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Java - Access JSON Element (llegalFormatConversionException: d !=java.lang.String)

I am trying to learn JAVA and build a plugin for Minecraft; I have been successfully able to get the JSON data from my api endpoint however, the issue I am facing right now is an llegalFormatConversionException: d !=java.lang.String which means that the format I am trying to make into string isn't equal to the type of string that it's looking for.
I am trying to access a JSON element from my endpoint called condition
{
"todaysdate": "2021-02-12",
"temperature": 25,
"description": [
"Overcast"
],
"condition": 122,
}
Coming from C#; I know there's a website called json2sharp where you can create a root class for the JSON. I'm not sure how it would be applied in Java but currently, my code looks like this.
private String fetchWeather() throws IOException, InvalidConfigurationException {
// Download
final URL url = new URL(API);
final URLConnection request = url.openConnection();
// Set HEADER
request.setRequestProperty("x-api-key", plugin.apiKey);
request.setConnectTimeout(5000);
request.setReadTimeout(5000);
request.connect();
// Convert to a JSON object to print data
JsonParser jp = new JsonParser(); //from gson
JsonElement root = jp.parse(new InputStreamReader((InputStream) request.getContent())); //Convert the input stream to a json element
JsonObject rootobj = root.getAsJsonObject();
//JsonElement code = rootobj.get("condition");
String condition_code = rootobj.get("condition").toString();
plugin.getLogger().fine(String.format(
"[%s] Weather is %d",
world.getName(), condition_code
));
return condition_code;
}
If I call
private JsonObject fetchWeather() throws IOException, InvalidConfigurationException {
// Download
final URL url = new URL(API);
final URLConnection request = url.openConnection();
// Set HEADER
request.setRequestProperty("x-api-key", plugin.apiKey);
request.setConnectTimeout(5000);
request.setReadTimeout(5000);
request.connect();
// Convert to a JSON object to print data
JsonParser jp = new JsonParser(); //from gson
JsonElement root = jp.parse(new InputStreamReader((InputStream) request.getContent())); //Convert the input stream to a json element
JsonObject rootobj = root.getAsJsonObject();
return rootobj;
}
state = fetchWeather();
plugin.getLogger().warning(state.toString());
I do get the actual JSON with all of the elements so I know the URL and accessing it is completely working, but I get an llegalexception for format if I try to call and print with logger the condition code.
So, if I change the return type in fetchWeather() to be the root json object and then try to print it with the state variable above it works; but if I try to return the condition json element and print it it gives me an iilegal exception.
Now before I posted this question I did read some other questions people had but I couldn't get a working solution from their suggested answers. So, I am hoping someone can point me out on what I'm doing wrong because I know I'm messing up somewhere with the variable format.
Thanks.
Line 37: state = fetchWeather();
Line 103:
plugin.getLogger().fine(String.format(
"[%s] Weather is %d",
world.getName(), bId
));

condition_code variable is String. You should use the %s format specifier.

Parsing unquoted JSON keys using org.json.simple in Java

I have a JSON stored in a string.
String data = "{code: '0', distCode: '123'}";
I need to get the values of code, distCode. But when I try to parse it as below
JSONParser parser = new JSONParser();
JSONObject Details = (JSONObject) parser.parse(data);
Unexpected character (c) at position 2 exception is thrown.
I am sure it is because of unquoted keys in the string. How to parse the string into an JSON object using org.json.simple library?

Could not find way to achieve it using org.json.simple library. Finally done it using jackson libraries.
String data = "{code: '0', distCode: '123'}";
ObjectMapper mapper = new ObjectMapper();
mapper.configure(JsonParser.Feature.ALLOW_SINGLE_QUOTES, true);
mapper.configure(JsonParser.Feature.ALLOW_UNQUOTED_FIELD_NAMES, true);
Map<String, String> Shop_Details = mapper.readValue(data), Map.class);

Avro: SpecificDatumReader/Writer vs ReflectDatumReader/Writer

I have a byte[] representation of Avro payload and the schema which is used to encode/decode this payload. There are a few ways to convert this payload to a SpecificRecord, using ReflectDatumReader/Writer and SpecificDatumReader/Writer.
We get an error when we decode using SpecificDatumReader and try to encode a SpecificRecord returned using ReflectDatumReader.
Below is the sample code. Using SpecificDatumReader to get a SpecificRecord (Testing) then using ReflectDatumWriter to attempt to encode it into a byte[], which fails. Finally using a SpecificDatumReader to re-decode it.
DatumWriter<Testing> refWriter = new ReflectDatumWriter<>(expectedSchema);
DatumReader<Testing> specReader = new SpecificDatumReader<>(expectedSchema);
// Use SpecificDatumReader to decode to a SpecificRecord
Testing r1 = specReader.read(null, DecoderFactory.get().binaryDecoder(expectedBytePayload, null));
// Use ReflectDatumWriter to write SpecificRecord encode as byte[].
// Note: this step fails
ByteArrayOutputStream outStream = new ByteArrayOutputStream();
refWriter.write(r1, EncoderFactory.get().binaryEncoder(outStream, null));
// Use SpecificDatumReader to decode to a SpecificRecord
Testing r2 = specReader.read(null, DecoderFactory.get().binaryDecoder(outStream.toByteArray(), null));
Error Message:
java.io.EOFException
at org.apache.avro.io.BinaryDecoder.ensureBounds(BinaryDecoder.java:473)
at org.apache.avro.io.BinaryDecoder.readDouble(BinaryDecoder.java:243)
at org.apache.avro.io.ResolvingDecoder.readDouble(ResolvingDecoder.java:190)
at org.apache.avro.generic.GenericDatumReader.readWithoutConversion(GenericDatumReader.java:185)
at org.apache.avro.generic.GenericDatumReader.read(GenericDatumReader.java:152)
at org.apache.avro.generic.GenericDatumReader.readField(GenericDatumReader.java:240)
at org.apache.avro.generic.GenericDatumReader.readRecord(GenericDatumReader.java:230)
at org.apache.avro.generic.GenericDatumReader.readWithoutConversion(GenericDatumReader.java:174)
at org.apache.avro.generic.GenericDatumReader.read(GenericDatumReader.java:152)
at org.apache.avro.generic.GenericDatumReader.read(GenericDatumReader.java:144)
Why aren't they interchangeable?
When do we use one over another?

Java JSON - gson - appending new data, malformed JSON

I am using Gson to write to and read from a file.
each time a user is created, I append a line which shows Username and ID.
I do this with the following (UserAccount being my pojo class, br is my buffered reader)::
UserAccount accountObj = new UserAccount();
FileWriter writer = new FileWriter("store.json", true);
accountObj.setUser(NewUserMethod());
accountObj.setID(NewIDMethod());
String json = gson.toJson(accountObj);
writer.write(json);
writer.close();
This makes the json file, which works - like this ::
{"USER":"noob123","ID":"99"}
When a new user does it, It will append the next line like so ::
{"USER":"noob123","ID":99}{"USER":"pro321","ID":100}
When I attempt to read this json file, I got the following error ::
"use JsonReader.setLenient(true) to accept malformed JSON at line 1, column 36"
So I understand it may be incorrect format and may need something like ::
{"ACCOUNT":{"USER":"noob123","ID":99},"ACCOUNT":{"USER":"pro321","ID":100}}
I have spent some time trying to create JSON in this format, or at least reference to the correct USER key when the matching USER name is used. Any help is greatly appreciated.
Thanks

You should use JSONArray to save this information into file. Then you can read content of file into list of UserAccount, add new object into this list.
Then you should override content of file.
E.g. :
UserAccount accountObj = new UserAccount();
accountObj.setUser(NewUserMethod());
accountObj.setID(NewIDMethod());
List<UserAccount> userAccounts = gson.fromJson(<jsonContent>, new TypeToken<List<UserAccount>>() {
}.getType());
userAccounts.add(accountObj);
String json = gson.toJson(userAccounts);
writer.write(json);
writer.close();

JSON Jackson + HTTPClient with german umlauts

I'm having a problem regarding a json string, i acquire with the Apache http client, containing german umlauts.
The mapping of json strings is only working, if the string does not contain any german umlaut, otherwise i get an "JsonMappingException: Can not deserialize instance of [...] out of START_ARRAY.
The Apache http client is set with "Accept-Charset" to HTTP.UTF-8, but as result i always get e.g. "\u00fc" instead "ü". When i manually replace e.g. "\u00fc" with "ü" the mapping works perfect.
How can i get a utf-8 encoded json response from Apache http client?
Or is the server output the problem?
params.setParameter(HttpProtocolParams.USE_EXPECT_CONTINUE, false);
HttpProtocolParams.setVersion(params, HttpVersion.HTTP_1_1);
HttpProtocolParams.setContentCharset(params, HTTP.UTF_8);
httpclient = new DefaultHttpClient(params);
httpclient = new DefaultHttpClient(params);
HttpGet httpGetContentLoad = new HttpGet(url);
httpGetContentLoad.setHeader("Accept-Charset", "utf-8");
httpGetContentLoad.setParams(params);
response = httpclient.execute(httpGetContentLoad);
entity = response.getEntity();
String loadedContent = null;
if (entity != null)
{
loadedContent = EntityUtils.toString(entity, HTTP.UTF_8);
entity.consumeContent();
}
if (HttpStatus.SC_OK != response.getStatusLine().getStatusCode())
{
throw new Exception("Loading content failed");
}
closeConnection();
return loadedContent;
And the json code is mapped here:
String jsonMetaData = loadGetRequestContent(getLatestEditionUrl(newspaperEdition));
Newspaper loadedNewspaper = mapper.readValue(jsonMetaData, Newspaper.class);
loadedNewspaper.setEdition(newspaperEdition);
Update 1:
JsonMetaData is type of String containing the fetched json code.
Update2:
This code i use to transform the json output to me needs:
public static String convertJsonLatestEditionMeta(String jsonCode)
{
jsonCode = jsonCode.replaceFirst("\\[\"[A-Za-z0-9-[:blank:]]+\",\\{", "{\"edition\":\"an-a1\",");
jsonCode = jsonCode.replaceFirst("\"pages\":\\{", "\"pages\":\\[");
jsonCode = Helper.replaceLast(jsonCode, "}}}]", "}]}");
jsonCode = jsonCode.replaceAll("\"[\\d]*\"\\:\\{\"", "\\{\"");
return jsonCode;
}
Update3:
Json conversion example:
jsoncode before conversion:
["Newspaper title",
{
"date":"20130103",
"pages":
{
"1": {"ressort":"ressorttitle1","pdfpfad":"pathToPdf1","number":1,"size":281506},
"2":{"ressort":"ressorttitle2","pdfpfad":"pathToPdf2","number":2,"size":281533},
[...]
}
}
]
Jsoncode after conversion:
{
"edition":"Newspaper title",
"date":"20130103",
"pages":
[
{"ressort":"Resorttitle1","pdfpfad":"pathToPdf1","number":1,"size":281506},
{"ressort":"Resorttitle2","pdfpfad":"pathToPdf2","number":2,"size":281533},
[...]
]
}
Solution:
I started using GSON as #Boris suggested and the problem regarding umlauts is gone! Further more GSON really seems to be faster than Jackson Json.
A workaround would be to replace the characters manually following this table:
Sign Unicode representation
Ä, ä \u00c4, \u00e4
Ö, ö \u00d6, \u00f6
Ü, ü \u00dc, \u00fc
ß \u00df
€ \u20ac

Try parsing like that:
entity = response.getEntity();
Newspaper loadedNewspaper=mapper.readValue(entity.getContent(), Newspaper.class);
No reason to go through String, Jackson parses InputStreams directly. Also Jackson will automatically detect the encoding if you use my proposed approach.
EDIT By the way consider using GSON JSON parsing library. It is even faster than Jackson and easier to use. However, Jackson recently started parsing XMl, too, which is a virtue.
EDIT2 After all you have added as details I would suppose the problem is with the server implementation of the services - the umlauts are not to be unicode escaped in the json - UTF 8 is native encoding for it. Why don't you instead of manually replace e.g. "\u00fc" with "ü" do it via regex?