Question

我在配对类中使用findByIngredientId时遇到此问题我在配对结果中无法得到成分（null）。但在调试模式下，该成分被取出。取食材的正确方法是什么？我尝试使用loadAllByProperty，但它无法正常工作。它显示以下错误。这是获取父节点的正确方法吗？

com.food.model.neo.Ingredient["pairings"]->java.util.HashSet[0]->com.food.model.neo.Pairing["first"]->com.food.model.neo.Ingredient["pairings"]->java.util.HashSet[0]->com.food.model.neo.Pairing["first"]->com.food.model.neo.Ingredient["pairings"]->java.util.HashSet[0]->com.food.model.neo.Pairing["first"]->com.food.model.neo.Ingredient["pairings"]->java.util.HashSet[0]->com.food.model.neo.Pairing["first"]->com.food.model.neo.Ingredient["pairings"]->java.util.HashSet[0]->com.food.model.neo.Pairing["first"]->com.food.model.neo.Ingredient["pairings"]->java.util.HashSet[0]->com.food.model.neo.Pairing["first"]->com.food.model.neo.Ingredient["pairings"]->java.util.HashSet[0]->com.food.model.neo.Pairing["first"]->com.food.model.neo.Ingredient["pairings"]->java.util.HashSet[0]->com.food.model.neo.Pairing["first"]->com.food.model.neo.Ingredient["pairings"]->java.util.HashSet[0]->com.food.model.neo.Pairing["first"]->com.food.model.neo.Ingredient["pairings"]->java.util.HashSet[0]->com.food.model.neo.Pairing["first"]->com.food.model.neo.Ingredient["pairings"]->java.util.HashSet[0]->com.food.model.neo.Pairing["first"]->com.food.model.neo.Ingredient["pairings"]->java.util.HashSet[0]->com.food.model.neo.Pairing["first"]->com.food.model.neo.Ingredient["pairings"]->java.util.HashSet[0]->com.food.model.neo.Pairing["first"]->com.food.model.neo.Ingredient["pairings"]->java.util.HashSet[0]->com.food.model.neo.Pairing["first"]-

这是我的课程：

@NodeEntity
public class Ingredient {

    private Long id;
    private String name;

    @Relationship(type = "HAS_CATEGORY", direction = "OUTGOING")
    private Category category;

    @Relationship(type = "PAIRS_WITH", direction = "UNDIRECTED")
    private Set<Pairing> pairings = new HashSet<>();
}

@NodeEntity
public class Category {

    @GraphId
    private Long id;

    private String name;
}

@RelationshipEntity(type = "PAIRS_WITH")
public class Pairing {

    Long id;

    @StartNode
    private Ingredient first;
    @EndNode
    private Ingredient second;

    private String affinity;
}

这是我的控制器。

@RequestMapping(value = "/foodStory", method = RequestMethod.GET)
public ModelAndView foodStory() {
    ModelAndView model = new ModelAndView("home");

    categoryRepository.deleteAll();
    ingredientRepository.deleteAll();
    pairingRepository.deleteAll();

    //Set up the categories
    Category meat = new Category("Meat");
    Category veg = new Category("Vegetable");
    categoryRepository.save(meat);
    categoryRepository.save(veg);

    //Set up two ingredients
    Ingredient chicken = new Ingredient("Chicken");
    chicken.setCategory(meat);
    ingredientRepository.save(chicken);

    Ingredient carrot = new Ingredient("Carrot");
    carrot.setCategory(veg);
    ingredientRepository.save(carrot);


    //Pair them
    Pairing pairing = new Pairing();
    pairing.setFirst(chicken);
    pairing.setSecond(carrot);
    pairing.setAffinity("Delicious");
    pairingRepository.save(pairing);

    Ingredient carrotIngredient = session.loadByProperty(Ingredient.class, "name", "Carrot");
    List<Pairing> pairingList = (List<Pairing>) session.loadAllByProperty(Pairing.class, "second", carrotIngredient);
    //Check the data in pairingList and the result :
    //expect to happens : pairings.first != null
    //what happens : pairings.first = null
    System.out.println("Done");
return model;
}

当我尝试查看我的pairingList数据时，pairings.first返回空数据。

Spring Data Neo4j 4 - 如何正确获取多个实体的父级？

0 个答案: