We Keep Coding

Org json parsing keep getting error - is not a JSONObject

Im trying to parse id from following string json:
postResponse :{"success":true,"response_json":"{\"status\":200,\"message\":\"Success\",\"data\":{\"id\":\"f71233gg12\"}}"}
my code looks like below:
System.out.println("postResponse :"+postResponse);
JSONObject responseJson = new JSONObject(postResponse);
JSONObject jsonObjectA = responseJson.getJSONObject("response_json");
JSONObject jsonObjectB = jsonObjectA.getJSONObject("data");
String the_pdf_id = jsonObjectB.get("id").toString();
i keep getting the error:
org.json.JSONException: JSONObject["response_json"] is not a JSONObject.
what could be the reason? any solution for that?

As you can see on your data, the content at key response_json is not a an object, but only a string, another JSON-encoded string
// response_json value is a string
{"success":true,"response_json":"{\"status\":200,\"message\":\"Success\",\"data\":{\"id\":\"f71233gg12\"}}"}
// response_json value is an object
{"success":true,"response_json": {"status":200,"message":"Success","data":{"id":"f71233gg12"}}}
You need a second parse level
JSONObject jsonObjectA = new JSONObject(responseJson.getJSONString("response_json"));

Why am I getting a JSON exception while calling .getJSONObject()?

I want to generate JSON with URI within the JSON response but I'm getting JSON exception when I tried to get a value of the key. Here fragmentdataservice is to get JSON data and it working fine and I'm working on API creation with content fragments.
String requestURI = req.getRequestURI();
String contentFragmentName = requestURI.substring(requestURI.indexOf('.') +
1, requestURI.lastIndexOf('.'));
resp.setContentType("application/json");
response = fragmentDataService.getContentFragment(contentFragmentName);
String contentReference = response.getJSONObject("poolingInfo").toString();
JSONObject contentData = fragmentDataService.getContentFragment(contentReference);
response.put("poolingInfo", contentData);

JSON exception will be thrown if you're trying to read a String data or a JSONArray data as a JSONObject using getJSONObject() method.
If you're not sure what's the type of object that's being returned then first use:
Object temp = response.get("poolingInfo");
if(null != temp && temp instanceof JSONObject) {
String contentReference = ((JSONObject) temp).toString();
}

How to get the values from keys in nested objects using only json-simple

I want to get only a specific value out of all the nested objects. In the application I just need the msg 3 which is inside another object messages.
I have tried it using JSONObject but it is not working for nested object. However It is working with just a single object means root object .
INPUT - {"name":"lola","messages":{"msg 1":"msg 2","msg 3":"msg 4"},"age":22}
String s = sc.nextLine();
JSONParser parser = new JSONParser();
JSONObject json = (JSONObject) parser.parse(s);
System.out.println(json);
Object name = json.get("messages");
System.out.println(name);
JSONObject messageObject = (JSONObject) json.get("messages");
System.out.println(employeeObject);
//Get employee first name
String msg= (String) messageObject.get("msg3");
System.out.println(msg);
The Output:
{"msg 3":"msg 4","msg 1":"msg 2"}
{"msg 3":"msg 4","msg 1":"msg 2"}
null
The last nested object is not fetching in any way. Another thing is that the normal print of the string as a JSONObject gets changed. like the msg3 came before msg1.
In place of null - msg4 should be there.
Thanks in advance.

You are missing a space between "msg" and "3". By the way - you can do this easier, as such.
String s = sc.nextLine();
JSONParser parser = new JSONParser();
JSONObject json = (JSONObject) parser.parse(s);
System.out.println(json);
System.out.println(json.get("message").get("msg 3"));

Parsing a JSON file in Java using json-simple

I have created a .json file:
{
"numbers": [
{
"natural": "10",
"integer": "-1",
"real": "3.14159265",
"complex": {
"real": 10,
"imaginary": 2
},
"EOF": "yes"
}
]
}
and I want to parse it using Json Simple, in order to extract the content of the "natural" and the "imaginary".
This is what I have written so far:
JSONParser parser = new JSONParser();
Object obj = parser.parse(new FileReader("...")); //the location of the file
JSONObject jsonObject = (JSONObject) obj;
String natural = (String) jsonObject.get("natural");
System.out.println(natural);
The problem is that the value of natural is "null" and not "10". Same thing happens when I write jsonObject.get("imaginary").
I have looked at many websites (including StackOverflow), I have followed the same way most people have written, but I am unable to fix this problem.

You need to find the JSONObject in the array first. You are trying to find the field natural of the top-level JSONObject, which only contains the field numbers so it is returning null because it can't find natural.
To fix this you must first get the numbers array.
Try this instead:
JSONParser parser = new JSONParser();
Object obj = parser.parse(new FileReader("...")); //the location of the file
JSONObject jsonObject = (JSONObject) obj;
JSONArray numbers = (JSONArray) jsonObject.get("numbers");
for (Object number : numbers) {
JSONObject jsonNumber = (JSONObject) number;
String natural = (String) jsonNumber.get("natural");
System.out.println(natural);
}

The object in your file has exactly one property, named numbers.
There is no natural property.
You probably want to examine the objects inside that array.

Adding on to #Jermey Hanion's answer and comment, here is what I did to get "imaginary" and "natural"
JSONParser parser = new JSONParser();
Object obj = parser.parse(new FileReader("...")); //the location of the file
JSONObject jsonObject = (JSONObject) obj;
JSONArray numbers = (JSONArray) jsonObject.get("numbers");
for (Object number : numbers) {
JSONObject jsonNumber = (JSONObject) number;
String natural = (String) jsonNumber.get("natural");
JSONObject complex = (JSONObject) jsonNumber.get("complex");
String imaginary = (String) complex.get("imaginary");
System.out.println(natural);
}
Jeremey's answer for getting imaginary is not correct, or maybe it was correct. The above snippet is to my knowledge working on my project.
PS. Sorry for reviving the thread but I thought it would be a useful resource for people looking to learn JSON.simple

How to modify the JSON data and return the updated JSON data

We have a requirement to update the JSON data in middle and need to return the updated JSON data using java. Also it should support any type of JSON data.
ex:
Assume {object:{"color":"red","shape":"Triangle"}} is the JSON data and in this we need to update the shape value to Rectangle and we need to return the updated JSON data as below:
{object:{"color":"red","shape":"Rectangle"}}
For this we need to pass the element path ( which element we need to update) and updateText and JSON Data to the JAVA code.
here is the methodCall:
updateValue("object/shape", "Rectangle", "{object:{"color":"red","shape":"Triangle"}}")
We tried below code using Gson library. But with this code we are able to update the targeted Json element, but the requirement is to return the entire JSON data with the updated value.
So please suggest how do we re-build the JSON data with the updated text.
Below is the code we tried to update the Json Data.
public String updateValue(String keyPath, String updateText, String jsonText) {
String[] keys = keyPath.split("/");
JsonParser jsonParser = new JsonParser();
JsonObject jsonObject = (JsonObject) jsonParser.parse(jsonText);
String result = "";
for(String key : keys)
{
if (jsonObject.get(key) instanceof JsonObject)
{
jsonObject = (JsonObject)jsonObject.get(key);
}
else if(jsonObject.get(key) instanceof JsonArray)
{
JsonArray jsonArray = (JsonArray)jsonObject.get(key);
result = jsonArray.toString();
}
else
{
result = jsonObject.get(key).toString();
}
}
result = result.replace(result, updateText);
return result;
}

The problem lies in the way you do the replacements. When you translate the JsonObject to String, you lose the object, and after replacement, you just have the replaced String. To fix it, you need to operate directly on the object, instead of the String counterpart. Because JsonObject is mutable, holding a reference to the input will reflect the changes. One drawback is you can't replace a value in a JsonArray this way, partly because you don't know which element to replace. To accomplish that, you will need a little more in the input(either the value to replace or the element position).
public String updateValue(String keyPath, String updateText, String jsonText) {
String[] keys = keyPath.split("/");
JsonParser jsonParser = new JsonParser();
JsonObject jsonObject = (JsonObject) jsonParser.parse(jsonText);
JsonObject returnVal = jsonObject; // This holds the ref to target json object
JsonPrimitive jp = new JsonPrimitive(updateText);
String finalKey = keys[keys.length - 1];
for(String key : keys)
{
if (jsonObject.get(key).isJsonObject())
{
jsonObject = (JsonObject)jsonObject.get(key);
}
}
jsonObject.remove(finalKey);
jsonObject.add(finalKey, jp);
return returnVal.toString();
}

You can use JsonPath lib for that and try using the following code.
private static final Configuration configuration = Configuration.builder()
.jsonProvider(new JacksonJsonNodeJsonProvider())
.mappingProvider(new JacksonMappingProvider())
.build();
JsonNode updatedJson = JsonPath.using(configuration).parse(originaljson)
.set("use the path to go for value", "new value").json();
json = updatedJson.toString();