Question

我正在尝试创建一个连接到API的应用程序。 Rigth现在我正在尝试连接到API并打印出结果。但是，出于某种原因，我不断收到以下错误：

Exception in thread "main" java.net.UnknownHostException: www.data.goteborg.se 
   at java.net.AbstractPlainSocketImpl.connect(Unknown Source) 
   at java.net.PlainSocketImpl.connect(Unknown Source) 
   at java.net.SocksSocketImpl.connect(Unknown Source) 
   at java.net.Socket.connect(Unknown Source) 
   at java.net.Socket.connect(Unknown Source) 
   at sun.net.NetworkClient.doConnect(Unknown Source) 
   at sun.net.www.http.HttpClient.openServer(Unknown Source) 
   at sun.net.www.http.HttpClient.openServer(Unknown Source) 
   at sun.net.www.http.HttpClient.<init>(Unknown Source) 
   at sun.net.www.http.HttpClient.New(Unknown Source) 
   at sun.net.www.http.HttpClient.New(Unknown Source) 
   at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(Unknown Source) 
   at sun.net.www.protocol.http.HttpURLConnection.plainConnect0(Unknown Source) 
   at sun.net.www.protocol.http.HttpURLConnection.plainConnect(Unknown Source) 
   at sun.net.www.protocol.http.HttpURLConnection.connect(Unknown Source) 
   at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(Unknown Source) 
   at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source) 
   at TestAPI.getHTML(TestAPI.java:14) 
   at TestAPI.main(TestAPI.java:29)

为什么会发生这种情况？贝娄是我的代码。提前致谢。

import java.io.*;
import java.net.*;

//import org.json.JSONObject;

public class TestAPI {


    public static String getHTML(String urlToRead) throws Exception {
        StringBuilder result = new StringBuilder();
        URL url = new URL(urlToRead);
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setRequestMethod("GET");
        BufferedReader rd = new BufferedReader(new InputStreamReader(conn.getInputStream()));
        String line;
        while ((line = rd.readLine()) != null) {
             result.append(line);
          }
        rd.close();
        return result.toString(); // JSON Object
    }


    public static void main(String[] args) throws Exception {

        System.out.println("Test1");

         String data;
         data = getHTML("http://data.goteborg.se/AirQualityService/v1.0/LatestMeasurement/"
                + "myAPIkey?format=Json");
         System.out.println(data);



    }

}

Answer 1

尝试连接www.data.goteborg.se。我认为您正在处理dns查找失败。

在this link中，您可以找到3种方法来修复 DNS_PROBE_FINISHED_NXDOMAIN 错误。

java.net.AbstractPlainSocketImpl.connect上的java.net.UnknownHostException（未知来源）

1 个答案: