我面临分页数据的问题。页面数据是使用外部数组dXPRecommendationResponses
计算的,我希望它应该通过嵌套数组recommendations
计算。我在结果部分提到了响应数据。
我尝试更改页面数据计算,但它是使用我们在 PageImpl()
构造函数中传递的数据来计算的。
我使用这种方法对从第三方 API 获取的数据进行分页。
但它是使用dxpRecommendationslist
计算的。
#This is the code through I need to generate the response
List<DXPRecommendationResponse> dxpRecommendationslist = new ArrayList<>();
List<DXPActivity> dxpActivities = getThirdResponse(pageable, correlationId,
dxpRecommendationslist, reservationGuestId, reservationId, nbxRecommendationRequest);
return new PageImpl<>(dxpRecommendationslist, pageable, dxpActivities.size());
#This method is used to get data from third party
public List<DXPActivity> getThirdResponse(final Pageable pageable, final String correlationId,
List<DXPRecommendationResponse> list, String reservationGuestId, String reservationId,
NBXRecommendationRequest nbxRecommendationRequest) {
List<DXPActivity> dxpActivities = new ArrayList<>();
NBXRecommendationResponse nbxRecommendationResponse = vVNBXRecommendationService
.getCalendarRecommendation(nbxRecommendationRequest, correlationId);
if (nbxRecommendationResponse != null) {
DXPRecommendationResponse dxpRecommendationResponse = new DXPRecommendationResponse();
dxpRecommendationResponse.setReservationGuestId(reservationGuestId);
dxpRecommendationResponse.setReservationNumber(reservationId);
dxpRecommendationResponse.setRecommendationType("CalendarType");
dxpRecommendationResponse.setDateTime(new Date());
populateActivities(dxpActivities, nbxRecommendationResponse);
List<DXPActivity> filteredList;
if (!CollectionUtils.isEmpty(dxpActivities)
&& dxpActivities.size() >= (pageable.getPageSize() * pageable.getPageNumber())) {
filteredList = Lists.partition(dxpActivities, pageable.getPageSize()).get(pageable.getPageNumber());
} else {
filteredList = new ArrayList<DXPActivity>();
}
dxpRecommendationResponse.setRecommendations(filteredList);
list.add(dxpRecommendationResponse);
}
return dxpActivities;
}
#This method is used to populate data
private void populateActivities(List<DXPActivity> dxpActivities,
NBXRecommendationResponse nbxRecommendationResponse) {
for (Activity activity :nbxRecommendationResponse.getCalendarRecommendation().getRecommendations().getActivities()) {
DXPActivity dxpActivity = new DXPActivity();
orikaMapper.map(activity, dxpActivity);
dxpActivities.add(dxpActivity);
}
}
响应数据:
{
"_embedded": {
"dXPRecommendationResponses": [
{
"recommendationType": "CalendarType",
"reservationGuestId": "525dab66-1492-4908-a3bf-b5de558368e5",
"reservationNumber": "3a39f9ad-7e34-4bdb-91eb-b907fd6986c7",
"dateTime": "2019-08-19T14:38:18.413",
"recommendations": [
{
"productCode": "BIKE2006111000",
"activityName": "Bimini Bike Tour",
"recommendationId": "1565948843492_410387839_BIKE2006111000_cal",
"categoryCode": "DARING",
"activityStartTime": "2020-06-11T08:30:00.000",
"activityEndTime": "2020-06-11T11:30:00.000",
"activityDescription": "Bimini Bike Tour",
"sequence": 34.0,
"packageId": 103806,
"sourceId": "BIMINI BIKE",
"levelOfActivity": "EASY"
},
{
"productCode": "CUL2006110900",
"activityName": "Bimini Culinary Tour",
"recommendationId":"156594884349,
"categoryCode": "CULTURED",
"activityStartTime": "2020-06-11T07:30:00.000",
"activityEndTime": "2020-06-11T12:30:00.000",
"activityDescription": "Bimini Culinary Tour",
"sequence": 29.0,
"packageId": 103940,
"sourceId": "BIMINI CUL",
"levelOfActivity": "MODERATE"
}
]
}
]
},
"page": {
"size": 10,
"totalElements": 1,
"totalPages": 1,
"number": 0
}
}
最佳答案
这里的问题是 PageImpl
的实现constructor以及如何在此处计算结果总数。下面是从构造函数中获取的代码:
this.total = pageable.toOptional().filter(it -> !content.isEmpty())//
.filter(it -> it.getOffset() + it.getPageSize() > total)//
.map(it -> it.getOffset() + content.size())//
.orElse(total);
这里重要的一行是第二行,如文档注释中所述,它是防止不一致的保险。它检查您是否在最后一页,如果是,它将使用第三行来计算结果 total
。因此完全省略total
你给的。如果您想重写此行为,您应该实现您的 Page
仅使用给定的 total
.
但是,我认为它在语义上不正确。您正在将可能不应该混合的东西混合在一起(一种类型的页面对象,但在另一种类型上完成的实际分页)。作为可分页给出的列表始终有一个元素,而您正在对子元素进行分页,这似乎不正确,是否还需要对子元素进行分页?
可能的解决方案之一是通过指定 Page<DXPActivity> recommendations
使子元素仅可分页。直接里面成员(member)DXPRecommendationResponse
并返回不可分页的 DXPRecommendationResponse
。但话又说回来,似乎有点不对劲。这实际上取决于您想要在这里构建什么以及其背后的逻辑是什么。
关于java - Spring Boot 分页,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/57567849/