首先第一個  解析流轉換成字串的工具類 StreamToString

import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;

import com.bwie.com.yuekaomoni.R
 
;


/**
 * 得到網路狀態的工具類
 * Created by e531 on 2017/10/16.
 */
public class NetStateUtil {

    /*
 * 判斷網路連線是否已開
 * true 已開啟  false 未開啟
 * */
public static boolean isConn(Context context){
        boolean bisConnFlag=false;
        ConnectivityManager conManager = (ConnectivityManager)context.getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo network = conManager.getActiveNetworkInfo();
        if(network!=null){
            bisConnFlag=conManager.getActiveNetworkInfo().isAvailable();
        }
        return bisConnFlag;
    }

    /**
     * 當判斷當前手機沒有網路時選擇是否開啟網路設定
     * @param context
*/
public static void showNoNetWorkDlg(final Context context) {
        AlertDialog.Builder builder = new AlertDialog.Builder(context);
        builder.setIcon(R.mipmap.ic_launcher)         //
.setTitle(R.string.app_name)            //
.setMessage("當前無網路").setPositiveButton("設定", new DialogInterface.OnClickListener() {

            @Override
public void onClick(DialogInterface dialog, int which) {
                // 跳轉到系統的網路設定介面
Intent intent = null;
                // 先判斷當前系統版本
if(android.os.Build.VERSION.SDK_INT > 10){  // 3.0以上
intent = new Intent(android.provider.Settings.ACTION_WIRELESS_SETTINGS);
                }else{
                    intent = new Intent();
                    intent.setClassName("com.android.settings", "com.android.settings.WirelessSettings");
                }
                context.startActivity(intent);

            }
        }).setNegativeButton("知道了", null).show();
    }
}

import android.os.AsyncTask;

import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

/**
 * Created by Administrator on 2018/1/11.
 */
public class MyTask extends AsyncTask<String,Void,String> {

    //申請一個介面類物件
private ICallBacks iCallBacks;
    //將無參構造設定成私有的，使外部不能夠呼叫
public MyTask() {
    }
    //定義有參構造方法
public MyTask(ICallBacks iCallBacks) {
        this.iCallBacks = iCallBacks;
    }

    @Override
protected String doInBackground(String... strings) {
        try {
            URL url=new URL(strings[0]);
            HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
            urlConnection.setRequestMethod("GET");
            urlConnection.setConnectTimeout(5000);
            urlConnection.setReadTimeout(5000);
            if (urlConnection.getResponseCode()==200){
                InputStream inputStream = urlConnection.getInputStream();
                //呼叫工具類中的靜態方法
String s = StreamToString.streamToString(inputStream);
                return s;
            }else if(urlConnection.getResponseCode()==301||urlConnection.getResponseCode()==302){
                //拿到重定向的地址
String newUrl = urlConnection.getHeaderField("location");
                URL u=new URL(newUrl);
                HttpURLConnection connection= (HttpURLConnection) u.openConnection();
                connection.setRequestMethod("GET");
                connection.setConnectTimeout(5000);
                connection.setReadTimeout(5000);
                if (connection.getResponseCode()==200){
                    InputStream inputStream = connection.getInputStream();
                    //呼叫工具類中的靜態方法
String s = StreamToString.streamToString(inputStream);
                    return s;
                }

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

        return null;
    }

    @Override
protected void onPostExecute(String s) {
        super.onPostExecute(s);
        iCallBacks.getJson(s);
    }

    //定義一個介面
public interface ICallBacks{
        void getJson(String json);
    }
}

import android.app.Application;
import android.os.Environment;
import android.util.Log;
import android.widget.Toast;

import com.nostra13.universalimageloader.cache.disc.impl.UnlimitedDiscCache;
import com.nostra13.universalimageloader.cache.disc.naming.Md5FileNameGenerator;
import com.nostra13.universalimageloader.core.ImageLoader;
import com.nostra13.universalimageloader.core.ImageLoaderConfiguration;

import java.io.File;

/**
 * Created by jane on 2018/1/3.
 * Application->Context 子類
 */
public class MyApplication extends Application {
    @Override
public void onCreate() {
        super.onCreate();

        Log.d("zzz","App入口");
        Toast.makeText(this,"app",Toast.LENGTH_SHORT).show();

        //自定義sd卡快取目錄 1.android預設cache-app被解除安裝時，快取的目錄一併被刪除    2.自定義
//        File cachefile=getExternalCacheDir();
File cachefile= new File(Environment.getExternalStorageDirectory().getPath()+"/images");
        //1.初使化--進行一下全域性配置 Application
ImageLoaderConfiguration configuration=new ImageLoaderConfiguration.Builder(this)
                .memoryCacheExtraOptions(400, 700)//快取圖片最大的長和寬
.threadPoolSize(3)//執行緒池的數量
.threadPriority(4)
                .memoryCacheSize(20*1024*1024)//設定記憶體快取區大小
.diskCacheSize(80*1024*1024)//設定sd卡快取區大小
.diskCache(new UnlimitedDiscCache(cachefile))//自定義sd卡快取目錄
.writeDebugLogs()//列印日誌內容
.diskCacheFileNameGenerator(new Md5FileNameGenerator())//給快取的檔名進行md5加密處理
.build();
        ImageLoader.getInstance().init(configuration);
    }
}