PersistentObjectException：分离的实体传递给持久化[JpaRepository] ​​

Question

我正在将Spring Data JPA与JpaRepository一起使用，但找不到为什么我的实体被分离并且我无法使用子实体保存的答案。

我想保存配方，但首先我需要将成分保存在另一项服务中。配方和成分通过RecipeIngredients对象建立了多对多关系。

@Transactional
public RecipeDto updateRecipe(UserPrincipal userPrincipal, String recipeName, RecipeDto recipeDto) {
            Recipe recipeToEdit = recipeRepository.findByName(recipeName).orElseThrow(EntityNotFoundException::new);
            recipeToEdit.setIngredients(recipeIngredientsService.refillRecipeIngredientsList(recipeDto.getIngredients(), recipeToEdit));
}

@Entity
public class RecipeIngredients {

    @EmbeddedId
    private RecipeIngredientsId recipeIngredientsId;

    @ManyToOne(fetch = FetchType.LAZY)
    @MapsId("recipeId")
    @ToString.Exclude
    private Recipe recipe;

    @ManyToOne(fetch = FetchType.LAZY, cascade = {CascadeType.MERGE})
    @MapsId("ingredientId")
    @ToString.Exclude
    private Ingredient ingredient;
}

@Entity
@Getter
@Setter
public class Ingredient {

@Id
    @Column(name = "id", updatable = false)
    private Long id;
    @OneToMany(mappedBy = "ingredient", cascade = CascadeType.ALL, orphanRemoval = true)
    @ToString.Exclude
    private List<RecipeIngredients> recipeIngredients;

    public void addRecipeIngredient(RecipeIngredients recipeIngredient) {
        if(recipeIngredients == null) {
            recipeIngredients = new ArrayList<>();
        }
        recipeIngredients.add(recipeIngredient);
        recipeIngredient.setIngredient(this);
    }
}

在我要保存 Ingredient 实体之前，我要检查是否存在，因此我从外部服务中将其拉出，然后将其映射到DTO对象。如果没有成分，我要保存并获取他的对象，该对象将与 RecipeIngredients 的子级关联，并且此对象与 Recipe 相关，因此当我正在保存食谱，它应该为我保存 RecipeIngredient 。

public void refillRecipeIngredientsList(List<RecipeIngredientsDto> recipeIngredientsDtos, Recipe recipe) {
    removeOldIngredientsIfExist(recipe);
    if (recipeIngredientsDtos != null) {
        for (RecipeIngredientsDto recipeIngredientsDto : recipeIngredientsDtos) {
            IngredientDto ingredient = pullSavedIngredient(recipeIngredientsDto);
            RecipeIngredients recipeIngredient = this.recipeIngredientsDtoToEntityMapper.recipeIngredientsToEntity(recipeIngredientsDto, recipe, ingredientDto);
            recipe.addIngredient(recipeIngredient);
            ingredient.addRecipeIngredient(recipeIngredient);
        }
    }
}

但是我以各种方式收到了org.hibernate.PersistentObjectException: detached entity passed to persist: com.app.todaysdinner.entity.ingredient.Ingredient。有人知道答案如何重新附加成分实体吗？

[编辑]

我发现，当我想通过Recipe上的RecipeIngredients级联进行更新时，还要级联到Ingredients上，这意味着即使仅允许cascade = {CascadeType.MERGE}，它也会调用PERSISTANCE方法。但是我找不到答案，为什么在一个@Transaction对象中被分离。