java - 从 Rest API 返回带有值的键

Question

我想从 Rest API 端点返回 JSON 作为带有值的键。示例:

  {
    "terminal 1":
       {"date":"2018-10-06T00:00:00.000+0000","volume":111,"count":1},
    "terminal 2":
       {"date":"2018-11-06T00:00:00.000+0000","volume":122,"count":1}
  }

如何添加 key ？我想应该是这样的:

List<String<List<TopTerminalsDTO>>>>

你能给我一些代码示例吗？

清理最终代码的最新尝试:

@GetMapping("/terminals")
public ResponseEntity<Map<Integer, List<TopTerminalsDTO>>> getTopTerminalsVolumes(
        @RequestParam(value = "start_date", required = true) String start_date,
        @RequestParam(value = "end_date", required = true) String end_date) {

        LocalDateTime start_datel = LocalDateTime.now(Clock.systemUTC());
        LocalDateTime end_datel = LocalDateTime.now(Clock.systemUTC());

        final List<PaymentTransactionsDailyFacts> list = dashboardRepository.top_daily_transactions(start_datel, end_datel);

        final Collector<PaymentTransactionsDailyFacts, List<TopTerminalsDTO>, List<TopTerminalsDTO>> terminalsCollector =
                 Collector.of(
                    ArrayList::new,
                    (terminals, p) -> terminals.add(mapper.toTopTerminalsDTO(p)),
                    (accumulator, terminals) -> {
                       accumulator.addAll(terminals);
                       return accumulator;
                    }
                 );

        final Map<Integer, List<TopTerminalsDTO>> final_map = 
                     list.stream()
                         .filter(p -> p.getTerminal_id() != null)
                         .collect(Collectors.groupingBy(p -> p.getTerminal_id(), terminalsCollector));

    return ResponseEntity.ok(final_map);
}

Answer 1

按照您的 JSON，testDate()应该返回 Map<String, TopTerminalsDTO>而不是 List .

Map<String, TopTerminalsDTO> result = newHashMap();

for (int i = 0; i <= 10; i++) {

    TopTerminalsDTO ttDto = new TopTerminalsDTO();
    ttDto.setCount(ThreadLocalRandom.current().nextInt(20, 500 + 1));

    LocalDate localDate = LocalDate.now().minus(Period.ofDays((new Random().nextInt(365 * 70))));
    Date date = Date.from(localDate.atStartOfDay(ZoneId.systemDefault()).toInstant());

    ttDto.setDate(date);
    ttDto.setVolume(ThreadLocalRandom.current().nextInt(300, 5000 + 1));

    result.put("terminal "+i, ttDto)
}

return result;

当然，将 rest 方法的响应类型更改为 ResponseEntity<Map<String, TopTerminalsDTO>>