具有包装结构的JSON和具有扁平结构的pojo之间的转换 [英] Conversion between JSON with wrapped structure and pojo with flattended structure

问题描述

我有一个JSON结构，其中包含了我的POJO中没有的包装级别.像这样:

I have a JSON structure that incorporates a wrapping level that I don't have in my POJOs. Like so:

JSON:

{
    "category1": {
        "cat1Prop1": "c1p1",
        "cat1Prop2": "c1p2",
        "cat1Prop3": "c1p3"
    },
    "category2": {
        "cat2Prop1": "c2p1",
        "cat2Prop2": "c2p2"
    },
    "category3": {
        "cat3Prop1": "c3p1",
        "cat3Prop2": "c3p2",
        "cat3Prop3": "c3p3"
    },
    "category4": {
        "cat4Prop1": "c4p1"
    }
}

POJO:

public class MyPojo {

    private String cat1Prop1;
    private String cat1Prop2;
    private String cat1Prop3;

    private String cat2Prop1;
    private String cat2Prop2;

    private String cat3Prop1;
    private String cat3Prop2;
    private String cat3Prop3;

    private String cat4Prop1;


    // Getters / setters, etc...
}

如您所见，JSON具有类别"级别(出于各种原因，我不想在Pojo中使用它).

As you can see, the JSON have a "category" level (that for different reasons I don't want to have in my Pojo).

我正在寻找一种使用Jackson进行序列化/反序列化的方法，以便以一种流畅的方式进行处理.

I'm looking for a way to use Jackson for serializaion/deserialization to handle this in a smooth way.

我知道Jackson的 @ JsonUnwrapped 注释则相反.我还知道，有一个功能请求，它要求"@JsonWrapped" 批注我认为这可以解决我的问题.

I'm aware that Jackson has a @JsonUnwrapped annotation that kind of handles the opposite. I'm also aware that there is a feature request for a "@JsonWrapped" annotation that I think would solve my case.

非常感谢您提供的任何输入或帮助，因为我一直在四处寻找.另外，关于如何使用其他任何库(例如gson，flexjson等)完成此操作的任何建议也很有趣.

Thankful for any input or help regarding this, as I have been looking around quite a bit. Also, any suggestions on how this could be accomplished using any other library (like gson, flexjson, etc) is also interesting.

推荐答案

您可以尝试使用以下算法:

You can try with this algorithm:

1. 将JSON读取为Map.
2. 平面地图
3. 使用ObjectMapper将Map转换为POJO.

实施可能看起来像这样:

Implementation could looks like this:

ObjectMapper mapper = new ObjectMapper();

Map<String, Map<String, String>> map = mapper.readValue(new File("X:/test.json"), Map.class);
Map<String, String> result = new HashMap<String, String>();
for (Entry<String, Map<String, String>> entry : map.entrySet()) {
    result.putAll(entry.getValue());
}

System.out.println(mapper.convertValue(result, MyPojo.class));

这篇关于具有包装结构的JSON和具有扁平结构的pojo之间的转换的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！