使用 java 从 url 读取 json 数据

Question

i haved read some answers like

Simplest way to read json from a URL in java

but it can not work.

ok,here is my code

package day1;

import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Scanner;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;

public class MainGet {

    public static void main(String[] args) {
        try {

            URL url = new URL("https://api.covid19api.com/summary");

            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setRequestMethod("GET");
            conn.connect();

            //Getting the response code
            int responsecode = conn.getResponseCode();

            if (responsecode != 200) {
                throw new RuntimeException("HttpResponseCode: " + responsecode);
            } else {

                String inline = "";
                Scanner scanner = new Scanner(url.openStream());

                //Write all the JSON data into a string using a scanner
                while (scanner.hasNext()) {
                    inline += scanner.nextLine();
                }

                //Close the scanner
                scanner.close();

                //Using the JSON simple library parse the string into a json object
                JSONParser parse = new JSONParser();
                JSONObject data_obj = (JSONObject) parse.parse(inline);

                //Get the required object from the above created object
                JSONObject obj = (JSONObject) data_obj.get("Global");

                //Get the required data using its key
                System.out.println(obj.get("TotalRecovered"));

                JSONArray arr = (JSONArray) data_obj.get("Countries");

                for (int i = 0; i < arr.size(); i++) {

                    JSONObject new_obj = (JSONObject) arr.get(i);

                    if (new_obj.get("Slug").equals("albania")) {
                        System.out.println("Total Recovered: " + new_obj.get("TotalRecovered"));
                        break;
                    }
                }
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}

i want a example that can run in eclipse. i haved install gson and i use jdk11.

here is my url: https://ws.yunlin.gov.tw/001/Upload/539/opendata/15369/1096/61b84dbc-5fe5-4569-8b94-4eebf1deef71.json

i want read it into java

thanks so much

i think i have added org.json into path,but still haved error

Answer 1

You have not provided error description. Assuming it's JSON parsing error. That URL does not return JSONObject but a JSONArray.

This is almost copy and paste solution.

https://mkyong.com/java/gson-how-to-parse-json-arrays-an-array-of-arrays/