如何解决Android 不断尝试 POST 直到它通过
我有一条 POST 消息,在特定情况下我绝对必须在 Android 上发送,以至于我希望它继续尝试直到完成。我了解该设置:
urlConnection.setConnectTimeout(0);
会继续尝试连接直到它通过,但实际发生的是 try 块失败,而是抛出 UnkNownHostException:
private class SenDalert extends AsyncTask<String,String,String> {
protected String doInBackground(String... strings) {
Log.d(TAG,"sendAlarm: sending alarm");
String stringUrl = createUri();
HttpsURLConnection urlConnection = null;
BufferedReader reader = null;
String postData = "";
Log.d(TAG,"sendAlarm: apikey: " + apiKey);
try{
Log.d(TAG,"sendAlarm: trying");
URL finalURL = new URL(stringUrl);
urlConnection = (HttpsURLConnection)finalURL.openConnection();
urlConnection.setReadTimeout(10000);
urlConnection.setConnectTimeout(0);
urlConnection.setRequestProperty("Content-Type","application/json;charset=UTF-8");
urlConnection.setRequestProperty("Accept","application/json");
urlConnection.setRequestProperty("x-api-key",apiKey);
urlConnection.setRequestMethod("POST");
urlConnection.setDoInput(true);
urlConnection.setDoOutput(true);
int responseCode = urlConnection.getResponseCode();
Log.d(TAG,"doInBackground: response code = " + responseCode);
}catch (MalformedURLException e) {
e.printstacktrace();
Log.d(TAG,"doInBackground: error 1 " + e.toString());
}catch(UnkNownHostException e){
Log.d(TAG,"doInBackground: e: " + e);
Log.d(TAG,"doInBackground: retrying");
}
catch(Exception e){
Log.d(TAG,"doInBackground: error 2 " + e.toString());
}
想知道在 Android 上设置帖子消息的最佳方法是什么,即使手机处于飞行模式 5 小时,也要继续尝试连接直到连接成功。
编辑:下面@user3252344的回答,直接在AyncTask的catch块中再次调用该函数有什么问题:
catch(UnkNownHostException e){
Log.d(TAG,"doInBackground: retrying");
SendAlarm sendAlarm = new SendAlarm;
sendAlarm.execute();
}
解决方法
将连接超时设置为 0 意味着它不会超时,但如果连接失败,它仍然不会处理它。我猜你会收到一个 UnknownHostException
,因为它无法解析 url,因为它无法访问 DNS 服务器。
我建议你设置一个合理的连接超时,如果超时异常发生并重新运行。
final int READ_TIMEOUT = 500; // Timeout
final int RETRY_MS = 2000; //Retry every 2 seconds
final Handler handler = new Handler();
Runnable myUrlCall = () -> {
try {
//Make things
urlConnect.setReadTimeout(READ_TIMEOUT);
//Make the URL call,do response
} catch (SocketTimeoutException e) {
handler.postDelayed(myUrlCall,RETRY_MS);
} catch (/* other unintended errors*/ e) {
//Log the error or alert the user
}
};
handler.post(myUrlCall);
可能更好的主意:在您拨打电话之前使用 Android 设置检查是否有互联网。如果没有互联网,请使用更长的延迟。 Something like this would be the code you're looking for。
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