是否有网络

private void setThread() {
    mThread=new Thread(){
        @Override
        public void run() {
            super.run();
            if (Ntil.isNetworkAvailable(CS2Activity.this)){
            mResponse=Ntil.sendData("http://192.168.1.118:8080/classserver/readPartInfo");
                Log.i("调试",mResponse);
            parseData();
             mHandler.sendEmptyMessage(UP_DATA);
            }else {
                mHandler.sendEmptyMessage(NET);
            }
        }
    };
}

package com.example.rachel.ytceshi;

import android.content.Context;
import android.net.ConnectivityManager;

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

/**
 * Created by Rachel on 2017/3/6.
 */
public class Ntil {
    private static HttpURLConnection con;
    private  static BufferedReader buff;

    public static boolean isNetworkAvailable(Context context) {
        boolean is=false;
        ConnectivityManager conManager= (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        if (null==conManager||null==conManager.getActiveNetworkInfo()){
            is=false;
        }else {
            is=true;
        }

        return is;
    }

    public static String sendData(String s) {
        String mResult="";
        try {
            createConnectiom(s);
            setParams();
            mResult=readData(mResult);
            return mResult;
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            if (buff!=null){
                try {
                    buff.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
return  mResult;
    }

    private static String readData(String mResult) {
        try {
           buff=new BufferedReader(new InputStreamReader(con.getInputStream()));
            String line;
            if ((line=buff.readLine())!=null){
                if (mResult.equals("")){
                    mResult+=line;
                }else {
                    mResult+="
"+line;
                }


            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return mResult;
    }

    private static void createConnectiom(String s) {
        try {
            URL murl=new URL(s);
               con  = (HttpURLConnection) murl.openConnection();
            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();

        }
    }

    private static void setParams() {
        con.setConnectTimeout(20*1000);
        con.setReadTimeout(20*1000);
        con.setDoInput(true);
        con.setDoOutput(true);
    }
}