让Jackson将单个JSON对象解释为具有一个元素的数组 [英] Make Jackson interpret single JSON object as array with one element

问题描述

有没有办法让Jackson将单个JSON对象解释为具有一个元素的数组，反之亦然？

Is there a way to make Jackson interpret single JSON object as an array with one element and vice versa?

示例，我有两种略有不同的JSON格式，我需要映射到同一个Java对象：

Example, I have 2 slightly different formats of JSON, I need both to map to same Java object:

格式 A （带有一个元素的JSON数组）：

Format A (JSON array with one element):

points : [ {
    date : 2013-05-11
    value : 123
}]

格式 B （JSON对象，是的，我知道它看起来错了但它就是我的意思给定）：

Format B (JSON object, yes I know it looks "wrong" but it's what I'm given):

points : {
    date : 2013-05-11
    value : 123
}

目标Java对象，以上两者都应转换为：

Target Java object that both of the above should convert to:

//Data.java 
public List<Point> points;
//other members omitted

//Point.java
class Point {
    public String date;
    public int value;
}

目前，只有 A 会正确解析数据。我想避免直接篡改JSON本身。杰克逊是否有一些配置我可以篡改以使其接受 B ？

Currently, only A will parse properly to Data. I want avoid directly tampering with the JSON itself. Is there some configuration in Jackson I can tamper with in order to make it accept B ?

推荐答案

尝试使用 DeserializationFeature。 ACCEPT_SINGLE_VALUE_AS_ARRAY - 它应该适合你。

Try with DeserializationFeature.ACCEPT_SINGLE_VALUE_AS_ARRAY - it should work for you.

示例：

final String json = "{\"date\" : \"2013-05-11\",\"value\" : 123}";

final ObjectMapper mapper = new ObjectMapper()
        .enable(DeserializationFeature.ACCEPT_SINGLE_VALUE_AS_ARRAY);
final List<Point> points = mapper.readValue(json,
        new TypeReference<List<Point>>() {
        });
System.out.println(points);

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