无法在 Spring Boot 中以多态方式反序列化 mongo db 集合

Question

我有一个名为“items”的 mongo 系列，其中包含珠宝。 在集合的每个文档中，我都有一个鉴别器属性“类别” - 我使用杰克逊多态注释将文档反序列化为特殊的类，如 Pendatnt、Ring 等。 我正在使用抽象类和一些实现来获取项目。 我收到一条错误消息： “无法实例化……使用构造函数保护的珠宝……珠宝” Jewelery.java 是我的父抽象类， 这意味着框架尝试使用抽象类而不是使用我的实现。 看来杰克逊“@JsonSubTypes”注释被完全忽略了，我不明白为什么[所有这些设置过去都可以100%正常工作，但最近我发现我不再这样做了]

这是抽象类的示例，后面是 5 个实现之一。

/***************Jewelery.java****************************/
@JsonTypeInfo(
        use = JsonTypeInfo.Id.NAME,
        include = JsonTypeInfo.As.EXISTING_PROPERTY,
        property = "category",
        visible = true
)
@JsonSubTypes({
        @JsonSubTypes.Type(value = Bracelet.class, name = "BRACELETS"),
        @JsonSubTypes.Type(value = Earring.class, name = "EARRINGS"),
        @JsonSubTypes.Type(value = Pendant.class, name = "PENDANTS"),
        @JsonSubTypes.Type(value = Ring.class, name = "RINGS"),
        @JsonSubTypes.Type(value = Set.class, name = "SETS")
})
@Document(collection = "items")
@Getter
@Setter
public abstract class Jewelery implements Sellable {

    @Id
    private  String _id;
    private  String catId;`your text`
    private  String name;

    private Category category; // this is the discriminator property!

    private Integer importance;
    private  Integer price;
    private  Integer inStockQuantity;

    private  Boolean isDraft;
    private  Boolean isOnSale;

    private  Integer rating;
    private  Integer priority; 

    protected  String[] images; // single item images

    //single item properties;
    private  String[] materials;
    private Size size;

    private String _class;

    protected Jewelery(String _id, String catId, String name, Category category, Integer importance,Integer price, Integer inStockQuantity, Boolean isDraft, Boolean isOnSale, Integer rating, Integer priority, String[] images, String[] materials, Size size, String _class) {
        this._id = _id;
        this.catId = catId;
        this.name = name;
        this.category = category;
        this.importance = importance;
        this.price = price;
        this.inStockQuantity = inStockQuantity;
        this.isDraft = isDraft;
        this.isOnSale = isOnSale;
        this.rating = rating;
        this.priority = priority;
        this.images = images;
        this.materials = materials;
        this.size = size;
        this._class = _class;
    }
}

/*************Bracelet.java****************/
@TypeAlias("Bracelet")
public class Bracelet extends Jewelery implements Sellable {

    public Bracelet(String _id, String catId, String name, Category category, Integer importance, Integer price, Integer inStockQuantity, Boolean isDraft, Boolean isOnSale, Integer rating, Integer priority, String[] images, String[] materials, Size size, String _class) {
        super(_id, catId, name, category, importance, price, inStockQuantity, isDraft, isOnSale, rating, priority, images, materials, size, _class);
    }

    @Override
    public String[] getImages() {
        return images;
    }

    @Override
    public void setImages(String[] images) {
        this.images  = images;
    }
}

/*************my repository class**********************************/
@Repository("items")
public interface JeweleryRepository extends MongoRepository<Jewelery, String> {
}

/*****my service call***********************************/
public List<Jewelery> getItems(String sortBy) {
  return jewelryRepo.findAll();
}  

我尝试从父抽象类中删除

@Document(collection = "items")

并将此注释放在所有实现上。它不起作用，因为 mongo 无法识别集合名称，并且默认情况下会尝试从不存在的“珠宝”集合中获取项目，从而导致空数组响应。

Answer 1

您可以使用转换器和映射配置来解决。

定义自己的Writing Converter和Reading Converter，将它们注册到AbstractMongoClientConfiguration中

相关文档：converter、AbstractMongoClientConfiguration