I am getting the clasCastException while processing the json data.
I want to get "employeeid" from a JSON response and want to write later the employee IDs in a new Excel file. However, I am getting the class cast exception - String can not be cast into an Object.
I have pasted my code below as I am new to this so your help will be really appreciated.
here is my JSON Response:
{
"msg": "Successful",
"displaycount": "50",
"totalcount": "1294",
"userdetails": [
{
"employeeid": "132421",
"userKey": 17
},
{
"employeeid": "112342",
"userKey": 18
},
{
"employeeid": "112341",
"userKey": 19
},
{
"employeeid": "112343",
"userKey": 20
},
{
"employeeid": "99954",
"userKey": 21
},
],
"errorCode": "0"
}
Code:
package api.src;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import com.opencsv.CSVWriter;
import java.io.*;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;
public class callAPI {
static String[] finalResult;
public static void main(String[] args) throws URISyntaxException, IOException, InterruptedException, ParseException {
HttpRequest request = HttpRequest.newBuilder()
.uri(URI.create("*****"))
.header("X-RapidAPI-Host", "***********")
.header("Content-Type", "application/json")
.header("Authorization",**********)
.method("POST", HttpRequest.BodyPublishers.noBody())
.build();
System.out.println("Connected "+request);
try {
String path = "D:/Sonika/JARs/httpresponse.json";
HttpResponse<String> response = null;
response = HttpClient.newHttpClient().send(request,
HttpResponse.BodyHandlers.ofString());
int statusCode = response.statusCode();
System.out.println(statusCode);
System.out.println(response.body());
try (PrintWriter out = new PrintWriter(new FileWriter(path))) {
out.write(response.body().toString());
}
JSONParser parse = new JSONParser();
JSONObject jobj = (JSONObject) parse.parse(new FileReader(path));
JSONArray jsonarr_1 = (JSONArray) jobj.get("userdetails");
//Get data for userdetails array
for (Object element : jsonarr_1) {
//Store the JSON objects in an array
//Get the index of the JSON object and print the values as per the index
JSONObject jsonobj_1 = (JSONObject)element;
finalResult = (String[]) jsonobj_1.get("employeeid");
System.out.println("\nEmployee ID: "+finalResult);
}
}
catch(IOException e) {
// handle not expected exception
e.printStackTrace();
}
}
public void writingCSVFile(){
try {
CSVWriter file = new CSVWriter(new FileWriter(new File("D:/Sonika/JARs/OutputExcelfile.xlsx")));
String[] colName = { "Employee ID"};
file.writeNext(colName);
file.writeNext(finalResult);
file.close();
}
catch (Exception e) {
e.printStackTrace();
}
}
}
okay let's make it bit simpler. Once you have the jsonString, you can do something like this -
List<String> employeeIds = new ArrayList<>();
JSONObject obj = new JSONObject(jsonString);
if (obj.has("userdetails")) {
// get the userDetails array object
JSONArray userDetails = obj.getJSONArray("userdetails");
// loop over
for (int i = 0; i < userDetails.length(); i++) {
JSONObject object = (JSONObject) userDetails.get(i);
employeeIds.add(object.getString("employeeid"))
}
}
Later you can write the employeeIds list in any file you want
EDITED
here is the code to write in csv file
public static void writeInCsv(List<String> employeeIds, String directoryLocation) {
String fileName = directoryLocation + "/empoyeeIds.csv" ;
try (BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(fileName), StandardCharsets.UTF_8))) {
String header = "Employee Ids";
bw.write(header);
bw.newLine();
for (String id : employeeIds) {
bw.write(id);
bw.newLine();
}
} catch (UnsupportedEncodingException e) {
LOG.error("Unsupported encoding format", e);
} catch (FileNotFoundException e) {
LOG.error("Error creating the file ", e);
} catch (IOException e) {
LOG.error("Error creating csv file", e);
}
}