java - Jackson JSON强制反序列化为对象

Question

我有一个带委托(delegate)的类(class)设置

public class MyClass implements List<Integer> {

    public String name;

    public List<Integer> target; // this is the delegation target
    // more fields

    @Override
    public Integer get(int index) {
        return target.get(index);
    }
    // all other method in target interface is delegated 
}

我得到了一个如下所示的 JSON:

{"target": [1, 2, 3] , "name":"foo"}

jackson 抛出了这个:

Exception in thread "main" com.fasterxml.jackson.databind.JsonMappingException: Can not deserialize instance of com.foo.MyClass out of START_OBJECT token
 at [Source: java.io.StringReader@156e5f3e; line: 1, column: 1]
    at com.fasterxml.jackson.databind.JsonMappingException.from(JsonMappingException.java:164)
    at com.fasterxml.jackson.databind.DeserializationContext.mappingException(DeserializationContext.java:691)
    at com.fasterxml.jackson.databind.DeserializationContext.mappingException(DeserializationContext.java:685)
    at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.handleNonArray(CollectionDeserializer.java:256)
    at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:214)
    at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:204)
    at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:23)
    at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:2986)
    at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2091)

我推测 Jackson 认为 MyClass 是一个列表，所以不知道如何处理 {}因为[]预计

我通过制作 MyClass 证实了我的猜测不实现List<Integer> :

public class MyClass { /*same stuff*/}

一切正常。但是我需要 MyClass 来实现 List<Integer> ....

我可以使用模块中的注释或配置来解决这个问题吗？

Answer 1

我在阅读 this article 时偶然发现了我的答案, 基本上，我需要用

注释我的类

@JsonFormat(shape = Shape.OBJECT)