org.json.simple.JSONArray 不能强制转换为类 org.json.simple.JSONObjec

Question

我一直收到此错误，并且已经搜索了很多，似乎无法解决它。基本上，我正在尝试读取一个json文件并将其某些数据存储在数据库中。希望你们知道如何解决这个问题！ 这个json文件来自一个统计网站，我想将最重要的数据存储在我用SQLite创建的数据库表中。 感谢所有的帮助，欢呼:D

这是我不断得到的错误：

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)

这是我的 JSON 文件：

[ {
"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"
} ]
}
} ]

这是我的代码：

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();
}
}

Answer 1

将文件读入String并解析为JSONArray：

// 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();

将String转换为JSONArray：

String content = stringBuilder.toString();
// convert to json array
JSONArray json = new JSONArray(content);

逐个读取值：

JSONObject firstJsonObject = json.getJSONObject(1);

或循环访问JSONArray

for (int i = 0; i < json.length; i++){
JSONObject obj = json.getJSONObject(i);
// do something
}

希望这有帮助！！

Answer 2

改为用这样的东西进行测试。

Object object = (Object) jsonParser.parse(new FileReader("C:/Users/arrowplus/Desktop/jsonTest.json"));
JSONArray array = new JSONArray();
array.add(object);