HttpUrlConnection

•HttpUrlConnection是java的标准类，继承UrlConnection类，二者都是抽象类。其对象主要通过URL的                                                 openConnection方法获得。

package com.sumzom.teach.httpurlconnection;

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 java.net.URLConnection;

import com.example.com.sumzom.getrequest.R;

import android.os.AsyncTask;
import android.os.Bundle;
import android.app.Activity;
import android.util.Log;
import android.view.Window;
import android.widget.TextView;

public class MainActivity extends Activity {

private TextView mTextView = null;
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.activity_main);
        String url = "http://www.weather.com.cn/data/sk/101010100.html";
       
        initWithView();
        new DownloadTextTask().execute(url);
       
    }

private void initWithView() {
  // TODO Auto-generated method stub
  mTextView = (TextView) findViewById(R.id.http_get);
     
 }

/**
     * @author 欧博泰克
     * @time 2015年9月23日
     * @contact QQ:2356066132
     * @instructions 采用httpUrlConnection进行网络传输；
     * */
 private InputStream openHttpCennection(String urlString) throws IOException{
  
  InputStream is = null;//建立/声明/创建/实例化一个输入流（这四种讲法都可以）
  
  int response = -1;//响应编码
  
  URL url = new URL(urlString);
  Log.i("openHttpCennection", urlString);
  //使用httpurlconnection打开网络连接；
  URLConnection urlConn = url.openConnection();
  
  HttpURLConnection httpConn = null;
  
  if (!(urlConn instanceof HttpURLConnection)) {
   
   throw new IOException("无效网络连接");
   
  }
  
  try {
   
   httpConn = (HttpURLConnection)urlConn;
   httpConn.setAllowUserInteraction(false);//设置允许用户交互
   httpConn.setInstanceFollowRedirects(true);//集实例遵循重定向
   httpConn.setRequestMethod("GET");
   //httpConn.setRequestProperty(field, newValue) //设置访问报头，简称报文
   httpConn.connect();
   response = httpConn.getResponseCode();//响应码，如果等于200则连接成功
   
   /**
    * resposeCode有两种表达方式：
    * 1:response == 200;
    * 2:response == HttpURLConnection;
    * */
   if (response == HttpURLConnection.HTTP_OK) {
    
    is = httpConn.getInputStream();//接受输入流
    
   }
   
  } catch (Exception e) {
   
   throw new IOException("网络连接错误");
  }
  
  return is;
  }
   
 /**
  * i/o流是伴随着数据的读写产生的
  * 1、获取输入流
  * 2、读取输入流
  * 3、将输入流写入buffer（作用，数据缓冲区）
  * 4、从数据流从buffer一行行读出
  * 5、返回读出的数据流
  * */
 private String downLoadText(String url){
  Log.i("downLoadText", "downLoadText");
  String resultData = "";
  
  try {
   InputStream is = openHttpCennection(url);
   //读取输入流
   InputStreamReader in = new InputStreamReader(is,"UTF-8");
   
   //为输入创建bufferedreader
   
   BufferedReader buffer = new BufferedReader(in);
   String inputLine = null;
   //循环读取网络获取数据
   //buffer缓冲区
   
   
   while ( (inputLine=buffer.readLine())!=null) {
    
    
    resultData += inputLine + "\n";
    
    Log.i("循环流读取", resultData);
    
   }
   
   //关闭流的读取（千万不能忘记）
   in.close();
   
  } catch (Exception e) {
   System.out.println("循环流读取"+resultData);
   e.printStackTrace();
  }
  
  return resultData;
 }
 
 private class DownloadTextTask extends AsyncTask<String, Void, String>{
  
  @Override
  protected String doInBackground(String... arg0) {
   // TODO Auto-generated method stub
   return downLoadText(arg0[0]);
  }
  
  @Override
  protected void onPostExecute(String result) {
   // TODO Auto-generated method stub
   super.onPostExecute(result);
   mTextView.setText(result); 
  }
  
 }
 
}