我有一个实体的List
。
使用Spring MVC 4和Spring Data JPA,如何将其转换为Page
对象?
我有一个实体的List
。
使用Spring MVC 4和Spring Data JPA,如何将其转换为Page
对象?
有一个Page
的实现:
final Page<Something> page = new PageImpl<>(theListOfSomething);
还有一个构造函数:
Page<Something> page = new PageImpl<>(listOfsomething, pageable, listOfsomething.size());
Pageable pageable = PageRequest.of(pageNumber, size);
,请注意pageNumber
是“从零开始”的,而且Pageable
和PageRequest
都需要从 org.springframework.data.domain
中导入。更多信息请查看 可分页文档。 - Aleksandar我认为你还需要获取正确的页面内容。
PageRequest pageRequest = PageRequest.of(offset, limit);
List<Product> products = getProducts();
int total = products.size();
int start = toIntExact(pageRequest.getOffset());
int end = Math.min((start + pageRequest.getPageSize()), total);
List<Product> output = new ArrayList<>();
if (start <= end) {
output = products.subList(start, end);
}
return new PageImpl<>(
output,
pageRequest,
total
);
Pageable
对象作为参数。这个Pageable
对象包含了页码、页面大小和排序信息。Page
对象:List<Entity> allList = jpaRepository.findAll(pageable.getSort());
List<Entity> pageList = allList.stream()
.skip(pageable.getOffset())
.limit(pageable.getPageSize())
.collect(Collectors.toList());
return new PageImpl<>(pageList, pageable, allList.size());
public Page<?> toPage(List<?> list, Pageable pageable) {
int start = (int) pageable.getOffset();
int end = Math.min((start + pageable.getPageSize()), list.size());
if(start > list.size())
return new PageImpl<>(new ArrayList<>(), pageable, list.size());
return new PageImpl<>(list.subList(start, end), pageable, list.size());
}
//pageNum starts with 1
//size: page size
//totalRecords, total records
Page<Record> myMethod(int pageNum, int size, List<MyRecord> totalRecords){
if(pageNum<1){
pageNum = 1;
}
if(size < 1){
size = 10;
}
//spring page starts with 0
Pageable pageable = new PageRequest(pageNum-1, size);
//when pageNum * size is too big(bigger than list.size()), totalRecords.subList() will throw a exception, we need to fix this
if(pageable.getOffset() > list.size()){
pageable = new PageRequest(0, size);
}
List<MyRecord> pageRecords = totalRecords.subList(pageable.getOffset(), Math.min(pageable.getOffset() + pageable.getPageSize(), totalRecords.size()));
Page springPage = new PageImpl<>(pageRecords, pageable, totalRecords.size());
return springPage;
}
public static <T> PageData buildCustomPagedData(List<T> data, Pageable pageable) {
List<T> model = new ArrayList<>();
int start = VALUE_ZERO;
if (!Objects.equals(pageable.getPageNumber(), FIRST_INDEX)) {
start = (pageable.getPageNumber() * pageable.getPageSize());
}
for (int i = start; i < start + pageable.getPageSize(); i++) {
if (i < data.size()) {
model.add(data.get(i));
} else {
break;
}
}
return PageData.builder()
.model(model)
.totalElements(data.size())
.currentPage(pageable.getPageNumber() + INT_ONE)
.totalPages((data.size() / pageable.getPageSize()) + INT_ONE)
.build();
}