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当value1的java类依赖于value2时,如何使用jackson反序列化JSON

deserialization jackson serialization json java

Egor Stepanov · 技术社区 · 5 年前

我有一个JSON字符串:

{
  "entities": [
    {
      "type": "fio",
      "value": {
        "firstName": "first",
        "lastName": "last"
      }
    },

    {
      "type": "geo",
      "value": {
        "country": "the country",
        "city": "the city"
      }
    },

    {
      "type": "number",
      "value": 100
    },

    {
      "type": "number",
      "value": 3.14
    }
  ]
}

这是一些实体的列表,它们有参数类型价值取决于类型 ,param 价值具有特定的代表性。

例如:

类型是菲奥然后是包含两个字段的复杂对象: 和姓氏
如果类型是 地理位置 然后价值是包含字段的复杂对象: , 城市 , ...
是数字然后价值

我创建了一个abstract类 实体值 我使用了jackson注释:

@JsonTypeInfo(
  use = JsonTypeInfo.Id.NAME, 
  include = JsonTypeInfo.As.PROPERTY, 
  property = "type")
@JsonSubTypes({ 
  @Type(value = GeoEntityValue.class, name = "geo"), 
  @Type(value = FioEntityValue.class, name = "fio"),
  ... 
})
public class Entity {

    private final EntityType type;
    private final EntityValue value;

    ... constructor and getters ...
}

菲奥或但我和一个数字它像一个复杂对象一样进行序列化和反序列化,而不像前面提到的示例。

您能帮我管理jackson注释或重新组织类层次结构以使序列化和反序列化工作正常吗?

谢谢

1 回复 | 直到 5 年前

Prabhakar D 5 年前

  @JsonTypeInfo(
    use = JsonTypeInfo.Id.NAME,
    include = As.PROPERTY,
    property = "type")
@JsonSubTypes(value = {
    @Type(value = GeoEntity.class, name = "geo"),
    @Type(value = FioEntity.class, name = "fio"),
    @Type(value = Number.class, name ="number")
})
public abstract class Entity {

  public void setType(String type) {
    this.type = type;
  }

  private String type;

  @Override
  public String toString(){
    return ToStringBuilder.reflectionToString(this);
  }

}

FioEntity类(类似于创建GeoEntity的方法)

    public class FioEntity extends Entity {

      public FioEntityValue getValue() {
        return value;
      }

      public void setValue(FioEntityValue value) {
        this.value = value;
      }

      private FioEntityValue value;


    public class FioEntityValue extends  EntityValue{

      private String firstName;

      private String lastName;


      public String getLastName() {
        return lastName;
      }

      public void setLastName(String lastName) {
        this.lastName = lastName;
      }

      public String getFirstName() {
        return firstName;
      }

      public void setFirstName(String firstName) {
        this.firstName = firstName;
      }
    }
   }

编号类别:

public class Number extends Entity {

  private Double value;

  public Double getValue() {
    return value;
  }

  public void setValue(Double value) {
    this.value = value;
  }

}

测试等级:

public class Test {

  public static void main(String[] args) throws IOException {


    ObjectMapper mapper = new ObjectMapper();
    mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);

    String content = "{\n"
        + "  \"entities\": [\n"
        + "    {\n"
        + "      \"type\": \"fio\",\n"
        + "      \"value\": {\n"
        + "        \"firstName\": \"first\",\n"
        + "        \"lastName\": \"last\"\n"
        + "      }\n"
        + "    },\n"
        + "\n"
        + "    {\n"
        + "      \"type\": \"geo\",\n"
        + "      \"value\": {\n"
        + "        \"country\": \"the country\",\n"
        + "        \"city\": \"the city\"\n"
        + "      }\n"
        + "    },\n"
        + "\n"
        + "    {\n"
        + "      \"type\": \"number\",\n"
        + "      \"value\": 100\n"
        + "    },\n"
        + "\n"
        + "    {\n"
        + "      \"type\": \"number\",\n"
        + "      \"value\": 3.14\n"
        + "    }\n"
        + "  ]\n"
        + "}";

    Entities test = mapper.readValue(content, Entities.class);

    System.out.println(mapper.writeValueAsString(test));


  }

}

输出:

 {"entities":[{"type":"fio","value":{"firstName":"first","lastName":"last"}},{"type":"geo","value":{"city":"the city","country":"the country"}},{"type":"number","value":100.0},{"type":"number","value":3.14}]}