环境搭建：

本地服务器(下载wamp【Windows, Apache, MySQL, PHP 】，安装即可，然后将网页或文件放进 www directory)

虚拟机(访问本地服务器的ip：10.0.2.2)

注意事项：

权限相关

网络访问 存储卡访问

文件权限 如：chmod  777 /data

源代码：

package com.example.net_ex04;

import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import org.apache.http.HttpEntity;

import org.apache.http.HttpResponse;

import org.apache.http.client.ClientProtocolException;

import org.apache.http.client.HttpClient;

import org.apache.http.client.methods.HttpGet;

import org.apache.http.impl.client.DefaultHttpClient;

import android.os.AsyncTask;

import android.os.Bundle;

import android.os.Environment;

import android.app.Activity;

import android.view.Menu;

import android.view.View;

import android.widget.Button;

import android.widget.ProgressBar;

public class MainActivity extends Activity {

ProgressBar progressBar;

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

progressBar = (ProgressBar)this.findViewById(R.id.progressBar1);

Button button = (Button)this.findViewById(R.id.button1);

button.setOnClickListener(new View.OnClickListener() {

String url = "http://10.0.2.2/Music.flv";

@Override

public void onClick(View v) {

// TODO Auto-generated method stub

progressBar.setVisibility(View.VISIBLE);

progressBar.setProgress(0);

new DownloadTask().execute(url);

}

});

}

@Override

public boolean onCreateOptionsMenu(Menu menu) {

getMenuInflater().inflate(R.menu.activity_main, menu);

return true;

}

class DownloadTask extends AsyncTask{

public DownloadTask() {

// TODO Auto-generated constructor stub

}

@Override

protected String doInBackground(String... params) {

// TODO Auto-generated method stub

HttpGet httpRequest = new HttpGet(params[0]);

HttpClient httpClient = new DefaultHttpClient();

try{

HttpResponse httpResponse = httpClient.execute(httpRequest);

HttpEntity entity = httpResponse.getEntity();

long length = entity.getContentLength();

progressBar.setMax((int)length);

InputStream inputStream = entity.getContent();

byte[] b = new byte[1024];

int readedLength = -1;

//File file = new File(Environment.getExternalStorageDirectory().getAbsoluteFile(), "Music.flv");

File file = new File("/data/Music.flv");

if(!file.exists())

{

file.createNewFile();

}

OutputStream outputStream = new FileOutputStream(file);

int count = 0;

while((readedLength = inputStream.read(b)) != -1){

outputStream.write(b, 0, readedLength);

count += readedLength;

publishProgress(count);

}

}catch(ClientProtocolException e){

e.printStackTrace();

}catch(IOException e){

e.printStackTrace();

}

return null;

}

protected void onProgressUpdate(Integer... values){

progressBar.setProgress(values[0]);

super.onProgressUpdate(values);

}

}

}