRepository - find by name
问题描述
问题：我试图在网格中只加载国名为购买订单...让我们说爱尔兰。事情是我真的不知道这是否可能。
到目前为止，我已经尝试将服务类 executeQueryFindAll（）中的方法更改为这样的内容。
私人网页< PurchaseOrder> executeQueryFindAll（int page，int maxResults）{
final PageRequest pageRequest = new PageRequest（page，maxResults，sortByNameASC（））;
页面< PurchaseOrder> purchaseOrders = purchaseOrderRepository.findAll（pageRequest）;
页< PurchaseOrder> selectedPurchaseOrders =新页面< PurchaseOrder>（）; //不能实例化页面是抽象
（PurchaseOrder next：purchaseOrders）{
if（next.getCountry（）。getCountryname（）。toString（）。equals（Ireland））
selectedPurchaseOrders.add（next）; //这是跛脚，因为不是LIST，所以它不会工作
}
return selectedPurchaseOrders;
上面的方法不会工作，因为Page是一个抽象类，因此不能被实例化。我可以循环但不能执行 selectedPurchaseOrders.add（next），因为那不是List。在调试模式下，我可以评估 next.getCountry（）。getCountryname（）。toString（），我得到国家名称，这就是为什么我试图比较字符串对象 .equals（Ireland））。
有任何建议吗？
Model
@Entity
@Table（name = PURCHASEORDER，schema =POTOOL）
公共类PurchaseOrder {
@Id
@GeneratedValue
private int id;
//其他PurchaseOrder属性
@ManyToOne（fetch = FetchType.EAGER）
@JoinColumn（name =country_id）
私人国家国家;
// Getter和Setters
存储库
public interface PurchaseOrderRepository扩展
PagingAndSortingRepository< PurchaseOrder，Integer> {
页< PurchaseOrder> findByTowerLike（可分页，字符串名称）;
}
服务
@Service
@Transactional
公共类PurchaseOrderService {
$ b @Autowired
私有PurchaseOrderRepository purchaseOrderRepository;
@Transactional（readOnly = true）
public PurchaseOrderListVO findAll（int page，int maxResults）{
Page< PurchaseOrder> result = executeQueryFindAll（page，maxResults）;
if（shouldExecuteSameQueryInLastPage（page，result））{
int lastPage = result.getTotalPages（） - 1;
result = executeQueryFindAll（lastPage，maxResults）;
}
return buildResult（result）;
}
私人网页< PurchaseOrder> executeQueryFindAll（int page，int maxResults）{
final PageRequest pageRequest = new PageRequest（page，maxResults，sortByNameASC（））;
返回purchaseOrderRepository.findAll（pageRequest）;
//其余的类
无论如何，因为这看起来像像一个Spring Data项目，你应该真的阅读文档来看看有什么可能的：
根据是否需要分页，需要在存储库一侧添加一个方法到你的 PurchaseOrderRepository 接口：
页面<&PurchaseOrder的GT; findByCountryCountryName（可分页，字符串名称）;
列表< PurchaseOrder> findByCountryCountryName（String name）;
没有必要创建一个实现，因为Spring Data会这样做，并创建一个基于方法名称。
存储库代理有两种方法从方法名称派生特定于存储的查询
。 它可以直接从方法名称
派生查询，或者使用手动定义的查询。
您只需从服务层调用您的新方法即可：
@Service
@Transactional
公共类PurchaseOrderService {
@Autowired
私人PurchaseOrderRepository purchaseOrderRepository;
....
私人清单< PurchaseOrder> loadByCountry（String country）{
return purchaseOrderRepository.findByCountryCountryName（country）;
}
}
Problem: I am trying to load into the grid only the Purchase Orders for which country name is...let's say Ireland. Thing is that I don't really know if that's possible.
So far I've tried to change the method in the service class executeQueryFindAll() to something like this.
private Page<PurchaseOrder> executeQueryFindAll(int page, int maxResults) {
final PageRequest pageRequest = new PageRequest(page, maxResults, sortByNameASC());
Page<PurchaseOrder> purchaseOrders = purchaseOrderRepository.findAll(pageRequest);
Page<PurchaseOrder> selectedPurchaseOrders = new Page<PurchaseOrder>(); //not possibile to instantiate as Page is abstract
for(PurchaseOrder next : purchaseOrders){
if(next.getCountry().getCountryname().toString().equals("Ireland"))
selectedPurchaseOrders.add(next); //thats lame because is not a LIST so it wont work
}
return selectedPurchaseOrders;
}
The above approach wont work because Page is an abstract class, therefore cannot be instantiated. I can loop through but I can't do selectedPurchaseOrders.add(next) because that's not a List. In debug mode I can evaluate the next.getCountry().getCountryname().toString() and I get the country name and that's why I've tried to compare the String object .equals("Ireland")).
Any suggestion please?
Model
@Entity
@Table(name = "PURCHASEORDER",schema = "POTOOL")
public class PurchaseOrder {
@Id
@GeneratedValue
private int id;
//other PurchaseOrder properties
@ManyToOne(fetch=FetchType.EAGER)
@JoinColumn(name = "country_id")
private Country country;
//Getter and Setters
Repository
public interface PurchaseOrderRepository extends
PagingAndSortingRepository<PurchaseOrder, Integer> {
Page<PurchaseOrder> findByTowerLike(Pageable pageable, String name);
}
Service
@Service
@Transactional
public class PurchaseOrderService {
@Autowired
private PurchaseOrderRepository purchaseOrderRepository;
@Transactional(readOnly = true)
public PurchaseOrderListVO findAll(int page, int maxResults) {
Page<PurchaseOrder> result = executeQueryFindAll(page, maxResults);
if(shouldExecuteSameQueryInLastPage(page, result)){
int lastPage = result.getTotalPages() - 1;
result = executeQueryFindAll(lastPage, maxResults);
}
return buildResult(result);
}
private Page<PurchaseOrder> executeQueryFindAll(int page, int maxResults) {
final PageRequest pageRequest = new PageRequest(page, maxResults, sortByNameASC());
return purchaseOrderRepository.findAll(pageRequest);
}
//rest of the class
解决方案 Why would you want to load all records and filter in memory rather than in the database?
Anyway, as this looks like a Spring Data project you should really read the documentation to see what is possible:
Depending on whether or not you require paging, all you need to do on the repository side is add a method to your PurchaseOrderRepository interface:
Page<PurchaseOrder> findByCountryCountryName(Pageable pageable, String name);
List<PurchaseOrder> findByCountryCountryName(String name);
There is no need to create an implementation as Spring Data will do this and create a query based on the method name.
The repository proxy has two ways to derive a store-specific query
from the method name. It can derive the query from the method name
directly, or by using a manually defined query.
You simply then need to call your new method from your service layer:
@Service
@Transactional
public class PurchaseOrderService {
@Autowired
private PurchaseOrderRepository purchaseOrderRepository;
....
private List<PurchaseOrder> loadByCountry(String country) {
return purchaseOrderRepository.findByCountryCountryName(country);
}
}
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