Android中網絡通信的幾種方式

Android網絡編程分爲兩種：基於http協議的，和基於socket的。
基於Http協議：HttpClient、HttpURLConnection、AsyncHttpClient框架等
基於Socket：
（1）針對TCP/IP的Socket、ServerSocket
（2）針對UDP/IP的DatagramSocket、DatagramPackage
（3）Apache Mina框架

一、HttpURLConnection的實現方式

String response = null;
Url url = new URL(path);
HttpURLConnection connection = (HttpURLConnection) url.openConnection(); // 新建連接實例
connection.setConnectTimeout(20000);// 設置連接超時時間，單位毫秒
//connection.setReadTimeout(20000);// 設置讀取數據超時時間，單位毫秒
connection.setDoInput(true);// 是否打開輸入流 true|false
connection.setRequestMethod("POST");// 提交方法POST|GET
//connection.setUseCaches(false);// 是否緩存true|false
//connection.setRequestProperty("accept", "*/*");
//connection.setRequestProperty("Connection", "Keep-Alive");
//connection.setRequestProperty("Charset", "UTF-8");
//connection.setRequestProperty("Content-Length", String.valueOf(data.length));
//connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
connection.connect();// 打開連接端口
int responseCode = conn.getResponseCode();
BufferedReader reader = null;
if (responseCode == 200) {
	reader = new BufferedReader(new InputStreamReader(connection.getInputStream(), "utf-8"));
	StringBuffer buffer = new StringBuffer();
	String line = "";
	while ((line = reader.readLine()) != null) {
		buffer.append(line);
	}
	response = buffer.toString();
} else {
	response = "返回碼："+responseCode;
}
reader.close();
conn.disconnect();

二、HttpClient實現方式

HttpResponse mHttpResponse = null;
HttpEntity mHttpEntity = null;
//創建HttpPost對象
//HttpPost httppost = new HttpPost(path);
//設置httpPost請求參數
//httppost.setEntity(new UrlEncodedFormEntity(params,HTTP.UTF_8));
HttpGet httpGet = new HttpGet(path);   
HttpClient httpClient = new DefaultHttpClient();
InputStream inputStream = null;
BufferedReader bufReader = null;
String result = "";
// 發送請求並獲得響應對象
mHttpResponse = httpClient.execute(httpGet);//如果是“POST”方式就傳httppost	
if (mHttpResponse.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
	// 獲得響應的消息實體
	mHttpEntity = mHttpResponse.getEntity();
	// 獲取一個輸入流
	inputStream = mHttpEntity.getContent();
	bufReader = new BufferedReader(new InputStreamReader(inputStream));	
	String line = "";
	while (null != (line = bufReader.readLine())) {
		result += line;
	}
	//result = EntityUtils.toString(mHttpResponse.getEntity());
} 
if (inputStream != null) {
	inputStream.close();
}
bufReader.close();
if (httpClient != null) {
	httpClient.getConnectionManager().shutdown();
}

三、實用AsyncHttpClient框架的實現方式：

AsyncHttpClient client = new AsyncHttpClient();  
client.get(url, new AsyncHttpResponseHandler() {  
	@Override  
	public void onSuccess(int i, Header[] headers, byte[] bytes) {  			
		String response = new String(bytes, 0, bytes.length, "UTF-8");  				   
	}  
	@Override  
	public void onFailure(int i, Header[] headers, byte[] bytes, Throwable throwable) {  

	}  
}); 

四、使用WebView視圖組件顯示網頁。

myWebView.getSettings().setJavaScriptEnabled(true);  
myWebView.setWebViewClient(new WebViewClient() {  
	@Override  
	public boolean shouldOverrideUrlLoading(WebView view, String url) {  
		view.loadUrl(url);  
		return true;  
	}  
});  
myWebView.loadUrl("http://"+networkAddress);  

小提示：

對於HttpClient和HttpURLConnection我們該怎麼選擇呢？

在Android 2.2版本之前，由於HttpClient有較少的bug，因此我們選擇它來使用。然而在Android 2.3版本及以後，HttpURLConnection則是最佳的選擇。HttpUrlConnection對大部分工作進行了包裝，屏蔽了不需要的細節，體積較小，因而非常適用於Android項目。並且HttpUrlConnection直接在系統層面做了緩存策略處理，可以加快重複請求的速度。由於其壓縮（GZip）和緩存機制可以有效地減少網絡訪問的流量，在提升速度和省電方面也起到了較大的作用。對於新的應用程序應該更加偏向於使用HttpURLConnection，因爲在後續Google官方會將更多的時間放在優化HttpURLConnection上面。