objectity如何處理其他實體內的實體

Question

早上好，我正在更新我的appengine後端與Android應用程序中的對象，我從asincona類調用後端。 閱讀了幾個教程後，我設法獲取，更新，插入和刪除一個實體，但是這個實體包含另一種類型的實體的數組列表，並且當我想要做一個get時，沒有問題，因爲主實體給我訪問實體列表，我甚至設法插入，但在更新和刪除時，我無法讓它工作。

例如實體用戶照片的實體列表：

@Entity 
public class UserEntity { 
@Id 
String id; 
private String mail; 
private String name; 
private ArrayList<PhotoEntity> listPhotos = new ArrayList<>(); 

//constructor 
public UserEntity(){} 

getters & setters.... 
} 

照片實體：

@Entity 
public class PhotoEntity { 
@Id 
Long id; 
private String author; 
private int height; 
private int widht; 
private Blob image; 

//constructor 
public PotoEntity() {} 

getters & setters..... 
} 

的UserEntity端點

插入方法的工作原理：

@ApiMethod(
     name = "insertUserPhoto", 
     path = "userEntityPhoto", 
     httpMethod = ApiMethod.HttpMethod.POST) 
public UserEntity insertUserPhoto(@Named("idUser")String idUser, UserPhotoEntity userPhoto) throws NotFoundException { 
    UserEntity userEntity = null; 
    userEntity = ofy().load().type(UserEntity.class).id(idUser).now(); 
    if (userEntity == null) { 
     throw new NotFoundException("Could not find UserEntity with ID: " + idUser); 
    } 
    userEntity.getListPhotos().add(userPhoto); 
    ofy().save().entity(userEntity).now(); 
    logger.info("Created UserPhotoEntity with ID: " + userPhoto.getId()); 

    return ofy().load().entity(userEntity).now(); 
} 

的更新方法不起作用：

@ApiMethod(
     name = "updateUserPhoto", 
     path = "userEntityPhoto/{id}", 
     httpMethod = ApiMethod.HttpMethod.PUT) 
public UserEntity updateUserPhoto(@Named("idUser") String idUser, 
              @Named("idPhoto") String idPhoto) throws Exception { 

    UserEntity userEntity = null; 
    UserPhotoEntity userPhotoTemp = null; 

    userEntity = ofy().load().type(UserEntity.class).id(idUser).now(); 
    if (usuarioEntity == null) { 
     throw new NotFoundException("Could not find UserEntity with ID: " + idUser); 
    } 

    for(int i = 0; i < userEntity.getListPhotos().size(); i++){ 
     if(userEntity.getListPhotos().get(i).getId().equalsIgnoreCase(idPhoto)){ 
      userPhotoTemp = userEntity.getListPhotos().get(i); 
      userPhotoTemp.setAuthor("code changed"); 

      userEntity.getListPhotos().get(i).remove(); 
      userEntity.getListPhotos().add(userPhotoTemp); 

      ofy().save().entity(userEntity).now(); 
      break; 
     } 
    } 

    logger.info("Updated UserPhotoEntity: " + userEntity); 
    return ofy().load().entity(userEntity).now(); 
} 

刪除方法不起作用：

@ApiMethod(
     name = "removeUserPhoto", 
     path = "userEntityPhoto/{id}", 
     httpMethod = ApiMethod.HttpMethod.DELETE) 
public void removeUserPhoto(@Named("idUser") String idUser, 
           @Named("idPhoto") String idPhoto) throws NotFoundException { 

    UserEntity userEntity = null; 

    userEntity = ofy().load().type(UserEntity.class).id(idUser).now(); 
    if (userEntity == null) { 
     throw new NotFoundException("Could not find UserEntity with ID: " + idUser); 
    } 

    for(UserPhotoEntity upe : userEntity.getListPhotos()){ 
     if(upe.getId().equalsIgnoreCase(idPhoto)){ 
      ofy().delete().entities(upe); 
      break; 
     } 
    } 

    logger.info("Deleted UserEntity with ID: " + idPhoto); 
} 

有人能幫助我，我該怎麼辦端點方法時，有實體的名單？

謝謝。

Answer 1

，將創造和嵌入式實體，我建議您改爲參考：

@Entity 
public class UserEntity { 
@Id 
String id; 
private String mail; 
private String name; 
private List<Ref<PhotoEntity>> photoEntity= new ArrayList<Ref<PhotoEntity>>();