Android学习笔记：利用httpclient和AsyncTask 发起网络http post操作 - 51kata - 博客园

来源： Android学习笔记：利用httpclient和AsyncTask 发起网络http post操作 – 51kata – 博客园

1、在Android4中，发起网络http操作，不能在Activity的事件（即主线程）中进行，必须在单独的线程中操作。

另外进行网络操作，需要在manifest文件中增加如下的权限：

<uses-permission Android:name=”android.permission.INTERNET” />

2、下面给出代码事例

    public void loadData() {
        new AsyncTask<String, Void, String>() {
            @Override
            protected String doInBackground(String... paramsInput) {
                String url = "http://10.0.0.5:8080/examples/action";
                List<NameValuePair> params = new ArrayList<NameValuePair>();
                params.add(new BasicNameValuePair("type", paramsInput[0]));
                params.add(new BasicNameValuePair("id", paramsInput[1]));
                /* 建立HTTPPost对象 */
                HttpPost httpRequest = new HttpPost(url);
 
                String strResult = "doPostError";
                try {
                    HttpClient httpClient = getHttpClient();
                    /* 添加请求参数到请求对象 */
                    httpRequest.setEntity(new UrlEncodedFormEntity(params,
                            HTTP.UTF_8));
                    /* 发送请求并等待响应 */
                    HttpResponse httpResponse = httpClient.execute(httpRequest);
                    /* 若状态码为200 ok */
                    if (httpResponse.getStatusLine().getStatusCode() == 200) {
                        /* 读返回数据 */
                        strResult = EntityUtils.toString(httpResponse
                                .getEntity());
 
                    } else {
                        strResult = "Error Response: "
                                + httpResponse.getStatusLine().toString();
                    }
                } catch (ClientProtocolException e) {
                    strResult = "Error Response: " + e.getMessage().toString();
                    e.printStackTrace();
                } catch (IOException e) {
                    strResult = "Error Response: " + e.getMessage().toString();
                    e.printStackTrace();
                } catch (Exception e) {
                    strResult = "Error Response: " + e.getMessage().toString();
                    e.printStackTrace();
                }
                return strResult;
            }
 
            @Override
            protected void onPostExecute(String result) {
                TextView view = (TextView) findViewById(R.id.resultText);
                view.setText(result);
                super.onPostExecute(result);
            }
 
        }.execute("query","1");
    }
 
private HttpClient getHttpClient() {
 
        // 创建 HttpParams 以用来设置 HTTP 参数（这一部分不是必需的）
 
        HttpParams httpParams = new BasicHttpParams();
 
        // 设置连接超时和 Socket 超时，以及 Socket 缓存大小
 
        HttpConnectionParams.setConnectionTimeout(httpParams, 20 * 1000);
 
        HttpConnectionParams.setSoTimeout(httpParams, 20 * 1000);
 
        HttpConnectionParams.setSocketBufferSize(httpParams, 8192);
 
        // 设置重定向，缺省为 true
 
        HttpClientParams.setRedirecting(httpParams, true);
 
        // 设置 user agent
 
        String userAgent = "Mozilla/5.0 (Windows; U; Windows NT 5.1; zh-CN; rv:1.9.2) Gecko/20100115 Firefox/3.6";
        HttpProtocolParams.setUserAgent(httpParams, userAgent);
 
        // 创建一个 HttpClient 实例
 
        // 注意 HttpClient httpClient = new HttpClient(); 是Commons HttpClient
 
        // 中的用法，在 Android 1.5 中我们需要使用 Apache 的缺省实现 DefaultHttpClient
 
        HttpClient httpClient = new DefaultHttpClient(httpParams);
 
        return httpClient;
    }