您必须使用@JsonTypeInfo和@JsonSubtypes注解Book DTO，以便Jackson/Spring知道如何解组它。
下面是一个例子：

@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, property = "type", visible = true)
@JsonSubTypes({
        @JsonSubTypes.Type(value = AntiqueBook.class, name = "ANTIQUE"),
        @JsonSubTypes.Type(value = ScienceBook.class, name = "SCIENCE")
})
public class Book {

    private final String isbn;

    public Book(String isbn) {
        this.isbn = isbn;
    }

    public String getIsbn() {
        return isbn;
    }
}

public class AntiqueBook extends Book{

    private final String year;

    public AntiqueBook(String isbn, String year) {
        super(isbn);
        this.year = year;
    }

    public String getYear() {
        return year;
    }
}

public class ScienceBook extends Book{

    private final String author;

    public ScienceBook(String isbn, String author) {
        super(isbn);
        this.author = author;
    }

    public String getAuthor() {
        return author;
    }
}

@RestController
public class BookController {

    @PostMapping("/books")
    Book newBook(@RequestBody Book book) {
        return book;
    }

}

$>curl -X POST localhost:8080/books -d '{"isbn":"AAAA", "year":"2020", "type":"ANTIQUE"}' -H "Content-Type: application/json"

{"type":"ANTIQUE","isbn":"AAAA","year":"2020"}

$> curl -X POST localhost:8080/books -d '{"isbn":"AAAA", "author":"John", "type":"SCIENCE"}' -H "Content-Type: application/json"

{"type":"SCIENCE","isbn":"AAAA","author":"John"}