<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical"

    tools:context=".MainActivity" >

    <EditText

        android:id="@+id/et_path"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:text="http://192.168.1.100:8080/hello.jsp" />

    <Button

        android:onClick="click"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:text="查看源码" />

    <ScrollView

        android:layout_width="fill_parent"

        android:layout_height="fill_parent" >

        <TextView

            android:id="@+id/tv_result"

            android:layout_width="fill_parent"

            android:layout_height="fill_parent" />

    </ScrollView>

</LinearLayout>

 package com.itheima.netsourceviewer;

 import java.io.InputStream;

 import java.net.HttpURLConnection;

 import java.net.URL;

 import android.app.Activity;

 import android.os.Bundle;

 import android.os.Handler;

 import android.os.Message;

 import android.view.View;

 import android.widget.EditText;

 import android.widget.TextView;

 import android.widget.Toast;

 import com.itheima.netsourceviewer.utils.StreamTools;

 public class MainActivity extends Activity {

     protected static final int SUCCESS = 1;

     protected static final int ERROR = 2;

     private EditText et_path;

     private TextView tv_result;

     private Handler handler = new Handler(){

         public void handleMessage(android.os.Message msg) {

             switch (msg.what) {

             case SUCCESS:

                 String text = (String) msg.obj;

                 tv_result.setText(text);

                 break;

             case ERROR:

                 Toast.makeText(MainActivity.this, "请求失败", 1).show();

                 break;

             }

         };

     };

     @Override

     protected void onCreate(Bundle savedInstanceState) {

         super.onCreate(savedInstanceState);

         setContentView(R.layout.activity_main);

         et_path = (EditText) findViewById(R.id.et_path);

         tv_result = (TextView) findViewById(R.id.tv_result);

     }

     /**

      * 查看源文件的点击事件

      * @param view

      */

     public void click(View view){

         final String path = et_path.getText().toString().trim();

         //访问网络，把html源文件下载下来

         new Thread(){

             public void run() {

                 try {

                     //获取url对象

                     URL url = new URL(path);

                     //获取链接对象

                     HttpURLConnection conn = (HttpURLConnection) url.openConnection();

                     //获取请求方式，默认GET

                     conn.setRequestMethod("GET");//声明请求方式 默认get

                     //告诉服务器我是什么样的客户端

                     conn.setRequestProperty("User-Agent", "Mozilla/5.0 (Linux; U; Android 2.3.3; zh-cn; sdk Build/GRI34) AppleWebKit/533.1 (KHTML, like Gecko) Version/4.0 Mobile Safari/533.1 MicroMessenger/6.0.0.57_r870003.501 NetType/internet");

                     //获取状态吗

                     int code = conn.getResponseCode();

                     //判断状态吗

                     if(code ==200){

                         InputStream is = conn.getInputStream();

                         //使用工具类， 把字节输入流的数据编程字符串

                         String result = StreamTools.readStream(is);

                         Message msg = Message.obtain();//减少消息创建的数量

                         msg.obj = result;

                         msg.what = SUCCESS;

                         handler.sendMessage(msg);

                     }

                 } catch (Exception e) {

                     Message msg = Message.obtain();//减少消息创建的数量

                     msg.what = ERROR;

                     handler.sendMessage(msg);

                     e.printStackTrace();

                 }

             };

         }.start();

     }

 }

 package com.itheima.netsourceviewer.utils;

 import java.io.ByteArrayOutputStream;

 import java.io.IOException;

 import java.io.InputStream;

 /**

  * 流的工具类

  * @author Administrator

  *

  */

 public class StreamTools {

     /**

      * 把输入流的内容转换成字符串

      * @param is

      * @return null解析失败， string读取成功

      */

     public static String readStream(InputStream is) {

         try {

             ByteArrayOutputStream baos = new ByteArrayOutputStream();

             byte[] buffer = new byte[1024];

             int len = -1;

             while( (len = is.read(buffer))!=-1){

                 baos.write(buffer, 0, len);

             }

             is.close();

             String temptext = new String(baos.toByteArray());

             if(temptext.contains("charset=gb2312")){//解析meta标签

                 return new String(baos.toByteArray(),"gb2312");

             }else{

                 return new String(baos.toByteArray(),"utf-8");

             }

         } catch (IOException e) {

             e.printStackTrace();

             return null;

         }

     }

 }