Java 从弹簧靴映射到角度映射

我有一个SpringBootRESTAPI，它向我发送一个带有键和值的映射，作为POJO，例如某个报告的映射。我试着把它放在有角度的前端。问题来了。 通常，当我得到像Collection angular这样的数组时，会自动将Doctor POJO从angular转换为我的Doctor类。但是对于贴图有一个问题，键没有被转换，它们只是作为字符串出现，即使值被正确解码，并且它们被转换到我的angular类

Rest控制器端点：

 @GetMapping(value = "/doctors/reports")
public Map<HospitalDTO, DoctorsDTO> handleGroupDoctorsByHospital() {
    var doctorsReport = service.groupDoctorsByHospital();
    Map<HospitalDTO, DoctorsDTO> doctorsReportDto = new HashMap<>();
    doctorsReport.forEach((hospital, doctors) -> doctorsReportDto.put(
            hospitalConverter.convertModelToDto(hospital),
            new DoctorsDTO(doctors.stream().map(doctorConverter::convertModelToDto).collect(Collectors.toSet()))
    ));
    return doctorsReportDto;
}

医生：

@EqualsAndHashCode(callSuper = true)
@NoArgsConstructor
@AllArgsConstructor
@Data
public class DoctorsDTO extends BaseDto{
    Set<DoctorDTO> doctors;
}

角度等级：

export class Doctor{
  id: number;
  fullName: string;
  practicingSince: string;
  hospitalId: number;

  constructor(id: number, fullName: string, practicingSince: string, hospitalId: number) {
    this.id = id;
    this.fullName = fullName;
    this.practicingSince = practicingSince;
    this.hospitalId = hospitalId;
  }
}

我在这里处理请求：

getReport(): Observable<Map<Hospital, Doctor[]>>{
    return this.http.get<Map<Hospital, Doctor[]>>(this.doctorURL + '/reports');
  }

然而，我需要的关键也是我的角度类型的对象。即使在这个映射上进行迭代也无法完成，我会得到如下错误：响应没有forEach函数，或者响应没有forEach函数。values（）不是iterable集

export class Doctor{
  id: number;
  fullName: string;
  practicingSince: string;
  hospitalId: number;

  constructor(id: number, fullName: string, practicingSince: string, hospitalId: number) {
    this.id = id;
    this.fullName = fullName;
    this.practicingSince = practicingSince;
    this.hospitalId = hospitalId;
  }
}

export class Hospital{
  id: number;
  capacity: number;
  name: string;
  address: string;

  constructor(id: number, capacity: number, name: string, address: string) {
    this.id = id;
    this.capacity = capacity;
    this.name = name;
    this.address = address;
  }
}

getReport(): Observable<Map<Hospital, Doctor[]>>{
    return this.http.get<Map<Hospital, Doctor[]>>(this.doctorURL + '/reports');
  }

{
    "HospitalDTO(super=BaseDto(id=1), capacity=20, name=angular hospital, address=angular address)": {
        "id": null,
        "doctors": [
            {
                "id": 1,
                "fullName": "testDoctor1",
                "practicingSince": "2000-01-01",
                "hospitalId": 1
            }
        ]
    },
    "HospitalDTO(super=BaseDto(id=3), capacity=20, name=angular hospital 2, address=angular address 2)": {
        "id": null,
        "doctors": [
            {
                "id": 3,
                "fullName": "front-end",
                "practicingSince": "2018-02-01",
                "hospitalId": 3
            }
        ]
    },
    "HospitalDTO(super=BaseDto(id=2), capacity=20, name=second, address=second)": {
        "id": null,
        "doctors": [
            {
                "id": 2,
                "fullName": "testDoctor2",
                "practicingSince": "2000-02-01",
                "hospitalId": 2
            }
        ]
    }
}