Android有两套http的API,刚开始使用网络编程时多少有些迷惑到底用哪个好呢?其实孰优孰劣无需再争论,google已经指出HttpUrlConnection是Android更优的选择,并在SDK文档中引用了博客(需要代理访问)http://android-developers.blogspot.com/2011/09/androids-http-clients.html来阐述各自的优缺点。国内也有些博客大致翻译了上面的内容,并对了一些测试,可惜测试不严密,某博客甚至得出HttpUrlConnection的下载速度快几倍的结论,其实并没有公平反映出二者的下载速度。
虽然我已经使用过HttpUrlConnection实现了一个轻量级http引擎用于下载,但是好奇心还是促使我写了一个测试程序用于比较二者的性能。由于HttpClient仅仅是一个接口,所以我选用了其实现类DefaultHttpClient和HttpUrlConnection做比较,方法很简单,分别下载同一个文件10次,然后计算耗时的平均值,测试代码片段如下:
@Override
public void onClick(View v)
{
if (v.equals(mTestHttpClientBtn))
{
new Thread(new Runnable()
{
@Override
public void run()
{
long averageTime = 0;
for (int i = 0; i < 10; i++)
{
File file = new File(getFilesDir(), String.valueOf(i) + ".file");
FileOutputStream fileOutputStream = null;
try
{
fileOutputStream = new FileOutputStream(file);
}
catch (FileNotFoundException e)
{
Log.e(TAG, "", e);
return;
} long startTime = System.currentTimeMillis();
testHttpClient(fileOutputStream);
long stopTime = System.currentTimeMillis(); averageTime += stopTime - startTime;
}
averageTime /= 10; // 测试完成
Message msg = new Message();
msg.what = MSG_TEST_HTTP_CLIENT_DONE;
msg.obj = averageTime;
mHandler.sendMessage(msg);
}
}).start(); return;
} if (v.equals(mTestHttpUrlConnectionBtn))
{
new Thread(new Runnable()
{
@Override
public void run()
{
long averageTime = 0;
for (int i = 0; i < 10; i++)
{
File file = new File(getFilesDir(), String.valueOf(i + 10) + ".file");
FileOutputStream fileOutputStream = null;
try
{
fileOutputStream = new FileOutputStream(file);
}
catch (FileNotFoundException e)
{
Log.e(TAG, "", e);
return;
} long startTime = System.currentTimeMillis();
testHttpUrlConnection(fileOutputStream);
long stopTime = System.currentTimeMillis(); averageTime += stopTime - startTime;
}
averageTime /= 10; // 测试完成
Message msg = new Message();
msg.what = MSG_TEST_HTTP_URL_CONNECTION_DONE;
msg.obj = averageTime;
mHandler.sendMessage(msg);
}
}).start(); return;
}
} private void testHttpClient(FileOutputStream fileOutputStream)
{
DefaultHttpClient httpClient = new DefaultHttpClient(); HttpEntity entity = null;
InputStream inputStream = null;
try
{
HttpGet httpGet = new HttpGet(TEST_URL);
HttpResponse httpResponse = httpClient.execute(httpGet); StatusLine statusLine = httpResponse.getStatusLine();
if (statusLine == null)
{
throw new Exception("no status line !!!");
}
int responseCode = statusLine.getStatusCode();
if (responseCode < 200 || responseCode >= 300)
{
throw new Exception("response error !!!");
}
entity = httpResponse.getEntity();
if (entity == null)
{
throw new Exception("no entity !!!");
}
inputStream = entity.getContent();
int bytesRead = -1;
byte[] buffer = new byte[4096];
while ((bytesRead = inputStream.read(buffer)) != -1)
{
fileOutputStream.write(buffer, 0, bytesRead);
}
}
catch (Exception e)
{
Log.e(TAG, "", e);
}
finally
{
try
{
if (inputStream != null)
{
inputStream.close();
} if (entity != null)
{
entity.consumeContent();
} if (fileOutputStream != null)
{
fileOutputStream.flush();
fileOutputStream.close();
}
}
catch (Exception e)
{
Log.e(TAG, "", e);
}
}
} private void testHttpUrlConnection(FileOutputStream fileOutputStream)
{
HttpURLConnection httpURLConnection = null;
InputStream inputStream = null;
try
{
httpURLConnection = (HttpURLConnection) new URL(TEST_URL).openConnection();
httpURLConnection.setRequestMethod("GET");
httpURLConnection.connect(); int responseCode = httpURLConnection.getResponseCode();
if (responseCode < 200 || responseCode >= 300)
{
throw new Exception("response error !!!");
}
inputStream = httpURLConnection.getInputStream();
int bytesRead = -1;
byte[] buffer = new byte[4096];
while ((bytesRead = inputStream.read(buffer)) != -1)
{
fileOutputStream.write(buffer, 0, bytesRead);
}
}
catch (Exception e)
{
Log.e(TAG, "", e);
}
finally
{
try
{
if (inputStream != null)
{
inputStream.close();
} if (httpURLConnection != null)
{
httpURLConnection.disconnect();
} if (fileOutputStream != null)
{
fileOutputStream.flush();
fileOutputStream.close();
}
}
catch (Exception e)
{
Log.e(TAG, "", e);
}
}
}
测试结果如下:
下载文件:360MobileSafe_4.3.5beta.apk 链接:http://msoftdl.360.cn/mobilesafe/shouji360/360safesis/360MobileSafe_4.3.5beta.apk 大小:12.65MB
测试结果: DefaultHttpClient平均耗时:7275ms(第一次) 3861ms(第二次) HttpURLConnection平均耗时:5445ms(第一次) 3119ms(第二次)
HttpURLConnection传输效率更高
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
下载文件:old offender.apk 链接:http://gdown.baidu.com/data/wisegame/79fb2f638cc11043/oldoffender.apk 大小:4.98MB
测试结果: DefaultHttpClient平均耗时:3780ms(第一次) 4008ms(第二次) 4209ms(第三次) HttpURLConnection平均耗时:3718ms(第一次) 4783ms(第二次) 3945ms(第三次)
二者相差无几
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
下载文件:baidu首页html 链接:http://www.baidu.com 大小:使用DefaultHttpClient下载的是11.61KB的html(被baidu视为PC端浏览器访问),使用HttpURLConnection下载的是5.22KB的html(被baidu视为移动端浏览器访问)
测试结果:无效
说明:这也是某些测试说HttpUrlConnection下载速度快几倍所使用的链接,其实根本原因在于这两API下载的html大小就差了两倍,比较结果是不公平的
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
下载文件:baidu首页logo 链接:http://www.baidu.com/img/bdlogo.gif 大小:1.54KB
测试结果:无效
说明:由于文件较小,有时候DefaultHttpClient比HttpURLConnection快很多,而下一秒的测试结果又反过来了,这是因为传输时间相差无几,而连接的耗时不确定,从而导致总耗时相差很大,所以无法判断谁的传输效率更高。
结论:文件越大,可能HttpUrlConnection的速度优势越明显,应该是SDK文档宣称的GZIP压缩传输导致传输时间缩短的原因,当然,前提是服务器得支持GZIP传输~