Jackson控制多态的注解--JsonTypeInfo,JsonSubTypes,JsonTypeName

墨蓝 2023-08-17 15:17 109阅读 0赞

让我们看Jackson控制多态的注解：

*  @JsonTypeInfo – indicates details of what type information to include in serialization 指出序列化包含的类型信息细节
 *  @JsonSubTypes – indicates sub-types of the annotated type 指出被注解类型的子类
 *  @JsonTypeName – defines a logical type name to use for annotated class 定义被注解类使用的逻辑名称

让我们看使用这三个注解的例子--序列化/反序列化Zoo实体：

public class Zoo {
        public Animal animal;
     
        @JsonTypeInfo(
          use = JsonTypeInfo.Id.NAME, 
          include = As.PROPERTY, 
          property = "type")
        @JsonSubTypes({
            @JsonSubTypes.Type(value = Dog.class, name = "dog"),
            @JsonSubTypes.Type(value = Cat.class, name = "cat")
        })
        public static class Animal {
            public String name;
        }
     
        @JsonTypeName("dog")
        public static class Dog extends Animal {
            public double barkVolume;
        }
     
        @JsonTypeName("cat")
        public static class Cat extends Animal {
            boolean likesCream;
            public int lives;
        }
    }

当我们序列化的时候：

@Test
    public void whenSerializingPolymorphic_thenCorrect()
      throws JsonProcessingException {
        Zoo.Dog dog = new Zoo.Dog("lacy");
        Zoo zoo = new Zoo(dog);
     
        String result = new ObjectMapper()
          .writeValueAsString(zoo);
     
        assertThat(result, containsString("type"));
        assertThat(result, containsString("dog"));
    }

序列化Dog的结果：

{
        "animal": {
            "type": "dog",
            "name": "lacy",
            "barkVolume": 0
        }
    }

参考链接：

https://www.baeldung.com/jackson-annotations

转载于:https://www.cnblogs.com/windyWu/p/11243188.html