//進(jìn)行流的讀寫
     byte[] buffer = new byte[1024 * 8];
     //創(chuàng)建一個(gè)寫到內(nèi)存的字節(jié)數(shù)組輸出流
     ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
     int len;
     while ((len = inputStream.read(buffer)) != -1) {
       byteArrayOutputStream.write(buffer,0,len);
       byteArrayOutputStream.flush();//不斷的刷新緩存
     }
     byteArrayOutputStream.close();//進(jìn)行關(guān)閉流通道
     result = byteArrayOutputStream.toString();//將寫入的字節(jié)流轉(zhuǎn)化為字符串

     //1.創(chuàng)建一個(gè)Url對(duì)象
       URL url = new URL(url_str);
     //2.獲取一個(gè)UrlConnection對(duì)象
       HttpURLConnection connection = (HttpURLConnection)url.openConnection();
     //3.為UrlConnection對(duì)象設(shè)置一些請(qǐng)求的參數(shù),請(qǐng)求方式，連接的超時(shí)時(shí)間 
       connection.setRequestMethod("GET");//設(shè)置請(qǐng)求方式
       connection.setConnectTimeout(1000*10);//設(shè)置超時(shí)時(shí)間
     //4.在獲取url請(qǐng)求的數(shù)據(jù)前需要判斷響應(yīng)碼，200 ：成功,206:訪問(wèn)部分?jǐn)?shù)據(jù)成功  300：跳轉(zhuǎn)或重定向 400：錯(cuò)誤 500：服務(wù)器異常
       int code = connection.getResponseCode();
       if(code == 200){
     //5.獲取有效數(shù)據(jù)，并將獲取的流數(shù)據(jù)解析成String
         InputStream inputStream = connection.getInputStream();
         String result = StreamUtils.streamToString(inputStream);

  1.主線程中創(chuàng)建一個(gè)Handler
    private Handler handler = new Handler(){
        public void handleMessage(android.os.Message msg) {


        };
    };
    2.重寫handler的handlermessage方法

    3.子線程中創(chuàng)建一個(gè)Message對(duì)象，將獲取的數(shù)據(jù)綁定給msg
        Message msg = new Message();
        //另一種方式：Message msg = Messge.obtain;
        msg.obj = result;
    4.主線程中的handler對(duì)象在子線程中將message發(fā)送給主線程
        handler.sendMessage(msg);

    5.主線程中handlermessage方法接受子線程發(fā)來(lái)的數(shù)據(jù)，就可以做更新UI的操作。

public class MainActivity extends AppCompatActivity {
  private EditText et_url;
  private Button btn_looksource;
  private TextView tv_sourceshow;


  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    //1，找到控件ID
    et_url = (EditText)findViewById(R.id.ev_url);
    btn_looksource = (Button)findViewById(R.id.btn_looksource);
    tv_sourceshow = (TextView)findViewById(R.id.source_show);
    //2，設(shè)置點(diǎn)擊事件
    btn_looksource.setOnClickListener(new View.OnClickListener() {
      @Override
      public void onClick(View v) {
        try {
          //3，獲取URL地址
          final String url_str = et_url.getText().toString().trim();
          //String results ="";
          //3.1進(jìn)行判斷URL是否為空
          if (TextUtils.isEmpty(url_str)) {
            Toast.makeText(MainActivity.this, "url地址不能為空的", Toast.LENGTH_SHORT).show();
            return;
          }
          System.out.println("oclick方法線程："+Thread.currentThread().getName());
          //創(chuàng)建子線程對(duì)象
          new Thread(new Runnable() {
            @Override
            public void run() {

            try {
              System.out.println("oclick方法runnable線程："+Thread.currentThread().getName());
              //4，請(qǐng)求URL地址
              //4.1創(chuàng)建一個(gè)URL對(duì)象
              URL url = new URL(url_str);
              //4.2獲取URLConnection對(duì)象
              HttpURLConnection connection = (HttpURLConnection) url.openConnection();
              //4.3位URLconnection設(shè)置請(qǐng)求參數(shù)
              connection.setRequestMethod("GET");
              connection.setConnectTimeout(5 * 1000);
              //4.4獲取請(qǐng)求響應(yīng)碼并進(jìn)行判斷
              int code = connection.getResponseCode();
              if (code == 200) {
                //4.5獲取數(shù)據(jù)并且解析成字符串
                InputStream inputStream = connection.getInputStream();
                //4.6進(jìn)行獲取string數(shù)據(jù)讀出來(lái)的
                String results = StreamUtils.streanTosting(inputStream);
                //5,將數(shù)據(jù)顯示到TExtview 上
                //tv_sourceshow.setText(results);
                //☆☆☆3.子線中創(chuàng)建一個(gè)Message對(duì)象，為了攜帶子線程中獲取的數(shù)據(jù)給主線程。
                //Message msg = new Message();
                //msg.obj = result;//將獲取的數(shù)據(jù)封裝到msg中。
                //☆☆☆4.使用handler對(duì)象將message發(fā)送到主線程。
                //handler.sendMessage(msg);
                Message msg = new Message();
                msg.obj = results;
                handler.sendMessage(msg);
              }
            }catch (Exception e) {
              e.printStackTrace();
            }

          }
          }).start();


        }catch (Exception e) {
          e.printStackTrace();
        }
      }
    });
  }
  //☆☆☆1.在主線程中創(chuàng)建一個(gè)Handler對(duì)象
  private Handler handler = new Handler(){
    //☆☆☆2.重寫handler的handlermessage方法,用來(lái)接收子線程中發(fā)來(lái)的消息
    public void handleMessage(android.os.Message msg) {
      //☆☆☆5.接收子線程發(fā)送的數(shù)據(jù)，處理數(shù)據(jù)。
      String result = (String) msg.obj;
      //☆☆☆6.當(dāng)前方法屬于主線程可以做UI的更新
      //五.獲取服務(wù)器返回的內(nèi)容，顯示到textview上
      tv_sourceshow.setText(result);
    };
  };
}

public class StreamUtils {
  public static String streanTosting(InputStream inputStream){
    String result = "";//保存字符串
    try {
      //進(jìn)行流的讀寫
      byte[] buffer = new byte[1024 * 8];
      //創(chuàng)建一個(gè)寫到內(nèi)存的字節(jié)數(shù)組輸出流
      ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
      int len;
      while ((len = inputStream.read(buffer)) != -1) {
        byteArrayOutputStream.write(buffer,0,len);
        byteArrayOutputStream.flush();//不斷的刷新緩存
      }
      byteArrayOutputStream.close();//進(jìn)行關(guān)閉流通道
      result = byteArrayOutputStream.toString();//將寫入的字節(jié)流轉(zhuǎn)化為字符串
    }catch (Exception e){
      e.printStackTrace();
    }
    return result;
  }
}