使用GSON将Json解析为Json元素可能不同的JAVA对象 [英] Using GSON to parse Json into a JAVA Object where the Json Elements may vary

问题描述

我正在尝试使用GSON将JSON .txt文件解析为JAVA对象。 JSON文件具有以下结构：

  {
event0：{
a： abc，
b：def
}，
 
event1：{
a：ghi，
 b：jkl，
c：mno
} 
} 
  

我已将文本文件读入名为dataStr的字符串。我想使用fromJson方法将事件捕获到以下JAVA类中：

  public class Event {
 private字符串a; 
私人字符串b; 
私人字符串c; 
 
 public Event（）{} 
 
} 
  

<问题是JSON在一些元素中可能有一个额外的字段c。我想将所有事件解析为Event类对象，对于没有c字段的情况，我想在对象中使其为零或零。事先不知道哪些元素具有c字段。

具体来说，我无法弄清楚如何在一些JSON元素中处理一个额外的字段。我想做一些事情：

  Gson gson = new Gson（）; 
 ArrayList< Event> events = gson.fromJson（dataStr，Event.class）; 
  

但是我首先遇到了如何遍历Json文件中的事件，其次，如何处理一些偶尔丢失的字段到同一个Event对象中。我真的很感激一个正确的方向。谢谢大家。

我对JSON解析相当陌生，可能错过了以下答案：

使用Gson将Json转换为Java对象 p>

使用Gson将JSON映射到POJO

使用gson将json解析为java对象

将JSON解析为一个java对象

如何使用GSON将json文件解析为Java POJO类

解决方案

我不确定我是否理解你的问题的权利。根据我的理解，你正试图用一个额外的字段来转换一个json对象，而这个字段在java类中是不可用的。坦率地说，我不明白你为什么要这样做，或者如果可以开始的话。您可以通过将json转换为Map来解决这个问题。

Map map = gson.fromJson（jsonString，Map.class）;

I am trying to parse a JSON .txt file into a JAVA object using GSON. The JSON file has the following structure:

    {
        "event0" : {
        "a" : "abc",
        "b" : "def"
        },

        "event1" : {
        "a" : "ghi",
        "b" : "jkl",
        "c" : "mno"
        }
    }

I have read the text file into a String called dataStr. I want to use the fromJson method to capture the events into the following JAVA class:

public class Event {
    private String a;
    private String b;
    private String c;

    public Event() {}

}

The problem is that the JSON might have one extra field "c" in some of the elements. I want to parse all the events into Event class objects, and for the cases where there is no "c" field, I want to make it null or zero in my object. It is not known beforehand which of the elements will have the "c" field.

Specifically, I was not able to figure out how to handle one extra field in some of the JSON elements. I want to do something along the lines of:

Gson gson = new Gson();
ArrayList<Event> events = gson.fromJson(dataStr, Event.class);

But I am stuck with first, how to iterate over the events in the Json file, and secondly, how to handle some occasional missing fields into the same Event object. I would really appreciate a kick in the right direction. Thank you all.

I am fairly new to JSON parsing, and might have missed something in the following answers:

Using Gson to convert Json into Java Object

Mapping JSON into POJO using Gson

Using gson to parse json to java object

Parse JSON into a java object

How to parse a json file into a java POJO class using GSON

解决方案

I'm not sure if I understood your question right. As per my understanding, you are trying to convert a json object with an extra field which is not available in the java class. Frankly, I don't understand why you want that or if it's possible to start with. You can have a workaround by converting the json to Map.

Map map = gson.fromJson(jsonString, Map.class);

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