Jackson YAML序列化：如何移除多态对象的原生类型标签

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonSubTypes;
import com.fasterxml.jackson.annotation.JsonTypeInfo;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.dataformat.yaml.YAMLGenerator;
import com.fasterxml.jackson.dataformat.yaml.YAMLMapper;
import java.util.Arrays;
import java.util.List;
import static java.util.Objects.requireNonNull;

// 定义多态接口
@JsonTypeInfo(use = JsonTypeInfo.Id.NAME,
    include = JsonTypeInfo.As.EXISTING_PROPERTY,
    property = "type")
@JsonSubTypes({
    @JsonSubTypes.Type(value = Car.class, name = "car"),
    @JsonSubTypes.Type(value = Truck.class, name = "truck") })
interface Vehicle {
    String getName();
}

// Car 实现类
class Car implements Vehicle {
    String name;
    String type = "car"; // 类型标识属性

    @JsonCreator
    public Car(@JsonProperty("name") final String name) {
        this.name = requireNonNull(name);
    }

    @Override
    public String getName() {
        return name;
    }

    public String getType() {
        return type;
    }
}

// Truck 实现类
class Truck implements Vehicle {
    String name;
    String type = "truck"; // 类型标识属性

    @JsonCreator
    public Truck(@JsonProperty("name") final String name) {
        this.name = requireNonNull(name);
    }

    @Override
    public String getName() {
        return name;
    }

    public String getType() {
        return type;
    }
}

// 包含Vehicle列表的容器类
class Vehicles {
    List<Vehicle> vehicles;

    @JsonCreator
    public Vehicles(@JsonProperty("vehicles") final List<Vehicle> vehicles) {
        this.vehicles = requireNonNull(vehicles);
    }

    public List<Vehicle> getVehicles() {
        return vehicles;
    }
}

public class YamlTagRemovalDemo {
    public static void main(String[] args) throws JsonProcessingException {
        // 标准JSON ObjectMapper
        ObjectMapper JSON_MAPPER = new ObjectMapper();

        // YAML ObjectMapper，默认配置
        ObjectMapper YAML_MAPPER_DEFAULT = YAMLMapper.builder()
            .disable(YAMLGenerator.Feature.WRITE_DOC_START_MARKER) // 禁用文档开始标记
            .build();

        final Vehicles vehicles = new Vehicles(Arrays.asList(new Car("Dodge"), new Truck("Scania")));

        System.out.println("--- JSON Output ---");
        final String json = JSON_MAPPER.writerWithDefaultPrettyPrinter().writeValueAsString(vehicles);
        System.out.println(json);

        System.out.println("\n--- YAML Output (Default) ---");
        final String yamlDefault = YAML_MAPPER_DEFAULT.writerWithDefaultPrettyPrinter().writeValueAsString(vehicles);
        System.out.println(yamlDefault);
    }
}

{
  "vehicles" : [ {
    "name" : "Dodge",
    "type" : "car"
  }, {
    "name" : "Scania",
    "type" : "truck"
  } ]
}

vehicles:
- !<car>
  name: "Dodge"
  type: "car"
- !<truck>
  name: "Scania"
  type: "truck"

public class YamlTagRemovalDemo {
    public static void main(String[] args) throws JsonProcessingException {
        // ... (其他代码不变)

        // YAML ObjectMapper，禁用原生类型ID特性
        ObjectMapper YAML_MAPPER_FIXED = YAMLMapper.builder()
            .disable(YAMLGenerator.Feature.WRITE_DOC_START_MARKER) // 禁用文档开始标记
            .disable(YAMLGenerator.Feature.USE_NATIVE_TYPE_ID) // 禁用原生类型ID
            .build();

        final Vehicles vehicles = new Vehicles(Arrays.asList(new Car("Dodge"), new Truck("Scania")));

        // ... (JSON 输出不变)

        System.out.println("\n--- YAML Output (Fixed) ---");
        final String yamlFixed = YAML_MAPPER_FIXED.writerWithDefaultPrettyPrinter().writeValueAsString(vehicles);
        System.out.println(yamlFixed);
    }
}

vehicles:
- name: "Dodge"
  type: "car"
- name: "Scania"
  type: "truck"