We Keep Coding

org.json.simple.JSONArray cannot be cast to org.json.simple.JSONObject at com.tpg.json.JsonParsing.main(JsonParsing.java:24)

I'm trying to read user id and user role from the following JSON file :
[https://drive.google.com/file/d/1X6t2kKaYArwM-mLc4EQhPAfUWF95RYTW/view?usp=sharing][1]
I have added both erp.json and class file in the same package : com.tpg.json
I'm using json simple jar file.
And facing the error : org.json.simple.JSONArray cannot be cast to org.json.simple.JSONObject
Could you suggest me the edits and re-post the code?
You can post your code or another code as well,which will give me the required output.
package com.tpg.json;
import java.io.File;
import java.io.FileReader;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
//com.googlecode.json-simple
public class JsonParsing {
public static void main(String[] args) {
ClassLoader classLoader = new JsonParsing().getClass().getClassLoader();
String fileName = "com/tpg/json/erp.json";
File file = new File(classLoader.getResource(fileName).getFile());
JSONParser parser = new JSONParser();
try {
FileReader reader = new FileReader(file.getAbsolutePath());
Object obj = parser.parse(reader);
JSONObject jsonObj = (JSONObject) obj;
JSONObject res = (JSONObject) jsonObj.get("Resources");
System.out.println("studentDetails :" + res.toJSONString());
JSONArray ID = (JSONArray) res.get("id");
System.out.println("Id" + ID);
} catch (Exception e) {
e.printStackTrace();
}
}
}

How to remove unnecessary object names in String of JSONArray?

I have JSONArray in String format as follows :
{
"productsList": [{
"map": {
"productSubcategory": "Levensverzekering",
"nameFirstInsured": "Akkerman"
}
},
{
"map": {
"productSubcategory": "Lineair dalend",
"nameFirstInsured": "Akkerman"
}
}
]
}
I want to convert this String as follows :
{
"productsList": [{
"productSubcategory": "Levensverzekering",
"nameFirstInsured": "Akkerman"
},
{
"productSubcategory": "Lineair dalend",
"nameFirstInsured": "Akkerman"
}
]
}
I have converted JSONArray to String so need operation as on the String on provided String in JSON format.
How I can change the String as required? What should I put in jsonString.replaceAll("","") function?

There is no easy way to do this, you have to do something like this.
OUTPUT IS:
{
"productsList":[
{
"productSubcategory":"Levensverzekering",
"nameFirstInsured":"Akkerman"
},
{
"productSubcategory":"Lineair dalend",
"nameFirstInsured":"Akkerman"
}
]
}
import java.io.FileReader;
import java.io.IOException;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
public class test {
public static void main(String[] args) throws IOException, InterruptedException {
JSONParser parser = new JSONParser();
JSONObject newObj = new JSONObject();
try {
Object obj = parser.parse(new FileReader("test.json"));
JSONObject jsonObject = (JSONObject) obj;
JSONArray arr = (JSONArray) jsonObject.get("productsList");
JSONArray newArr = new JSONArray();
for(int i = 0 ; i < arr.size();i++){
JSONObject object = (JSONObject) arr.get(i);
JSONObject a = (JSONObject) object.get("map");
newArr.add(a);
}
newObj.put("productsList", newArr);
System.out.println(newObj);
} catch (Exception e) {
e.printStackTrace();
}
}
}

Append text field data to an existing JSON file in java

I have a text field where user can enter data, once data is received i want to append it to existing JSON file.
I am able to read the existing data and getting the text field value, but while appending the new data with existing data I'm facing problem.
Error:
com.google.gson.JsonSyntaxException: com.google.gson.stream.MalformedJsonException: Use JsonReader.setLenient(true) to accept malformed JSON at line 1 column 18 path $
Below code :
JSON File :
{"vins":[{"vin":"544554"},{"vin":"54554"}]}
Text field value : String test ="3689";
so it should be appended as :
{"vins":[{"vin":"544554"},{"vin":"54554"},{"vin":"3689"}]}
Filereadwrite class :
public class JSONFIlewrite {
public static String Vinno_Read;
public static List<String> linststring;
public static void main(String[] args) {
try {
JSONParser parser = new JSONParser();
Object obj = parser.parse(new
FileReader("C:\\Amaresh\\Test\\sample_json.json"));
JSONObject jsonObject = (JSONObject) obj;
System.out.println(jsonObject);
linststring= new ArrayList();
// loop array
JSONArray msg = (JSONArray) jsonObject.get("vins");
Iterator iterator = msg.iterator();
while (iterator.hasNext()) {
Vinno_Read = iterator.next().toString();
linststring.add(Vinno_Read);
}
String list_string = "";
System.out.println(linststring);
for(String temp:linststring){
list_string += temp;
System.out.println("amar1"+list_string);
}
System.out.println("amar"+list_string);
Vin vin4 = new Vin();
vin4.setVin("76354273462");
Vins vins = new Vins();
vins.addVins(vin4);
Gson gson = new Gson();
//String jsonValue=list_string;
String jsonValue = gson.toJson(list_string).toString();
System.out.println("json--"+jsonValue);
Vins vins1 = gson.fromJson(jsonValue, Vins.class);
System.out.println("ddd"+vins1);
Vin vin = new Vin();
vin.setVin("544554");
vins1.addVins(vin);
jsonValue = gson.toJson(vins1).toString();
BufferedWriter writer = null;
try {
writer = new BufferedWriter(new FileWriter("C:\\Amaresh\\Test\\sample_json.json"));
writer.write(jsonValue);
System.out.println("Test"+jsonValue);
} catch (IOException e) {
} finally {
try {
if (writer != null)
writer.close();
} catch (IOException e) {
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
Setter Getter classes :
public class Vin {
#Expose
private String vin;
public String getVin() {
return vin;
}
public void setVin(String vin) {
this.vin = vin;
}
}
public class Vins {
#Expose
List<Vin> vins = new ArrayList<>();
public List<Vin> getVins() {
return vins;
}
public void addVins(Vin vin) {
this.vins.add(vin);
}
}

Main Logic:
you can see 4 blocks in the code
Reading the json file and parsing to a java Object
Casting de java Object to a JSonObject, parsing to a JsonArray and iterating the array printing the JsonElements
Creating a new Vin Object and converting it to a JSON String using Gson.toJson method (2nd part is not required only illustrative purposes)
Creating a JsonWriter, creating a Vins Object and loading it with the original JsonArray and then adding a new element (that correspondents to the new Vin Object created in step #3, finally writing the Vins Object to the [new] file.
Input:
{"vins":[{"vin":"544554"},{"vin":"54554"}]}
Output:
{"vins":[{"vin":"544554"},{"vin":"54554"},{"vin":"3689"}]}
Code
import java.io.FileReader;
import java.io.FileWriter;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import com.google.gson.Gson;
import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;
import com.google.gson.stream.JsonWriter;
public class JSONFIlewrite {
public static String Vinno_Read;
public static List<String> linststring;
public static void main(String[] args) {
try {
JsonParser parser = new JsonParser();
Object obj = parser.parse(new FileReader("C:\\Amaresh\\Test\\sample_json.json"));
JsonObject jsonObject = (JsonObject) obj;
System.out.println(jsonObject);
linststring = new ArrayList<String>();
// loop array
JsonArray msg = (JsonArray) jsonObject.get("vins");
Iterator<JsonElement> iterator = msg.iterator();
while (iterator.hasNext()) {
Vinno_Read = iterator.next().toString();
System.out.println("Vinno_Read---->" + Vinno_Read);
}
Vin newVin = new Vin();
newVin.setVin("3689");
Gson gson = new Gson();
String json = gson.toJson(newVin);
System.out.println("json---->" + json);
FileWriter file = new FileWriter("C:\\Amaresh\\Test\\sample_json2.json", false);
JsonWriter jw = new JsonWriter(file);
iterator = msg.iterator();
Vins vins = new Vins();
while (iterator.hasNext()) {
vins.addVin(gson.fromJson(iterator.next().toString(), Vin.class));
}
vins.addVin(newVin);
gson.toJson(vins, Vins.class, jw);
file.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
Notes:
Since I don't know what library you are using, I have updated the class names to be compatible to GSON.
I have also changed the method: public void addVins(Vin vin) in Vins Class to public void addVin(Vin vin)

To keep the existing content and append the new content to the end of JSON file:
Example1:
new FileWriter(file,true);
or you can try example02:
FileWriter file= new FileWriter(JSONLPATH,true)

How to parse large local JSON file to retrieve player names and more with an array

I have a large stream of data that I can capture from a game that I play using CharlesProxy. I'd like to parse the data and have it print out (eventually build an excel spreadsheet) the player names, x and y location, and the guild name.
The JSON data in Paste-Bin (you'll have to go down a few entries to see one of the results that actually returns a player name as well):
http://pastebin.com/v4kAaspn
Here's an example I found here that I tried to use to just return the player name, but I get a Null Pointer Exception error. Any advice will be greatly appreciated, thank you so much!
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.Iterator;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;
public class ToolMain {
public static void main(String[] args) {
JSONParser parser = new JSONParser();
try {
Object obj = parser.parse(new FileReader(
"//Users//Brandon//Desktop//JSONData.JSON"));
JSONObject jsonObject = (JSONObject) obj;
//get responses
JSONArray rsp = (JSONArray)jsonObject.get("responses");
//System.out.println(rsp);
//get return value
JSONObject rtvalue = (JSONObject)rsp.get(0);
//System.out.println(rtvalue);
//get hexes object
JSONObject hexes = (JSONObject)rtvalue.get("return_value");
//System.out.println(hexes);
//get hexes array
JSONArray hexesArray = (JSONArray)hexes.get("hexes");
Iterator<JSONObject> iterator = hexesArray.iterator();
while (iterator.hasNext()) {
JSONObject factObj = iterator.next();
String playerName = (String) factObj.get("player_name");
if (playerName != null) {
System.out.println(playerName);
}
}
//System.out.println(hexesArray);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (ParseException e) {
e.printStackTrace();
}
}
}

The NullPointerException is happening on below line because your JSONArray msg is null:
Iterator<JSONObject> iterator = msg.iterator();
Apply a check if(msg is not null) before you create an iterator on it.
Try it this way:
JSONObject jsonObject = (JSONObject) obj;
//get responses
JSONArray rsp = (JSONArray)jsonObject.get("responses");
System.out.println(rsp);
//get return value
JSONObject rtvalue = (JSONObject)rsp.get(0);
System.out.println(rtvalue);
//get hexes object
JSONObject hexes = (JSONObject)rtvalue.get("return_value");
System.out.println(hexes);
//get hexes array
JSONArray hexesArray = (JSONArray)hexes.get("hexes");
System.out.println(hexesArray);

How to convert a Java Object to a JSONObject?

i need to convert a POJO to a JSONObject (org.json.JSONObject)
I know how to convert it to a file:
ObjectMapper mapper = new ObjectMapper();
try {
mapper.writeValue(new File(file.toString()), registrationData);
} catch (JsonGenerationException e) {
e.printStackTrace();
} catch (JsonMappingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
But I dont want a file this time.

If we are parsing all model classes of server in GSON format then this is a best way to convert java object to JSONObject.In below code SampleObject is a java object which gets converted to the JSONObject.
SampleObject mSampleObject = new SampleObject();
String jsonInString = new Gson().toJson(mSampleObject);
JSONObject mJSONObject = new JSONObject(jsonInString);

If it's not a too complex object, you can do it yourself, without any libraries. Here is an example how:
public class DemoObject {
private int mSomeInt;
private String mSomeString;
public DemoObject(int i, String s) {
mSomeInt = i;
mSomeString = s;
}
//... other stuff
public JSONObject toJSON() {
JSONObject jo = new JSONObject();
jo.put("integer", mSomeInt);
jo.put("string", mSomeString);
return jo;
}
}
In code:
DemoObject demo = new DemoObject(10, "string");
JSONObject jo = demo.toJSON();
Of course you can also use Google Gson for more complex stuff and a less cumbersome implementation if you don't mind the extra dependency.

The example below was pretty much lifted from mkyongs tutorial. Instead of saving to a file you can just use the String json as a json representation of your POJO.
import java.io.FileWriter;
import java.io.IOException;
import com.google.gson.Gson;
public class GsonExample {
public static void main(String[] args) {
YourObject obj = new YourOBject();
Gson gson = new Gson();
String json = gson.toJson(obj); //convert
System.out.println(json);
}
}

Here is an easy way to convert Java object to JSON Object (not Json String)
import com.fasterxml.jackson.databind.ObjectMapper;
import org.json.simple.parser.JSONParser;
JSONObject jsonObject = (JSONObject) JSONValue.parse(new ObjectMapper().writeValueAsString(JavaObject));

How to get JsonElement from Object:
import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.gson.*;
final ObjectMapper objectMapper = new ObjectMapper();
final Gson gson = new Gson();
String json = objectMapper.writeValueAsString(source);
JsonElement result = gson.fromJson(json, JsonElement.class);