Android中提供的HttpURLConnection和HttpClient接口可以用來開發HTTP程序。以下是本人在學習中的總結與歸納。
1. HttpURLConnection接口
首先需要明確的是,Http通信中的POST和GET請求方式的不同。GET可以獲得靜態頁面,也可以把參數放在URL字符串後面,傳遞給服務器。而POST方法的參數是放在Http請求中。因此,在編程之前,應當首先明確使用的請求方法,然後再根據所使用的方式選擇相應的編程方式。
HttpURLConnection是繼承於URLConnection類,二者都是抽象類。其對象主要通過URL的openConnection方法獲得。創建方法如下代碼所示:
URL url = new URL("http://www.51cto.com/index.jsp?par=123456"); HttpURLConnection urlConn=(HttpURLConnection)url.openConnection();
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通過以下方法可以對請求的屬性進行一些設置,如下所示:
urlConn.setDoOutput(true); urlConn.setDoInput(true);
urlConn.setRequestMethod("POST");
urlConn.setUseCaches(false);
urlConn.disConnection();
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HttpURLConnection默認使用GET方式,例如下面代碼所示:
HttpURLConnection urlConn = (HttpURLConnection) url.openConnection();
InputStreamReader in = new InputStreamReader(urlConn.getInputStream());
BufferedReader buffer = new BufferedReader(in); String inputLine = null;
while (((inputLine = buffer.readLine()) != null)) {
resultData += inputLine + "\n"; }
in.close();
urlConn.disconnect();
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如果需要使用POST方式,則需要setRequestMethod設置。代碼如下:
String httpUrl = "http://192.168.1.110:8080/httpget.jsp";
String resultData = ""; URL url = null; try {
url = new URL(httpUrl); } catch (MalformedURLException e) { Log.e(DEBUG_TAG, "MalformedURLException"); } if (url != null) { try {
HttpURLConnection urlConn = (HttpURLConnection) url.openConnection();
urlConn.setDoOutput(true); urlConn.setDoInput(true);
urlConn.setRequestMethod("POST");
urlConn.setUseCaches(false); urlConn.setInstanceFollowRedirects(true);
urlConn.setRequestProperty("Content-Type","application/x-www-form-urlencoded");
urlConn.connect();
DataOutputStream out = new DataOutputStream(urlConn.getOutputStream());
String content = "par=" + URLEncoder.encode("ABCDEFG", "gb2312");
out.writeBytes(content);
out.flush(); out.close();
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2. HttpClient接口
使用Apache提供的HttpClient接口同樣可以進行HTTP操作。 對於GET和POST請求方法的操作有所不同。GET方法的操作代碼示例如下:
String httpUrl = "http://192.168.1.110:8080/httpget.jsp?par=HttpClient_android_Get";
HttpGet httpRequest = new HttpGet(httpUrl);
HttpClient httpclient = new DefaultHttpClient();
HttpResponse httpResponse = httpclient.execute(httpRequest);
if (httpResponse.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
String strResult = EntityUtils.toString(httpResponse.getEntity()); mTextView.setText(strResult); } else { mTextView.setText("請求錯誤!"); } }
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使用POST方法進行參數傳遞時,需要使用NameValuePair來保存要傳遞的參數。,另外,還需要設置所使用的字符集。代碼如下所示:
String httpUrl = "http://192.168.1.110:8080/httpget.jsp";
HttpPost httpRequest = new HttpPost(httpUrl);
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("par", "HttpClient_android_Post"));
HttpEntity httpentity = new UrlEncodedFormEntity(params, "gb2312");
httpRequest.setEntity(httpentity);
HttpClient httpclient = new DefaultHttpClient();
HttpResponse httpResponse = httpclient.execute(httpRequest);
if (httpResponse.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
String strResult = EntityUtils.toString(httpResponse.getEntity()); mTextView.setText(strResult); } else { mTextView.setText("請求錯誤!"); } }
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HttpClient實際上是對Java提供方法的一些封裝,在HttpURLConnection中的輸入輸出流操作,在這個接口中被統一封裝成了HttpPost(HttpGet)和HttpResponse,這樣,就減少了操作的繁瑣性。
另外,在使用POST方式進行傳輸時,需要進行字符編碼。
本文出自 “我的Android開發志” 博客,請務必保留此出處http://52android.blog.51cto.com/2554429/496621