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Pretty print for JSON in Java works fine for the console, but in browser it does not work

I have a JSON file and I want to retrieve its content from a API call within a rest controller created in Java Spring Boot.
I get the content of the .json file into a String and use the below method ( one of them ) in order to pretty print.
If I system.out.println() the output, it gets pretty printed, but in the browser it is displayed roughly and with no indentation. I had more approaches :
String content = new String(Files.readAllBytes(resource.toPath()));
Gson gson = new GsonBuilder().setPrettyPrinting().create();
JsonParser jp = new JsonParser();
JsonElement je = jp.parse(content);
String prettyJsonString = gson.toJson(je);
System.out.println(prettyJsonString);
return prettyJsonString;
The other approach returns the same ugly output in browser, but it also adds "/r/n":
ObjectMapper mapper = new ObjectMapper();
mapper.enable(SerializationFeature.INDENT_OUTPUT);
String prettyJsonString = mapper.writeValueAsString(content);
return prettyJsonString;
Can anyone help me get the pretty output in browser as well?

Formatting String for console output and for HTML output are two VERY different tasks. Method setPrettyPrinting() is for console printing. HTML browser will ignore "\n" symbols and will not respect multiple spaces replacing them with a single space etc. In general, it is usually a client-side task to format the output. But I delt once with this problem and wrote a method that takes a console-formatted string and converts it to Html formatted String. For instance, it replaces all "\n" symbols with br Html tags. It does some other things as well. I had some success with it, but sometimes some unexpected problems occurred. You are welcome to use it. The method is available in MgntUtils Open source library. Here is its JavaDoc. The library itself is available as Maven artifact here and on Github (including source code and JavaDoc) here. An article about the library is here. Your code would look like this:
String htmlString = TextUtils.formatStringToPreserveIndentationForHtml(jsonPrettyString);

I had this same problem and stumbled upon how to get it to pretty print in the browser.
In your application.properties file, add these two lines:
# Preferred JSON mapper to use for HTTP message conversion.
spring.mvc.converters.preferred-json-mapper=gson
# Whether to output serialized JSON that fits in a page for pretty printing.
spring.gson.pretty-printing=true
Reference: https://www.callicoder.com/configuring-spring-boot-to-use-gson-instead-of-jackson/
Maybe related: https://stackoverflow.com/a/62044963

How to create new text file on the fly if one file overflow in java

I am writing json data into one file. It works fine for small data but for large data it is writing some amount of data and remaining data gets skipped. So Please guide me how to create new file if one gets fulled in java?
Currently i am using below code to write json object into a file.
Below is the sample which is quite similar to my working code.
String json=null;
for(int counter=0;counter<2;counter++){
JSONObject obj=new JSONObject();
JSONObject second=new JSONObject();
obj.put("ClassName", "sample.com");
obj.put("Query", "query");
obj.put("Message", "Successfylly");
second.put("Number"+sequence++, obj);
company.add(second);
//file.write(obj.toJSONString());
Gson gson = new GsonBuilder().setPrettyPrinting().create();
json = gson.toJson(company);
file.write(json);
file.close();
}
Please guide me how to create new file if existing file gets fulled while writing json object into a text file.

It's difficult to tell, as your code is not formatted well, but it looks like every iteration of your loop is overwriting the variable json. Only the value of json at the last iteration of the loop will be written to the file.
Move the call to file.write(json) inside the loop.

How to get a string out of (libgdx) json

I really wonder how this would be done properly(*):
FileHandle file = Gdx.files.local("test.json");
Json json = new Json(JsonWriter.OutputType.json);
JsonWriter writer = new JsonWriter(new StringWriter());
json.setWriter(writer);
json.writeObjectStart();
json.writeValue("name", "Testing");
json.writeObjectEnd();
file.writeString(..., false); // Here I am stuck
As you can see I want to manually (!) create a json object and write just one string in there. I do not want to use a serializer or anything the like for this matter.
In https://github.com/libgdx/libgdx/wiki/Reading-&-writing-JSON there is a passage: Serialization Methods
In there the same is done. But how can I translate my Json to a String that can be written to a file? toString() is doing no good here.
(*) Once again, I want to emphasize I do NOT want to use a serializer in that case but build my own json-file from scratch. I'm totally aware of the problems and unmanagable-code this could lead to. Thank you!

How to convert an java serialized file to json file

I have a java class already serialized and stored as .ser format file but i want to get this converted in json file (.json format) , this is because serialization seems to be inefficient in terms of appending in direct manner, and further cause corruption of file due streamcorruption errors. Is there a possible efficient way to convert this java serialized file to json format.

You can read the .ser file as an InputStream and map the object received with key/value using Gson and write to .json file
InputStream ins = new ObjectInputStream(new FileInputStream("c:\\student.ser"));
Student student = (Student) ins.readObject();
Gson gson = new Gson();
// convert java object to JSON format,
// and returned as JSON formatted string
String json = gson.toJson(student );
try {
//write converted json data to a file named "file.json"
FileWriter writer = new FileWriter("c:\\file.json");
writer.write(json);
writer.close();
} catch (IOException e) {
e.printStackTrace();
}

There is no standard way to do it in Java and also there is no silver bullet - there are a lot of libraries for this. I prefer jackson https://github.com/FasterXML/jackson
ObjectMapper mapper = new ObjectMapper();
// object == ??? read from *.ser
String s = mapper.writeValueAsString(object);
You can see the list of libraries for JSON serialization/deserialization (for java and not only for java) here http://json.org/
this is because serialization seems to be inefficient in terms of appending in direct manner
Not sure if JSON is the answer for you. Could you share with us some examples of data and what manipulations you do with it?

You can try Google Protocol Buffers as alternative to Java serialization and JSON.
In my answer in topic bellow there is an overview of what GPB is and how to use, so you may check that and see if it suits you:
How to write/read binary files that represent objects?

Adding elements to an JSON object in a external JSON file?

(After months of surfing the internet, talking to the school's computing department and try code out, I still don't get how to do it, but I do know more specific about what I trying to do)
Previously I said I want to "Add lines" to a existing JSON file.
What I want to do is simply add an element to an JSON object from a file, then save the file.
However I am still confused about how to do it.
The process I am guessing is to use ajax to load the content of the file (the JSON code in the file) into a variable then add the new element into the object then save the file.
I have seen a lot of code but are all just too confusing and looks like its for webpages. I am trying to edit a file on the computer as a program which I think webpage related code such as xmlhttp requests are irrelevant as the file is in a folder in appdata.
I have been confused and thought Java and Javascript were the same thing, I know now they're not.
What code or functions would I look for and how would it be used in the code?
(Please don't post pseudocode because I have no idea how to write the code for them since I have literally no idea how to code anything other than a html webpage and some php. Other coding language like Java, Javascript and Python I have little knowledge with but not enough to write a program alone.)

I think it would be best to use code that somebody else has already written to manipulate the JSON. There are plenty of libraries for that, and the best would be the officially specified one, JSON-P. What you would do is this:
Go to http://jsonp.java.net/ and download JSON-P. (You will have to examine the page carefully to find the link to "JSON Processing RI jar".) You will need to include this JAR in your class path while you write your program.
Add imports to your program for javax.json.*.
Write this code to do the job (you will have to catch JsonExceptions and IOExceptions):
JsonReader reader = Json.createReader(new FileReader("launcher_profiles.json"));
JsonObject file = reader.readObject();
reader.close();
JsonObject profiles = file.getJsonObject("profiles");
JsonObject newProfile = Json.createObjectBuilder()
.add("name", "New Lines")
.add("gameDir", "New Lines")
.add("lastVersionId", "New Lines")
.add("playerUUID", "")
.build();
JsonObjectBuilder objectBuilder = Json.createObjectBuilder()
.add("New Profile Name", newProfile);
for (java.util.Map.Entry<String, JsonValue> entry : profiles.entrySet())
objectBuilder.add(entry.getKey(), entry.getValue());
JsonObject newProfiles = objectBuilder.build();
// Now, figure out what I have done so far and write the rest of the code yourself! At the end, use this code to write out the new file:
JsonWriter writer = Json.createWriter(new FileWriter("launcher_profiles.json"));
writer.writeObject(newFile);
writer.close();