java - 如何将包含内容的 TreeMap 转换为 JSON 格式 Spring REST Controller JAVA

Question

您好，我有一个代码，我想将我的集合公开为 JSON 格式。我以为Spring会自动完成它。这是代码:

@RestController
    public class BirthdayController  extends BaseController{

        @RequestMapping("/api/v1/birthday")
        public TreeMap<Integer, TreeMap<Integer, ArrayList<BirthdayDetails>>> getBirthdays(@RequestParam(value="startYear") Integer startYear,
                                  @RequestParam(value="startMonth") Integer startMonth,
                                  @RequestParam(value="endYear") Integer endMonth,
                                  @RequestParam(value="endMonth") Integer endYear) {
            BirthdayServiceImpl birthdayService = new BirthdayServiceImpl();
            return birthdayService.getBirthdaysBetweenDate(startMonth, startYear, endMonth, endYear);
        }
    }

访问端点时我只得到空的 {}

Answer 1

尝试，

@RequestMapping("/api/v1/birthday")
        public @ResponseBody TreeMap<Integer, TreeMap<Integer, ArrayList<BirthdayDetails>>> getBirthdays(@RequestParam(value="startYear") Integer startYear,
                                  @RequestParam(value="startMonth") Integer startMonth,
                                  @RequestParam(value="endYear") Integer endMonth,
                                  @RequestParam(value="endMonth") Integer endYear) {
            BirthdayServiceImpl birthdayService = new BirthdayServiceImpl();
            return birthdayService.getBirthdaysBetweenDate(startMonth, startYear, endMonth, endYear);
        }