Android 通过http访问服务器

目前Android 与服务器交互有两种方式：1.Socket 2. Http ；

但由于Http的封装性以及性能比socket要好，所以推荐使用http方式和服务器交互；

通过http访问服务器有三种方法：1.post  2. get  3.或者上传文件

例子如下：

protected JSONObject toWebService(String url, String method,
                List<NameValuePair> params) {
            try {
                Log.w("HealthCareAPI", "toWebService: url = " + url);
                HttpUriRequest request = null;
                if (HealthCareApi.GET_METHOD.equalsIgnoreCase(method)) {  //Get方法
                    url = url + "?" + URLEncodedUtils.format(params, "UTF-8");
                    Log.w("HealthCareApiCore", url);
                    request = new HttpGet(url);
                } else if (HealthCareApi.POST_METHOD.equalsIgnoreCase(method)) {  //Post方法
                    HttpPost postRequest = new HttpPost(url);
                    UrlEncodedFormEntity entity = new UrlEncodedFormEntity(
                            params, HTTP.UTF_8);
                    postRequest.setHeader("Content-Type",
                            "application/x-www-form-urlencoded; charset=utf-8");
                    postRequest.setEntity(entity);
                    request = postRequest;
                } else if (HealthCareApi.POST_METHOD_WITH_BIN
                        .equalsIgnoreCase(method)) {   //上传文件，这里指的是上传图片文件
                    HttpPost postRequest = new HttpPost(url);
                    MultipartEntity multipartContent = new MultipartEntity();
                    for (NameValuePair nameValuePair : params) {
                        if (nameValuePair.getName().equals("photo")
                                || nameValuePair.getName().equals("pic")
                                || nameValuePair.getName().equals("photo_url")) {
                            File photoFile = new File(nameValuePair.getValue());
                            if (photoFile.exists()) {
                                String extensionName = HealthCareApi
                                        .getExtensionName(photoFile.getName());
                                FileBody fileBody = new FileBody(photoFile,
                                        MimeTypeMap.getSingleton()
                                                .getMimeTypeFromExtension(
                                                        new String(extensionName).toLowerCase()));
                                multipartContent.addPart(
                                        nameValuePair.getName(), fileBody);
                            }
                        } else {
                            multipartContent.addPart(nameValuePair.getName(),
                                    new StringBody(nameValuePair.getValue(),
                                            Charset.forName("UTF-8")));
                        }
                    }
                    postRequest.setEntity(multipartContent);
                    request = postRequest;
                }
                HttpParams httpParams = new BasicHttpParams();
                HttpConnectionParams
                        .setConnectionTimeout(httpParams, 20 * 1000);
                HttpConnectionParams.setSoTimeout(httpParams, 20 * 1000);
                HttpResponse httpResponse = new DefaultHttpClient(httpParams)
                        .execute(request);
                HttpEntity entity = httpResponse.getEntity();
                String res = EntityUtils.toString(entity, "UTF-8");
                Log.w("HealtCareApi", "res: " + res);
                JSONObject object = new JSONObject(res);
                return object;
            } catch (Exception e) {
                e.printStackTrace();
                mException = e;
            }
            return null;
        }