HttpUrlConnection 网络连接

导包
import java.io.BufferedReader;import java.io.InputStream;import java.io.InputStreamReader;import java.net.HttpURLConnection;import java.net.URL;

public class HttpUrlConnection {    public static String getJson(String urldata) {        try {            URL url = new URL(urldata);            HttpURLConnection httpurlConnection = (HttpURLConnection) url.openConnection();            httpurlConnection.setRequestMethod("GET");            httpurlConnection.setReadTimeout(8000);            int responseCode = httpurlConnection.getResponseCode();            if (responseCode == 200) {                InputStream inputStream = httpurlConnection.getInputStream();                StringBuilder stringBuilder = new StringBuilder();                BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));                String json = "";                while ((json = bufferedReader.readLine()) != null) {                    stringBuilder.append(json);                }                return stringBuilder.toString();            }        } catch (Exception e) {            e.printStackTrace();        }        return "";    }}