HttpURlconntiuon获取网络数据

package Network;

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

import demo.text.com.mvpdemo.MainActivity;

/**
 * Created by Administrator on 2016/5/20.
 */
public class Checknetstate {

    public  static String  getjson(String str) {

       String   json_str = "";
        try {

            URL url = new URL(str);
            HttpURLConnection connection = null;
            connection = (HttpURLConnection) url.openConnection();
            connection.setConnectTimeout(5000);
            connection.setReadTimeout(5000);
            connection.setRequestMethod("GET");
            connection.connect();
            if (connection.getResponseCode() == 200) {
                InputStream inputStream = connection.getInputStream();
                //包装流
                BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
                String readline = "";
                StringBuffer buffer = new StringBuffer();
                //按行读取
                while ((readline = reader.readLine()) != null) {
                    buffer.append(readline);
                }
                json_str = buffer.toString();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

        return json_str;
    }
}