Java 使用容器实体使用Post方法将值传递给实体列表时出错

我想使用RouteDto和TrainDto将列车实体列表传递给route实体。但列车数据未在数据库中持久化。我还希望自动生成ID。我在控制器类中使用post方法，并使用RouteService从存储库调用save方法

RouteDto.java

public class RouteDto {

        @GeneratedValue
        @Min(value = 100)
        @Max(value = 999)
        int id;
        @NotEmpty(message="Source cannot be null")
        @Pattern(regexp="^[A-Za-z]+$")
        String source;
        @NotEmpty(message="Destination cannot be null")
        @Pattern(regexp="^[A-Za-z]+$")
        String destination;
        @OneToMany
//      @NotEmpty(message="Train List cannot be null")
        private List<TrainDto> trainList;
        public int getId() {
            return id;
        }
        public void setId(int id) {
            this.id = id;
        }
        public String getSource() {
            return source;
        }
        public void setSource(String source) {
            this.source = source;
        }
        public String getDestination() {
            return destination;
        }
        public void setDestination(String destination) {
            this.destination = destination;
        }
        public List<TrainDto> getTrainList() {
            return trainList;
        }
        public void setTrainList(List<TrainDto> trainList) {
            this.trainList = trainList;
        }
        public RouteEntity createEntity() {
            RouteEntity routeEntity=new RouteEntity();
            routeEntity.setId(this.getId());
            routeEntity.setSource(this.getSource());
            routeEntity.setDestination(this.getDestination());
            List<TrainEntity> trainEntityList=new ArrayList<TrainEntity>();
            List<TrainDto> trainDtoList=this .getTrainList();
            if(trainDtoList!=null) {
                for(TrainDto train:trainDtoList) {
                    trainEntityList.add(train.createEntity());
                }
            }
            routeEntity.setTrainList(trainEntityList);
            return routeEntity;
        }
}

RouteService.java

@Service
public class RouteService {
    @Autowired
    RouteRepository routeRepository;

    public int createRoute(RouteDto route) {
        RouteEntity routeEntity=route.createEntity();
        routeRepository.save(routeEntity);
        return routeEntity.getId();
    }

}

RouteControl.java

@RestController

public class RouteController {
    @Autowired
    RouteService routeService;

    @PostMapping("/routes")
    public ResponseEntity<Integer> createRoute(@Validated @RequestBody RouteDto routeDto){
        int routeId=routeService.createRoute(routeDto);
        return new ResponseEntity<>(routeId, HttpStatus.OK);
    }

}

RouteEntity.java

@Entity
@Table(name="route")
public class RouteEntity {
    @Id
    int id;
    String source;
    String destination;
    @OneToMany
    private List<TrainEntity> trainList;
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getSource() {
        return source;
    }
    public void setSource(String source) {
        this.source = source;
    }
    public String getDestination() {
        return destination;
    }
    public void setDestination(String destination) {
        this.destination = destination;
    }
    public List<TrainEntity> getTrainList() {
        return trainList;
    }
    public void setTrainList(List<TrainEntity> trainList) {
        this.trainList = trainList;
    }

}

@Entity
@Table(name="train")
public class TrainEntity {
    @Id
    @GeneratedValue
    int id;
    String trainName;
    String arrivalTime;
    String departureTime;
    Double fare;
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getTrainName() {
        return trainName;
    }
    public void setTrainName(String trainName) {
        this.trainName = trainName;
    }
    public String getArrivalTime() {
        return arrivalTime;
    }
    public void setArrivalTime(String arrivalTime) {
        this.arrivalTime = arrivalTime;
    }
    public String getDepartureTime() {
        return departureTime;
    }
    public void setDepartureTime(String departureTime) {
        this.departureTime = departureTime;
    }
    public Double getFare() {
        return fare;
    }
    public void setFare(Double fare) {
        this.fare = fare;
    }


}
The train list is coming empty.

---

在

RouteEntity

表中，在id上添加@GeneratedValue以生成id

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
int id;

并添加

CascadeType.ALL

，使列车列表保持不变

@OneToMany(cascade = CascadeType.ALL, orphanRemoval = true)
private List<TrainEntity> trainList;

@OneToMany（cascade=CascadeType.ALL，orphan=true）
私人名单列车名单；

添加实体类请立即检查。如何创建数据库？对于单向关系，需要一个额外的映射表或使用联接列。表route_train_列表自动创建，列route_id和train_id分别得到此错误{“timestamp”：“2020-06-09T20:48:51.998+00:00”，“status”：500，“error”：“Internal Server error”，“trace”：“org.springframework.dao.DataIntegrityViolationException:无法执行语句；SQL[n/a]；约束[PRIMARY]；嵌套异常为org.hibernate.exception.ConstraintViolationException:无法执行语句\r\n\t清除旧数据并重试。可能主键已存在，并且在编译时不在JSONG中发送id。我认为hibernate正在尝试创建名为train_list的列。嵌套异常为org.hibernate.MappingException:Could未确定列：[org.hibernate.mapping.Column（train_List）]的表：route中的java.util.List的类型@SamratDas无法复制，您应该检查更多细节，这是不同的问题，父子同步问题，当您使用双向关系而不是单向关系时发生的。不用担心。如您所愿。我的目的是提供您尝试过的单向解决方案

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
int id;

@OneToMany(cascade = CascadeType.ALL, orphanRemoval = true)
private List<TrainEntity> trainList;