Android手机开发：网络连接-打开Url下载信息

1. 简单版本

/** * 根据URL下载文件，前提是这个文件当中的内容是文本，函数的返回值就是文件当中的内容 1.创建一个URL对象 * 2.通过URL对象，创建一个HttpURLConnection对象 3.得到InputStram 4.从InputStream当中读取数据 *  * @param urlStr * @return */public String getTextFromUrl(String urlStr) {StringBuffer sb = new StringBuffer();String line = null;BufferedReader buffer = null;try {// 创建一个URL对象url = new URL(urlStr);// 创建一个Http连接HttpURLConnection urlConn = (HttpURLConnection) url.openConnection();// 使用IO流读取数据buffer = new BufferedReader(new InputStreamReader(urlConn.getInputStream()));while ((line = buffer.readLine()) != null) {sb.append(line);}} catch (Exception e) {e.printStackTrace();} finally {try {buffer.close();} catch (Exception e) {e.printStackTrace();}}return sb.toString();}

2. 发送http信息，并信息进行编码

//发送http信息，并信息进行编码public String SendDataPost(String url, String post)    {// 判断网络链接是否正常if (isNetworkAvailable(fromcon)) {try{StringmString = new String(post.getBytes(), "UTF-8");URL iurl = new URL(url);//直接提交地址，不要带参数        HttpURLConnection objConn = (HttpURLConnection)iurl.openConnection();//objConn.setRequestProperty("Cookie",HttpTools.PublishCookies());           objConn.setDoOutput(true);objConn.setDoInput(true);objConn.setRequestProperty("Content-type","application/x-www-form-urlencoded");objConn.setRequestMethod("POST");objConn.setRequestProperty("Content-Length",String.valueOf(mString.toCharArray().length));objConn.setConnectTimeout(30000);            objConn.setReadTimeout(30000);            objConn.connect();            OutputStream  objSM = objConn.getOutputStream();            OutputStreamWriter objSW = new OutputStreamWriter(objSM);            BufferedWriter  out = new BufferedWriter(objSW);                                   out.write(mString.toCharArray(),0,mString.toCharArray().length);            out.flush();            out.close();                        InputStream objSMP = objConn.getInputStream();            InputStreamReader objSRP = new InputStreamReader(objSMP, "utf-8");            BufferedReader in = new BufferedReader(objSRP);              String line = null;              StringBuilder sb = new StringBuilder();              while ((line = in.readLine()) != null) {                sb.append(line);              }              in.close();             String resp = sb.toString();            objSMP.close();            objConn.disconnect();            return resp;}catch (Exception ex) {        Log.i("CCCC", ex.toString());            return "";        }}else{Intent intent0 = new Intent(fromcon,LoginActivity.class);intent0.putExtra("msg","您当前网络连接已禁用，请重新设置!");fromcon.startActivity(intent0);return "";}    }// 判断网络是否正常public static boolean isNetworkAvailable(Context context) {ConnectivityManager connectivity = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);if (connectivity == null) {return false;} else {NetworkInfo info = connectivity.getActiveNetworkInfo();if (info == null) {return false;} else {if (info.isAvailable()) {return true;}}}return false;}