Android访问WCF(下篇)客户端开发

 

本章目的: 实现在Android客户端请求我们上篇建立的WCF数据服务.

此部分分为 建立Http请求 跟 接受WCF 返回的数据.

一. 建立Http请求的方法

protected String getRequest(String url, DefaultHttpClient client) throws Exception { String result = null; int statusCode = 0; HttpGet getMethod = new HttpGet(url); Log.d(TAG, "do the getRequest,url=" + url + ""); try { getMethod.setHeader("User-Agent", USER_AGENT); // HttpParams params = new HttpParams(); // 添加用户密码验证信息 // client.getCredentialsProvider().setCredentials( // new AuthScope(null, -1), // new UsernamePasswordCredentials(mUsername, mPassword)); HttpResponse httpResponse = client.execute(getMethod); // statusCode == 200 正常 statusCode = httpResponse.getStatusLine().getStatusCode(); Log.d(TAG, "statuscode = " + statusCode); // 处理返回的httpResponse信息 result = retrieveInputStream(httpResponse.getEntity()); } catch (Exception e) { Log.e(TAG, e.getMessage()); throw new Exception(e); } finally { getMethod.abort(); } return result; }

 

参数URL: 我们要请求的地址

Client:  这个可以直接用new DefaultHttpClient(new BasicHttpParams()) 来初始化.

这个方法中需要注意RetrieveInputStream方法, 这个是当Http请求完成之后, 用来处理服务器返回数据的方法,

二. 接受从WCF端传回的数据

protected String retrieveInputStream(HttpEntity httpEntity) { int length = (int) httpEntity.getContentLength(); if (length < 0) length = 10000; StringBuffer stringBuffer = new StringBuffer(length); try { InputStreamReader inputStreamReader = new InputStreamReader( httpEntity.getContent(), HTTP.UTF_8); char buffer[] = new char[length]; int count; while ((count = inputStreamReader.read(buffer, 0, length - 1)) > 0) { stringBuffer.append(buffer, 0, count); } } catch (UnsupportedEncodingException e) { Log.e(TAG, e.getMessage()); } catch (IllegalStateException e) { Log.e(TAG, e.getMessage()); } catch (IOException e) { Log.e(TAG, e.getMessage()); } return stringBuffer.toString(); }

 

此方法在接受到WCF服务端返回的数据之后,  转换程String类型返回.

附加内容:

private static final String BASE_URL = "http://10.0.2.2:82/BlogCategoryService/"; private static final String EXTENSION = "Json/";; private static final String TAG = "API"; private static final String USER_AGENT = "Mozilla/4.5"; public JSONObject getObject(String sbj) throws JSONException, Exception { return new JSONObject(getRequest(BASE_URL + EXTENSION + sbj)); } public JSONArray getArray(String sbj) throws JSONException, Exception { return new JSONArray(getRequest(BASE_URL + EXTENSION + sbj)); } protected String getRequest(String url) throws Exception { return getRequest(url, new DefaultHttpClient(new BasicHttpParams())); }

 

请求数据之前封装方法:

总结 ： 此篇主要说明了Http请求的的两个阶段, 建立请求跟接受服务器返回的数据, 在下篇再主要说明如何处理服务端返回的JSON数据,并把数据显示在UI上面.