获取网络源码

package com.itheima.viewpagesource;

import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

import com.itheima.viewpagesource.utils.StreamTool;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.text.TextUtils;
import android.view.View;
import android.webkit.URLUtil;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {

    protected static final int SUCCESS = 0;
    protected static final int ERROR = 1;
    protected static final int NETWORK_ERROR = 2;


    private EditText ed_path;
    private TextView tv;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ed_path = (EditText) findViewById(R.id.ed_path);
        tv = (TextView) findViewById(R.id.tv);
    }

    //定义一个秘书
    Handler handler = new Handler(){
        
        public void handleMessage(android.os.Message msg) {
            
            switch (msg.what) {
            case SUCCESS:
                
                String value = (String) msg.obj;
                tv.setText(value);
                break;
            case ERROR:
                System.out.println("ERROR ==============");
                Toast.makeText(MainActivity.this, "错误发生了  ..  ERROR", 0).show();
                
                break;
            case NETWORK_ERROR:
                System.out.println("NETWORK_ERROR  ==============");
                Toast.makeText(MainActivity.this, "错误发生了  ..  NETWORK_ERROR ", 0).show();
                
                
                break;

            default:
                break;
            }
        };
    };
    
    
    String path = null;
    public void viewPageSource(View v){
        
        path = ed_path.getText().toString().trim();
        
        if(TextUtils.isEmpty(path)){
            Toast.makeText(this, "路径有错误...", 0).show();
            return;
        }
        
        //连接网络  , 要启动一个新的线程去  干 耗时的事儿
        new Thread(){
            public void run() {
                
                try {
                    URL url = new URL(path);
                    HttpURLConnection conn = (HttpURLConnection) url.openConnection();
                    
                    //设置连接超时为 5 秒钟
                    conn.setConnectTimeout(5000);
                    conn.setRequestMethod("GET");
                    
                    // User-Agent: Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.2; WOW64; Trident/6.0)
                    //通过 设置 user-agent http的请求头 , 来骗  网站, 返回  pc机上 使用 浏览器 返回 数据的一个 页面 源代码
                    
                    conn.setRequestProperty("User-Agent", "Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.2; WOW64; Trident/6.0)");
                    
                    String contentType = conn.getContentType();
                    
                    int code = conn.getResponseCode();
                    if(code==200){
                        
                        InputStream in = conn.getInputStream();
                        
                        // BitFactory.decodeStream(in)
                        //如何一个将一个 流转换为 字符串 
                        
                        //这里的data是从  服务器 返回的
                        String data = StreamTool.decodeStream(in);
                        
                        // 展示的屏幕上 
                        Message msg = Message.obtain();
                        msg.what =SUCCESS;
                        msg.obj = data;
                        
                        handler.sendMessage(msg);
                    }else{
                        
                        Message msg = Message.obtain();
                        msg.what =ERROR;
                        
                        handler.sendMessage(msg);
                        
                    }
                    
                } catch (Exception e) {
                    e.printStackTrace();
                    
                    Message msg = Message.obtain();
                    msg.what =NETWORK_ERROR;
                    
                    handler.sendMessage(msg);
                }
                
                
            };
        }.start();
        
    }
    
    
}

package com.itheima.viewpagesource.utils;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;

public class StreamTool {

    public static String decodeStream(InputStream in) throws IOException {
        
        // 底层流
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        
        int len =0;
        byte[] buf = new byte[1024];
        
        while((len=in.read(buf))>0){
            baos.write(buf, 0, len);
        }
        
        String data = baos.toString();
        
        return data;
    }

}