可选的 Spring 分页 [英] Optional pagination with Spring

问题描述

我对 Java 和 Spring 还很陌生.

I am pretty new to java and spring.

我想要实现的是带有分页和排序功能的 api 端点 /tickets.我做到了，而且有效.但如果查询参数中未指定 size 和 page ，我想做的是返回所有票证的普通列表，因此在 FE 中我可以使用该列表在选择框中.

What I want to implement is api endpoint /tickets with pagination and sorting. I made it and it works. But also what I would like to do is to return plain list of all tickets if size and page are not specified in the query params, so in FE I can use that list in selectbox.

我试图做的是在服务外观上实现 getTickets 并返回所有票证的列表.但是我没有找到如何检查是否设置了 Pageable 的方法，因为它总是返回默认值 (size=20, page=0)

What I have tried to do is to implement getTickets on service facade and return list of all tickets. But I didn't find a way how to check if Pageable is set as it always returns default values (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

//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());
}

也许我做错了?

推荐答案

如果你像这样构建你的控制器方法，你可以通过检查请求参数来管理是否要实现分页:

If you build out your controller method like so, you can manage whether or not you want to implement paging by checking the request params:

@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 以传递给您的服务方法，您可以像这样手动执行:

If you need to build a PageRequest to pass into your service method, you can do so manually like so:

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

这篇关于可选的 Spring 分页的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！