I am trying to make a simple JSON-DB in Java since the current library on maven is horrendously overcomplicated. I have this method that takes in a key and value to put into a JSONObject and write it to my database.json
file.
public static void put(String path, String key, Object[] value){
//creates new JSONObject where data will be stored
JSONObject jsondb = new JSONObject();
try{
//adds key and value to JSONObject
jsondb.put(key, value);
} catch (JSONException e){
e.printStackTrace();
} //end try-catch
try(PrintWriter out = new PrintWriter(new FileWriter(path, true))) {
out.write(jsondb.toString());
out.write(',');
} catch (Exception e){
e.printStackTrace();
} //end try-catch
} //end put()
Here is my main method where I write some data to the file
public static void main(String[] args) throws Exception {
String path = "app.json";
Object[] amogus = {"Hello", 1, 2, 3, 4, 5};
Object[] amogus1 = {"Hello", 1, 2, 3, 4, 5, 6, 7, 8, 9, 0};
JsonDB db = new JsonDB(path);
db.put(path, "arr", amogus);
db.put(path, "arr1", amogus1);
}
What happens is that it save each data in a set of curly braces. So when I write to the file more than once like I do in my main method it saves it like this:
{"arr": ["Hello", 1, 2, 3, 4, 5]}{"arr1": ["Hello", 1, 2, 3, 4, 5, 6, 7, 8, 9, 0]}
This causes VSCode to throw an error since this isnt valid JSON. How would I make the method remove the curly braces and add commas to make the above JSON valid JSON? I cant seem to find the documentation for this library (The library is org.json on maven).
CodePudding user response:
This is a syntax issue. Your json
is not valid because the json
syntax want your data to be between curly braces like this:
{
"arr": ["Hello", 1, 2, 3, 4, 5],
"arr1": ["Hello", 1, 2, 3, 4, 5, 6, 7, 8, 9, 0]
}
instead of this, which is not a valid json
:
{"arr": ["Hello", 1, 2, 3, 4, 5]}
{"arr1": ["Hello", 1, 2, 3, 4, 5, 6, 7, 8, 9, 0]}
Create your data in your map object and let your json
library convert (serialize) your object in a valid json
.
CodePudding user response:
I solved this problem by reading all of the content in the file and appending the JSON object that I wanted to write to the file and then write it all at once.