按数组列表自定义分页

我想在java代码中创建一个数组列表的自定义分页

import org.springframework.data.domain.Sort; import org.springframework.data.domain.PageRequest; import org.springframework.data.domain.Page; import org.springframework.data.domain.PageImpl; import org.springframework.data.domain.Sort.Direction; ... int page = 0; int count = 8; String sortOrder = "desc"; String sortBy = "id"; Sort sort = new Sort(Direction.fromString(sortOrder), sortBy); PageRequest pageable = new PageRequest(page, count, sort); List impiantos = myService.findMyMethod(); // returned 30 objects Page pageImpianto = new PageImpl(impiantos, pageable, impiantos.size()); 

上面的脚本不会返回包含8个元素的页面。 为什么？

NB列表没有从db返回

你能帮助我吗？

Answer 1

我解决了这个解决方法。

  import org.springframework.data.domain.Sort; import org.springframework.data.domain.PageRequest; import org.springframework.data.domain.Page; import org.springframework.data.domain.PageImpl; import org.springframework.data.domain.Sort.Direction; ... int page = 0; int count = 8; String sortOrder = "desc"; String sortBy = "id"; Sort sort = new Sort(Direction.fromString(sortOrder), sortBy); PageRequest pageable = new PageRequest(page, count, sort); List impiantos = myService.findMyMethod(); // returned 30 objects int max = (count*(page+1)>impiantos.size())? impiantos.size(): count*(page+1); Page pageImpianto = new PageImpl(impiantos.subList(page*count, max), pageable, impiantos.size()); 

我实现了一个新的自定义比较器类

 import java.lang.reflect.Field; import java.util.Comparator; import java.util.Date; public class MyListComparator implements Comparator 

Answer 2

我根据您自己的代码制作了自己的代码，以满足客户的要求，没有任何排序等等。谢谢

这就是Controller的样子

  @RequestMapping(value="/zonas", method = RequestMethod.GET) public String zonas(ModelMap modelMap, @PageableDefault(size=3) Pageable pageable, ZonasFilter zonasFilter, Locale locale) { LOGGER.info("Cargando la vista del índice de Zonas."); List zonas; try { zonas = zonasService.loadAll(); int max = (pageable.getPageSize()*(pageable.getPageNumber()+1)>zonas.size())? zonas.size(): pageable.getPageSize()*(pageable.getPageNumber()+1); modelMap.addAttribute("zonas",new PageImpl(zonas.subList(pageable.getPageSize()*pageable.getPageNumber(), max), pageable, zonas.size())); } catch (ApiException e) { // TODO Auto-generated catch block e.printStackTrace(); List errors=e.getErrors(); for (ApiError apiError : errors) { modelMap.addAttribute("error", messages.getMessage(apiError.getMessage(), null, locale)); } } LOGGER.info("Vista del índice de Zonascargada."); return "zonas/index"; } 

Answer 3

Flavio Troia’answer是错误的，当impiantos小于count并且页面大于1时，调用subList函数会出现exception，fromIndex（10）> toIndex（5），我自己创建了这样的代码，它可能是冗余，但对我来说，它很容易理解和正确〜

  List shopCourseBizPojos = addCourseCoupons(mcCouponLists, shopCourseLists); if (pageable.getOffset() > shopCourseBizPojos.size()) { long total = 0L; PageImpl emptyPage = new PageImpl<>(Lists.newArrayList(), pageable, total); resultDo.setResult(emptyPage); return resultDo; } if (pageable.getOffset() <= shopCourseBizPojos.size() && pageable.getOffset() + pageable.getPageSize() > shopCourseBizPojos.size()) { List bizPojos = shopCourseBizPojos.subList(pageable.getOffset(), shopCourseBizPojos.size()); PageImpl pPage = new PageImpl<>(bizPojos, pageable, shopCourseLists.size()); resultDo.setResult(pPage); return resultDo; } List ucShopCourseBizPojos = shopCourseBizPojos.subList(pageable.getOffset(), pageable.getOffset() + pageable.getPageSize()); PageImpl pPage = new PageImpl<>(ucShopCourseBizPojos, pageable, shopCourseLists.size()); resultDo.setResult(pPage); return resultDo;