Android HttpURLConnection网络连接

public static String post(String path, Map<String, Object> params) throws Exception
{
    Log.v("params", path + " ---- " + params.toString());
    URL url = new URL(path);

    PrintWriter printWriter = null;
    BufferedReader bufferedReader = null;
    StringBuffer responseResult = null;
    StringBuffer paramsStringBuffer = new StringBuffer();

    // 组织请求参数
    Iterator it = params.entrySet().iterator();
    while (it.hasNext()) {
        Map.Entry element = (Map.Entry) it.next();
        paramsStringBuffer.append(element.getKey());
        paramsStringBuffer.append("=");
        paramsStringBuffer.append(URLEncoder.encode((String) element.getValue(), "UTF-8"));
        paramsStringBuffer.append("&");
    }

    HttpURLConnection conn = (HttpURLConnection) url.openConnection();
    conn.setRequestMethod("POST");
    // 发送POST请求必须设置如下两行
    conn.setDoOutput(true);
    conn.setDoInput(true);
    // 设置通用的请求属性
    conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded;charset=utf-8");
    conn.setRequestProperty("Content-Length", String.valueOf(paramsStringBuffer.length()));
    conn.setRequestProperty("Accept-Charset", "utf-8");
    conn.setRequestProperty("contentType", "utf-8");
    conn.setUseCaches(false);
    conn.setInstanceFollowRedirects(true);

    // 获取URLConnection对象对应的输出流
    printWriter = new PrintWriter(conn.getOutputStream());
    // 发送请求参数
    printWriter.write(paramsStringBuffer.toString());
    // flush输出流的缓冲
    printWriter.flush();

    int responseCode = conn.getResponseCode();
    if (responseCode == HttpURLConnection.HTTP_OK)
    {
        // 定义BufferedReader输入流来读取URL的ResponseData
        bufferedReader = new BufferedReader(new InputStreamReader(
                conn.getInputStream()));
        String line;
        responseResult = new StringBuffer();
        while ((line = bufferedReader.readLine()) != null) {
            responseResult.append(line);
        }

    }

    if (printWriter != null) {
        printWriter.close();
    }
    if (bufferedReader != null) {
        bufferedReader.close();
    }
    conn.disconnect();

    if(responseResult != null)
    {
        Log.v("resultString", path + " ---- " + responseResult.toString());
        return responseResult.toString();
    }
    else
    {
        return null;
    }
}

Map<String, Object> params = new HashMap<String, Object>();
        params.put("pcode", area.pcode);
resultString = UrlConnectionUtil.post("server url", params);

public static String get(String path)
{
    try {
        URL url = new URL(path.trim());
        StringBuffer responseResult = null;

        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setRequestMethod("GET");

        // 设置通用的请求属性
        conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded;charset=utf-8");
        conn.setRequestProperty("Accept-Charset", "utf-8");
        conn.setRequestProperty("contentType", "utf-8");

        conn.connect();

        BufferedReader reader = new BufferedReader(new InputStreamReader(
                conn.getInputStream()));
        String line;
        responseResult = new StringBuffer();
        while ((line = reader.readLine()) != null) {
            responseResult.append(line);
        }
        reader.close();
        conn.disconnect();

        if(responseResult != null)
        {
            return responseResult.toString();
        }
        else
        {
            return null;
        }
    }catch (Exception e) {
        e.printStackTrace();
        return null;
    }
}

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.brand.aaa">
    <uses-permission android:name="android.permission.INTERNET" />
    ...