我需要序列化包含NaN数字的Double字段，但Jackson总是试图将其写成String，例如。"value": "Nan"，怎么改成"value": Nan？
下面是复制的代码：

import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.json.JsonReadFeature;
import com.fasterxml.jackson.databind.ObjectMapper;

public class Test {
    public String name;
    public int age;
    private int favoriteNumber;
    private Double value = Double.NaN;

    public Test(String name, int age, int favoriteNumber) {
        this.name = name;
        this.age = age;
        this.favoriteNumber = favoriteNumber;
    }

    @JsonProperty
    public String getFavoriteNumber() {
        return String.valueOf(favoriteNumber);
    }

    @JsonProperty
    public Double getValue() {
        return this.value;
    }

    public static void main(String... args) throws Exception {
        Test p = new Test("Joe", 25, 123);
        ObjectMapper mapper = new ObjectMapper();
        mapper.enable(JsonReadFeature.ALLOW_NON_NUMERIC_NUMBERS.mappedFeature());
        mapper.configure(JsonParser.Feature.ALLOW_NON_NUMERIC_NUMBERS, true);
        System.out.println(mapper.writeValueAsString(p));
        // {"name":"Joe","age":25,"favoriteNumber":"123","value":"NaN"}
    }
}