我得到了一个接口+ 2个具体的子类，都为Jackson做了注解。这两个子类可以独立工作。这两个子类由字段（K/V对）的 name 区分，而不是某个K/V对的 value。

• 因此，我不能使用任何正常的Jackson PTH功能。或者我可以吗？请让我知道**

我希望他们序列化w/o任何 Package 或注入字段。
我要使用的例子（full MCVE gist is here）是一个BookId接口，其中具体的实现者是ISBN和ASIN，每个都有一个字段。BookId s的示例数组如下所示：

{ "ids": [
    { "isbn" : "978-0-596-52306-0" },
    { "asin" : "B07QKFQ7QJ" }
]}

所以ISBN和ASIN非常简单，这里是ISBN（ASIN类似于不同的验证器方法）：

public static class ISBN implements BookId {
    final String isbn;

    @JsonCreator
    public ISBN(@JsonProperty("isbn") String isbn) {
        if (!valid(isbn)) throw new IllegalArgumentException("bad isbn syntax");
        this.isbn = isbn;
    }

    boolean valid(String isbn) { return isbn != null && !isbn.isBlank() /* && checksum ok ... */; }
}

因此，尝试我认为是一种 * 正确 * 的方法-简单地区分这两种情况，然后适当地调用对象Map器-看起来像这样：

@JsonDeserialize(using = BookId.DeserializerDirectViaJackson.class)
public interface BookId {

    class DeserializerDirectViaJackson extends StdDeserializer<BookId> {
        public DeserializerDirectViaJackson() { this(null); }
        public DeserializerDirectViaJackson(final Class<?> vc) { super(vc); }

        @Override
        public BookId deserialize(JsonParser jsonParser, DeserializationContext deserializationContext) throws IOException {
            final var om = (ObjectMapper) jsonParser.getCodec();
            final var node = (JsonNode) om.readTree(jsonParser);
            if (!node.isObject()) throw new IllegalStateException("expected JSON object");
            if (node.has("isbn")) return om.treeToValue(node, ISBN.class);
            if (node.has("asin")) return om.treeToValue(node, ASIN.class);
            throw new IllegalStateException("expected 'isbn' or 'asin' field");
        }
    }
...

其中的关键行是：

if (node.has("isbn")) return om.treeToValue(node, ISBN.class);
            if (node.has("asin")) return om.treeToValue(node, ASIN.class);

在这里，我在TreeValue中查找区分键，然后调用ObjectMapper.treeToValue(node, <concreteclass>.class)来正确解析它。
但这会导致无限递归，如图所示（调用堆栈的顶部）：

> Task :cli:JacksonInterfaceCustomDeserializerMCVE.main() FAILED
Exception in thread "main" java.lang.StackOverflowError
    at java.base/java.util.LinkedHashMap$LinkedEntryIterator.next(LinkedHashMap.java:788)
    at java.base/java.util.LinkedHashMap$LinkedEntryIterator.next(LinkedHashMap.java:786)
    at com.fasterxml.jackson.databind.node.NodeCursor$ObjectCursor.nextToken(NodeCursor.java:214)
    at com.fasterxml.jackson.databind.node.TreeTraversingParser.nextToken(TreeTraversingParser.java:108)
    at com.fasterxml.jackson.core.JsonParser.nextFieldName(JsonParser.java:1091)
    at com.fasterxml.jackson.databind.deser.std.BaseNodeDeserializer._deserializeContainerNoRecursion(JsonNodeDeserializer.java:536)
    at com.fasterxml.jackson.databind.deser.std.JsonNodeDeserializer.deserialize(JsonNodeDeserializer.java:100)
    at com.fasterxml.jackson.databind.deser.std.JsonNodeDeserializer.deserialize(JsonNodeDeserializer.java:25)
    at com.fasterxml.jackson.databind.deser.DefaultDeserializationContext.readRootValue(DefaultDeserializationContext.java:323)
    at com.fasterxml.jackson.databind.ObjectMapper._readValue(ObjectMapper.java:4801)
    at com.fasterxml.jackson.databind.ObjectMapper.readTree(ObjectMapper.java:3084)
    at com.bakinsbits.bookcatalog.JacksonInterfaceCustomDeserializerMCVE$BookId$DeserializerDirectViaJackson.deserialize(JacksonInterfaceCustomDeserializerMCVE.java:58)
    at com.bakinsbits.bookcatalog.JacksonInterfaceCustomDeserializerMCVE$BookId$DeserializerDirectViaJackson.deserialize(JacksonInterfaceCustomDeserializerMCVE.java:51)
    at com.fasterxml.jackson.databind.deser.DefaultDeserializationContext.readRootValue(DefaultDeserializationContext.java:323)
    at com.fasterxml.jackson.databind.ObjectMapper._readValue(ObjectMapper.java:4801)
    at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2974)
    at com.fasterxml.jackson.databind.ObjectMapper.treeToValue(ObjectMapper.java:3438)
    at com.bakinsbits.bookcatalog.JacksonInterfaceCustomDeserializerMCVE$BookId$DeserializerDirectViaJackson.deserialize(JacksonInterfaceCustomDeserializerMCVE.java:60)
    at com.bakinsbits.bookcatalog.JacksonInterfaceCustomDeserializerMCVE$BookId$DeserializerDirectViaJackson.deserialize(JacksonInterfaceCustomDeserializerMCVE.java:51)
    at com.fasterxml.jackson.databind.deser.DefaultDeserializationContext.readRootValue(DefaultDeserializationContext.java:323)
    at com.fasterxml.jackson.databind.ObjectMapper._readValue(ObjectMapper.java:4801)
    at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2974)

等等等等。

**所以，问题是：**为什么它会这样做，更重要的是-我如何使它工作？

为了比较（并显示我做了工作），下面的解析器 * 确实 * 工作，但有（主要）缺点，我基本上必须自己解析和验证具体的子类。对于这个玩具示例是可行的，但对于真实的用例就不那么可行了。

class DeserializerHomegrown extends StdDeserializer<BookId> {
        public DeserializerHomegrown() { this(null); }
        public DeserializerHomegrown(final Class<?> vc) { super(vc); }

        @Override
        public BookId deserialize(JsonParser jsonParser, DeserializationContext deserializationContext) throws IOException {
            final var om = (ObjectMapper) jsonParser.getCodec();
            final var node = (JsonNode) om.readTree(jsonParser);
            if (!node.isObject()) throw new IllegalStateException("expected JSON object");
            if (node.has("isbn")) return new ISBN(getValueNode(node, "isbn"));
            if (node.has("asin")) return new ASIN(getValueNode(node, "asin"));
            throw new IllegalStateException("expected 'isbn' or 'asin' field");
        }

        String getValueNode(JsonNode node, String fieldName) {
            final var field = node.get(fieldName);
            if (field == null) return null;
            if (!field.isValueNode()) throw new IllegalStateException("%s field is not JSON value".formatted(fieldName));
            return field.asText();
        }
    }