可选的Spring分页

Question

我是java和spring的新手.

我想要实现的是/tickets具有分页和排序的api端点.我做了它,它的工作原理.但也是我想做的是,如果返回所有门票的普通列表size,并page没有在查询参数指定的,所以在FE我可以使用选择框该列表.

我试图做的是getTickets在服务门面上实现并返回所有门票的列表.但我找不到如何检查Pageable是否设置的方法,因为它始终返回默认值(size = 20,page = 0)

//控制器

@RequestMapping(method = RequestMethod.GET)
public ResponseEntity<Page<TicketListItemResponseModel>> getTickets(Pageable pageable) {
    logger.info("> getTickets");
    Page<TicketListItemResponseModel> tickets = ticketServiceFacade.getTickets(pageable);
    logger.info("< getTickets");
    return new ResponseEntity<>(tickets, HttpStatus.OK);
}

// TicketServiceFacade

public Page<TicketListItemResponseModel> getTickets(Pageable pageable) {
    Page<Ticket> tickets = ticketService.findAll(pageable);
    return tickets.map(new ConverterFromPagesToListItem());
}

public List<TicketListItemResponseModel> getTickets() {
    List<Ticket> tickets = ticketService.findAll();
    return tickets.stream()
            .map(t -> modelMapper.map(t, TicketListItemResponseModel.class))
            .collect(Collectors.toList());
}

也许我完全错了？

Answer 1

如果像这样构建控制器方法，则可以通过检查请求参数来管理是否要实现分页：

@Override
public ResponseEntity<Page<TicketListItemResponseModel>> getTickets(
        @RequestParam(value = "page", defaultValue = "0", required = false) int page,
        @RequestParam(value = "count", defaultValue = "10", required = false) int size,
        @RequestParam(value = "order", defaultValue = "ASC", required = false) Sort.Direction direction,
        @RequestParam(value = "sort", defaultValue = "name", required = false) String sortProperty) {
    // here you would check your request params and decide whether or not to do paging and then return what you need to return
}

如果您需要构建一个PageRequest来传递到您的服务方法中，则可以像这样手动进行：

new PageRequest(page, size, new Sort(direction, sortProperty));