Question

试图实现这个

@RequestMapping
public String helloWorld(@RequestBody Parent interface){
    // do something with interface

}

其中Parent是一个接口，而Child1和Child2是实现。

因为这些是第三方库.class文件，所以我无法使用@JsonTypeInfo

这种情况有解决办法吗？

Answer 1

是的，您可以使用Jackson Mixin为第三方/不可接触的课程提供杰克逊注释。

https://github.com/FasterXML/jackson-docs/wiki/JacksonMixInAnnotations

这个例子相当陈旧，从这里开始提供，但从上次实现MixIn时看起来仍然正确，

http://programmerbruce.blogspot.co.uk/2011/05/deserialize-json-with-jackson-into.html

上面的例子5，

{     "animals":
    [
       {"type":"dog","name":"Spike","breed":"mutt",        
       "leash_color":"red"},
       {"type":"cat","name":"Fluffy",
           "favorite_toy":"spider ring"}
     ]
   }


import java.io.File;
import java.util.Collection;

import org.codehaus.jackson.annotate.JsonSubTypes;
import org.codehaus.jackson.annotate.JsonTypeInfo;
import org.codehaus.jackson.annotate.JsonSubTypes.Type;
import org.codehaus.jackson.map.ObjectMapper;

public class Foo
{
  public static void main(String[] args) throws Exception
  {
    ObjectMapper mapper = new ObjectMapper();
    mapper.setPropertyNamingStrategy(
        new CamelCaseNamingStrategy());
    mapper.getDeserializationConfig().addMixInAnnotations(
        Animal.class, PolymorphicAnimalMixIn.class);
    mapper.getSerializationConfig().addMixInAnnotations(
        Animal.class, PolymorphicAnimalMixIn.class);
    Zoo zoo = 
      mapper.readValue(new File("input_5.json"), Zoo.class);
    System.out.println(mapper.writeValueAsString(zoo));
  }
}

class Zoo
{
  public Collection<Animal> animals;
}

@JsonTypeInfo(
    use = JsonTypeInfo.Id.NAME,
    include = JsonTypeInfo.As.PROPERTY,
    property = "type")
@JsonSubTypes({
    @Type(value = Cat.class, name = "cat"),
    @Type(value = Dog.class, name = "dog") })
abstract class PolymorphicAnimalMixIn
{

}

abstract class Animal
{
  public String name;
}

class Dog extends Animal
{
  public String breed;
  public String leashColor;
}

class Cat extends Animal
{
  public String favoriteToy;
}

您可以使用Jackson2ObjectMapperBuilder或Jackson2ObjectMapperFactoryBean在Spring Boot中注册MixIn。

可以在此处找到上述Spring Boot世界中的上述工作示例，其中测试验证了Cat / Dog的成功POST，例如：父类的具体实现。

https://github.com/Flaw101/springbootmixin

Spring @RequestBody for subclass。 @JsonTypeInfo的替代？

1 个答案: