I keep getting this error and already searched a lot and cant seem to solve it. Basically i am trying to read a json file and store some of its data in a database. Hope you guys know how to solve this! This json file is from a statistics site and i want to store the most important data in a database table i created with SQLite. Thanks for all the help, cheers 😀
This is the error i keep getting:
JavaScript
x
java.lang.ClassCastException: class org.json.simple.JSONArray cannot be cast to class org.json.simple.JSONObject (org.json.simple.JSONArray and org.json.simple.JSONObject are in unnamed module of loader 'app')
at com.arrowplus.arrowplus.Connect.connect(Connect.java:49)
at com.arrowplus.arrowplus.Connect.main(Connect.java:86)
This is my JSON file:
JavaScript
[ {
"IndicadorCod" : "0010042",
"IndicadorDsg" : "Valor mediano de avaliação bancária (€/ m²) por Localização geográfica (Município - 2013) e Tipo de construção; Mensal - INE, Inquérito à avaliação bancária na habitação",
"MetaInfUrl" : "https://www.ine.pt/bddXplorer/htdocs/minfo.jsp?var_cd=0010042&lingua=PT",
"DataExtracao" : "2020-06-29T15:55:51.640+01:00",
"DataUltimoAtualizacao" : "2020-06-29",
"UltimoPref" : "Maio de 2020",
"Dados" : {
"202005" : [ {
"geocod" : "1701106",
"geodsg" : "Lisboa",
"dim_3" : "T",
"dim_3_t" : "Total",
"valor" : "3084"
} ]
}
} ]
And this is my code:
JavaScript
package com.arrowplus.arrowplus;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.sql.*;
import org.json.simple.JSONObject;
import org.json.simple.JSONArray;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;
import java.sql.Connection;
import java.sql.DriverManager;
public class Connect {
public static Connection ConnectToDB() throws Exception {
Connection conn = null;
// db parameters
String url = "jdbc:sqlite:C:/sqlite/AP.db";
// create a connection to the database
conn = DriverManager.getConnection(url);
System.out.println("Connection to SQLite has been established.");
return conn;
}
public static void connect() {
//Creating a JSONParser object
JSONParser jsonParser = new JSONParser();
try {
//Parsing the contents of the JSON file
JSONObject jsonObject = (JSONObject) jsonParser.parse(new FileReader("C:/Users/arrowplus/Desktop/jsonTest.json"));
//Retrieving the array
JSONArray jsonArray = (JSONArray) jsonObject.get("");
Connection con = ConnectToDB();
PreparedStatement pstmt = con.prepareStatement("INSERT INTO ine_data values (id, date, valor, DataUltimoAtualizacao, geodsg)");
for (Object object : jsonArray) {
JSONObject record = (JSONObject) object;
int id = Integer.parseInt((String) record.get("id"));
String date = (String) record.get("date");
int valor = Integer.parseInt((String) record.get("valor"));
String dateUpdate = (String) record.get("DataUltimoAtualizacao");
long dateUpdate2 = Date.valueOf(dateUpdate).getTime();
String city = (String) record.get("geodsg");
pstmt.setInt(1, id);
pstmt.setString(2, date);
pstmt.setInt(3, valor);
pstmt.setDate(4, new Date(dateUpdate2));
pstmt.setString(5, city);
pstmt.executeUpdate();
}
System.out.println("Records inserted.....");
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (ParseException e) {
e.printStackTrace();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
/**
* @param args the command line arguments
*/
public static void main (String[]args){
connect();
}
}
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Answer
Read file into String
and parse as JSONArray
:
JavaScript
// Read file into a string
BufferedReader reader = new BufferedReader(new FileReader(fileName));
StringBuilder stringBuilder = new StringBuilder();
String line = null;
String ls = System.getProperty("line.separator");
while ((line = reader.readLine()) != null) {
stringBuilder.append(line);
stringBuilder.append(ls);
}
// delete the last new line separator
stringBuilder.deleteCharAt(stringBuilder.length() - 1);
reader.close();
Convert the String
to a JSONArray
:
JavaScript
String content = stringBuilder.toString();
// convert to json array
JSONArray json = new JSONArray(content);
Read values one by one:
JavaScript
JSONObject firstJsonObject = json.getJSONObject(1);
or iterate through the JSONArray
JavaScript
for (int i = 0; i < json.length; i++){
JSONObject obj = json.getJSONObject(i);
// do something
}
Hope this helps !!