单例模式封装网络工具类

用途：通过封装工具类和接口回调的方式来获取网络数据

package jiangguxu.example.com.myapplication.net;

import android.os.AsyncTask;

import com.google.common.io.CharStreams;

import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
//单例模式
public class NetUtils {
    private static final NetUtils ourInstance = new NetUtils();

    public static NetUtils getInstance() {
        return ourInstance;
    }

    private NetUtils() {
    }
    public void getDataFromService(String url){
        //向LoadData传递参数
        new LoadData().execute(url);
    }
//定义接口，接口回调
    public interface NetCallBack{
        void onSuccess(String result);
    }
    private NetCallBack netCallBack;

    public void setNetCallBack(NetCallBack netCallBack) {
        this.netCallBack = netCallBack;
    }
//具体实现解析的方法（此处直接返回了json）
    class LoadData extends AsyncTask<String,Void,String>{

        @Override
        protected String doInBackground(String... strings) {
            try {
                URL url = new URL(strings[0]);
                HttpURLConnection connection= (HttpURLConnection) url.openConnection();
                connection.setConnectTimeout(5000);

                connection.setConnectTimeout(5000);
                if (connection.getResponseCode()==HttpURLConnection.HTTP_OK){
                    return CharStreams.toString(new InputStreamReader(connection.getInputStream()));
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
            return null;
        }

        @Override
        protected void onPostExecute(String s) {
            netCallBack.onSuccess(s);
        }
    }
}