Connection请求数据工具类

创建一个Util包
创建以下两个 工具类
1、

package com.example.gridview.Utils;import android.os.AsyncTask;import java.io.IOException;import java.io.InputStream;import java.net.HttpURLConnection;import java.net.MalformedURLException;import java.net.URL;/** * 使用AsyncTask+HttpURLConnection请求数据 * Created by e531 on 2017/10/12. */public class MyTask extends AsyncTask<String,Void,String> {    //申请一个接口类对象    private  Icallbacks icallbacks;    //将无参构造设置成私有的，使之在外部不能够调用    private MyTask(){}    //定义有参构造方法    public MyTask(Icallbacks icallbacks) {        this.icallbacks = icallbacks;    }    @Override    protected String doInBackground(String... params) {        String str="";        try {             //使用HttpUrlConnection            URL url=new URL(params[0]);            HttpURLConnection connection=(HttpURLConnection) url.openConnection();            connection.setRequestMethod("GET");            connection.setReadTimeout(5000);            connection.setConnectTimeout(5000);            if(connection.getResponseCode()==200){                InputStream inputStream=connection.getInputStream();                //调用工具类中的静态方法                str=StreamToString.streamToStr(inputStream,"utf-8");            }        } catch (MalformedURLException e) {            e.printStackTrace();        }catch (IOException e){            e.printStackTrace();        }        return str;    }    @Override    protected void onPostExecute(String s) {        super.onPostExecute(s);        //解析，封装到bean,更新ui组件        icallbacks.updateUiByjson(s);    }    //定义一个接口    public interface Icallbacks{        /**         * 根据回传的json字符串，解析并更新页面组件         * @param jsonstr         */        void updateUiByjson(String jsonstr);    }}

2、

package com.example.gridview.Utils;import java.io.BufferedReader;import java.io.InputStream;import java.io.InputStreamReader;/** * Created by e531 on 2017/10/12. */public class StreamToString {    public static String streamToStr(InputStream inputStream,String chartSet){        StringBuilder builder=new StringBuilder();        try {            BufferedReader br=new BufferedReader(new InputStreamReader(inputStream,chartSet));            String con;            while ((con=br.readLine())!=null){                builder.append(con);            }            br.close();            return builder.toString();        } catch (Exception e) {            e.printStackTrace();        }        return "";    }}

3、在Activity里的具体使用方法

//根据要获取的数据所在Bean类所在的位置创建List集合存储获取的数据List<Bean.DataBean> list=new ArrayList<>();    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        //加载布局        setContentView(R.layout.activity_main);        //请求数据        MyTask myTask=new MyTask(new MyTask.Icallbacks() {   //工具类里的接口            @Override            public void updateUiByjson(String jsonstr) {                Gson gson=new Gson();    //gosn解析                Bean bean = gson.fromJson(jsonstr, Bean.class);                list=bean.getData();   //解析的数据赋值的刚创建的类                Log.i("nxx",list.toString());   //测试是否获取到数据            }        });        myTask.execute("http://api.expoon.com/AppNews/getNewsList/type/1/p/1");//执行方法，参数是网络接口    }

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/////package com.example.shuzu;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.text.LoginFilter;import android.util.Log;import org.json.JSONArray;import org.json.JSONException;import org.json.JSONObject;import java.util.ArrayList;import java.util.List;public class MainActivity extends AppCompatActivity {    private List<String > list=new ArrayList<>();    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        //加载页面        setContentView(R.layout.activity_main);        //        MyTask myTask=new MyTask(new MyTask.Icallbacks() {            @Override            public void updateUiByjson(String jsonstr) {                try {                    JSONArray array = new JSONArray(jsonstr);                    for (int i = 0; i < array.length(); i++) {                        String string = array.getString(i);                        list.add(string);                    }                    Log.i("nxx",list.toString());                } catch (Exception e) {                    e.printStackTrace();                }            }        });        myTask.execute("http://www.toutiao.com/hot_words/");    }}