I suspect using linked hash map should solve your usecase. Ex.
Map mergeAndAddSchema(Map map) {
LinkedHashMap lhm = new LinkedHashMap();
lhm.put("schema", "2.0");
lhm.putAll(map);
return lhm
}
On Tue, Jul 20, 2021 at 11:33 AM Aravinda Baliga B <[email protected]> wrote:
>
> I am creating a JSON using the `Jackson JsonGenerator` approach and
> everything seems to work perfectly fine apart from a minor glitch. I would
> like to move the particular key present in the created JSON to the top of the
> JSON.
>
> I am creating a key `schema` which appears at the bottom of the JSON. I would
> like to know if there is a way to move it to the top of the JSON after
> finished creating the JSON.
>
>
> Following is the JSON that I am creating:
> ```
> public class JacksonTest {
> public static void main(String[] args) throws IOException {
> StringWriter jsonObjectWriter = new StringWriter();
> JsonGenerator jsonGenerator = new
> JsonFactory().createGenerator(jsonObjectWriter).useDefaultPrettyPrinter();
> jsonGenerator.writeStartObject();
> jsonGenerator.writeStringField("a", "Value-A");
> jsonGenerator.writeStringField("c", "Value-C");
> jsonGenerator.writeStringField("b", "Value-B");
> jsonGenerator.writeStringField("schema", "2.0");
> jsonGenerator.close();
> jsonGenerator.flush();
> System.out.println(jsonObjectWriter.toString());
> }
> }
>
> ```
>
> Following is the output I am getting:
> ```
> {
> "a" : "Value-A",
> "c" : "Value-C",
> "b" : "Value-B",
> "schema" : "2.0"
> }
> ```
>
> I would like to convert the JSON something like this:
> ```
> {
> "schema" : "2.0",
> "a" : "Value-A",
> "c" : "Value-C",
> "b" : "Value-B"
> }
> ```
>
> I would like to fetch the `schema` from my created JSON and add it to the top
> of the JSON.
>
> `Please Note:`
> 1. I am aware the JSON order does not matter but I am doing this for better
> readability purposes. If there is a way then it would be really useful for
> the reader to understand the JSON better.
>
> 2. I am aware that I can create the `schema` at first in this code but this
> is just a sample application that I have provided for ease of understanding.
> In my real application, I have a `Map` that is populated dynamically
> throughout the execution and I am adding it at the end of the JSON creation.
> If I add at the first then I will miss out on a few of the values which are
> populated after creation so I am adding at the end but I want this to appear
> at the top of the JSON so trying to move to the top.
>
> 3. I want to know if there is a direct way to do it rather than looping over
> the JSON, as my created JSON in the real application can be pretty large.
>
> I would really appreciate it if there was a way to do it or is there any
> workaround for this.
>
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// Mantas
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