英文:
Is it possible to specify the order of ObjectNode properties without using annotations?
问题
Jackson允许用户使用@JsonProperty(index = ?)注解为ObjectNode属性指定显式序列化顺序。这意味着，对于属性a，b，c，我可以指示Jackson按照以下顺序进行序列化：b，a，c。我可以控制确切的序列化顺序。
是否可以在不使用注解的情况下实现相同的效果？
我不想进行字母排序，我想指定显式排序顺序。
英文:
Jackson allows users to specify an explicit serialization order for ObjectNode properties using the @JsonProperty(index = ?) annotation. Meaning, given properties a, b, c I can instruct Jackson to serialize them in the following order: b, a, c. I control the exact serialization order.
Is it possible to achieve the same without the use of annotations?
I do not want alphabetic sorting. I want to specify an explicit sorting order.
答案1
得分: 0
你可以扩展 com.fasterxml.jackson.databind.introspect.JacksonAnnotationIntrospector 类，并通过重写 findSerializationPropertyOrder 方法为任何你想要的类提供顺序。
import com.fasterxml.jackson.databind.SerializationFeature;import com.fasterxml.jackson.databind.introspect.AnnotatedClass;import com.fasterxml.jackson.databind.introspect.JacksonAnnotationIntrospector;import com.fasterxml.jackson.databind.json.JsonMapper;import lombok.Data;public class JacksonAnnotationIntrospectorApp {private final static JsonMapper JSON_MAPPER = JsonMapper.builder().enable(SerializationFeature.INDENT_OUTPUT).annotationIntrospector(new DynamicOrderJacksonAnnotationIntrospector()).build();public static void main(String[] args) throws Exception {var pojo = new DynamicOrderPojo();pojo.setA("A");pojo.setB(1);pojo.setC(3.33);JSON_MAPPER.writeValue(System.out, pojo);}}class DynamicOrderJacksonAnnotationIntrospector extends JacksonAnnotationIntrospector {@Overridepublic String[] findSerializationPropertyOrder(AnnotatedClass ac) {if (ac.getRawType() == DynamicOrderPojo.class) {return new String[]{"b", "a", "c"};}return super.findSerializationPropertyOrder(ac);}}@Dataclass DynamicOrderPojo {private String a;private Integer b;private Double c;}
以上代码会输出：
{"b" : 1,"a" : "A","c" : 3.33}
也可以参考：
英文:
You can extend com.fasterxml.jackson.databind.introspect.JacksonAnnotationIntrospector class and provide your order for any class you want by overriding findSerializationPropertyOrder method.
import com.fasterxml.jackson.databind.SerializationFeature;import com.fasterxml.jackson.databind.introspect.AnnotatedClass;import com.fasterxml.jackson.databind.introspect.JacksonAnnotationIntrospector;import com.fasterxml.jackson.databind.json.JsonMapper;import lombok.Data;public class JacksonAnnotationIntrospectorApp {private final static JsonMapper JSON_MAPPER = JsonMapper.builder().enable(SerializationFeature.INDENT_OUTPUT).annotationIntrospector(new DynamicOrderJacksonAnnotationIntrospector()).build();public static void main(String[] args) throws Exception {var pojo = new DynamicOrderPojo();pojo.setA("A");pojo.setB(1);pojo.setC(3.33);JSON_MAPPER.writeValue(System.out, pojo);}}class DynamicOrderJacksonAnnotationIntrospector extends JacksonAnnotationIntrospector {@Overridepublic String[] findSerializationPropertyOrder(AnnotatedClass ac) {if (ac.getRawType() == DynamicOrderPojo.class) {return new String[]{"b", "a", "c"};}return super.findSerializationPropertyOrder(ac);}}@Dataclass DynamicOrderPojo {private String a;private Integer b;private Double c;}
Above code prints:
{"b" : 1,"a" : "A","c" : 3.33}
See also:
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