Gestire la risposta del server in Android
https://stackoverflow.com/questions/8381896
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28-10-2019 - |
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Nella mia applicazione sto recuperando i dati utilizzando WebServices. Ma quando il server è inattivo o meno in stato attivo, fornisce il codice di risposta 500 e la mia forza applicativa si chiude.
Per favore guidami come gestire questa condizione nella mia applicazione. L'output di Logcat è mostrato di seguito:
12-05 12:17:22.337: V/response code(950): 500
12-05 12:17:22.347: W/System.err(950): org.json.JSONException: A JSONArray text must start with '[' at character 1 of <html>
12-05 12:17:22.347: W/System.err(950): <head>
12-05 12:17:22.347: W/System.err(950): <title>Configuration Error</title>
12-05 12:17:22.347: W/System.err(950): <style>
12-05 12:17:22.347: W/System.err(950): body {font-family:"Verdana";font-weight:normal;font-size: .7em;color:black;}
12-05 12:17:22.347: W/System.err(950): p {font-family:"Verdana";font-weight:normal;color:black;margin-top: -5px}
12-05 12:17:22.347: W/System.err(950): b {font-family:"Verdana";font-weight:bold;color:black;margin-top: -5px}
12-05 12:17:22.347: W/System.err(950): H1 { font-family:"Verdana";font-weight:normal;font-size:18pt;color:red }
12-05 12:17:22.347: W/System.err(950): H2 { font-family:"Verdana";font-weight:normal;font-size:14pt;color:maroon }
12-05 12:17:22.356: W/System.err(950): pre {font-family:"Lucida Console";font-size: .9em}
12-05 12:17:22.356: W/System.err(950): .marker {font-weight: bold; color: black;text-decoration: none;}
12-05 12:17:22.356: W/System.err(950): .version {color: gray;}
12-05 12:17:22.356: W/System.err(950): .error {margin-bottom: 10px;}
12-05 12:17:22.356: W/System.err(950): .expandable { text-decoration:underline; font-weight:bold; color:navy; cursor:hand; }
12-05 12:17:22.356: W/System.err(950): </style>
12-05 12:17:22.356: W/System.err(950): </head>
12-05 12:17:22.356: W/System.err(950):
12-05 12:17:22.356: W/System.err(950): <body bgcolor="white">
12-05 12:17:22.366: W/System.err(950):
12-05 12:17:22.366: W/System.err(950): <span><H1>Server Error in '/' Application.<hr width=100% size=1 color=silver></H1>
12-05 12:17:22.366: W/System.err(950):
12-05 12:17:22.366: W/System.err(950): <h2> <i>Configuration Error</i> </h2></span>
12-05 12:17:22.366: W/System.err(950):
12-05 12:17:22.366: W/System.err(950): <font face="Arial, Helvetica, Geneva, SunSans-Regular, sans-serif ">
12-05 12:17:22.366: W/System.err(950):
12-05 12:17:22.366: W/System.err(950): <b> Description: </b>An error occurred during the processing of a configuration file required to service this request. Please review the specific error details below and modify your configuration file appropriately.
12-05 12:17:22.377: W/System.err(950): <br><br>
12-05 12:17:22.377: W/System.err(950):
12-05 12:17:22.377: W/System.err(950): <b> Parser Error Message: </b>Unrecognized attribute 'targetFramework'. Note that attribute names are case-sensitive.<br><br>
12-05 12:17:22.377: W/System.err(950):
12-05 12:17:22.377: W/System.err(950): <b>Source Error:</b> <br><br>
12-05 12:17:22.377: W/System.err(950):
12-05 12:17:22.377: W/System.err(950): <table width=100% bgcolor="#ffffcc">
12-05 12:17:22.377: W/System.err(950): <tr>
12-05 12:17:22.377: W/System.err(950): <td>
12-05 12:17:22.377: W/System.err(950): <code><pre>
12-05 12:17:22.377: W/System.err(950):
12-05 12:17:22.377: W/System.err(950): Line 30: <error statusCode="404" redirect="filenotfound.htm" />
12-05 12:17:22.377: W/System.err(950): Line 31: </customErrors>
12-05 12:17:22.377: W/System.err(950): <font color=red>Line 32: <compilation debug="true" targetFramework="4.0">
12-05 12:17:22.396: W/System.err(950): </font>Line 33: <expressionBuilders>
12-05 12:17:22.396: W/System.err(950): Line 34: <add expressionPrefix="NopResources" type="NopSolutions.NopCommerce.BusinessLogic.Localization.NopResourceExpressionBuilder, Nop.BusinessLogic" /></pre></code>
12-05 12:17:22.396: W/System.err(950):
12-05 12:17:22.396: W/System.err(950): </td>
12-05 12:17:22.396: W/System.err(950): </tr>
12-05 12:17:22.396: W/System.err(950): </table>
12-05 12:17:22.396: W/System.err(950):
12-05 12:17:22.396: W/System.err(950): <br>
12-05 12:17:22.396: W/System.err(950):
12-05 12:17:22.396: W/System.err(950): <b> Source File: </b> C:\Websites\balajeebazaar\web.config<b> Line: </b> 32
12-05 12:17:22.396: W/System.err(950): <br><br>
12-05 12:17:22.396: W/System.err(950):
12-05 12:17:22.396: W/System.err(950): <hr width=100% size=1 color=silver>
12-05 12:17:22.407: W/System.err(950):
12-05 12:17:22.407: W/System.err(950): <b>Version Information:</b> Microsoft .NET Framework Version:2.0.50727.4963; ASP.NET Version:2.0.50727.4955
12-05 12:17:22.407: W/System.err(950):
12-05 12:17:22.407: W/System.err(950): </font>
12-05 12:17:22.407: W/System.err(950):
12-05 12:17:22.416: W/System.err(950): </body>
12-05 12:17:22.416: W/System.err(950): </html>
12-05 12:17:22.416: W/System.err(950): <!--
12-05 12:17:22.416: W/System.err(950): [ConfigurationErrorsException]: Unrecognized attribute 'targetFramework'. Note that attribute names are case-sensitive. (C:\Websites\balajeebazaar\web.config line 32)
12-05 12:17:22.416: W/System.err(950): at System.Web.HttpRuntime.HostingInit(HostingEnvironmentFlags hostingFlags)
12-05 12:17:22.416: W/System.err(950): [HttpException]: Unrecognized attribute 'targetFramework'. Note that attribute names are case-sensitive. (C:\Websites\balajeebazaar\web.config line 32)
12-05 12:17:22.416: W/System.err(950): at System.Web.HttpRuntime.FirstRequestInit(HttpContext context)
12-05 12:17:22.416: W/System.err(950): at System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context)
12-05 12:17:22.416: W/System.err(950): at System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context)
12-05 12:17:22.416: W/System.err(950): --><!--
12-05 12:17:22.426: W/System.err(950): This error page might contain sensitive information because ASP.NET is configured to show verbose error messages using <customErrors mode="Off"/>. Consider using <customErrors mode="On"/> or <customErrors mode="RemoteOnly"/> in production environments.-->
12-05 12:17:22.426: W/System.err(950): at org.json.JSONTokener.syntaxError(JSONTokener.java:448)
12-05 12:17:22.426: W/System.err(950): at org.json.JSONArray.<init>(JSONArray.java:104)
12-05 12:17:22.426: W/System.err(950): at org.json.JSONArray.<init>(JSONArray.java:150)
12-05 12:17:22.426: W/System.err(950): at cm.bzaar.CallWebservices.getCategory(CallWebservices.java:48)
12-05 12:17:22.426: W/System.err(950): at cm.bzaar.CategoryActivity$Loader.doInBackground(CategoryActivity.java:98)
12-05 12:17:22.426: W/System.err(950): at cm.bzaar.CategoryActivity$Loader.doInBackground(CategoryActivity.java:1)
12-05 12:17:22.436: W/System.err(950): at android.os.AsyncTask$2.call(AsyncTask.java:185)
12-05 12:17:22.436: W/System.err(950): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:256)
12-05 12:17:22.436: W/System.err(950): at java.util.concurrent.FutureTask.run(FutureTask.java:122)
12-05 12:17:22.436: W/System.err(950): at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:648)
12-05 12:17:22.436: W/System.err(950): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:673)
12-05 12:17:22.436: W/System.err(950): at java.lang.Thread.run(Thread.java:1060)
12-05 12:17:22.436: W/dalvikvm(950): threadid=17: thread exiting with uncaught exception (group=0x4001aa28)
12-05 12:17:22.446: E/AndroidRuntime(950): Uncaught handler: thread AsyncTask #1 exiting due to uncaught exception
12-05 12:17:22.446: E/AndroidRuntime(950): java.lang.RuntimeException: An error occured while executing doInBackground()
12-05 12:17:22.446: E/AndroidRuntime(950): at android.os.AsyncTask$3.done(AsyncTask.java:200)
12-05 12:17:22.446: E/AndroidRuntime(950): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:234)
12-05 12:17:22.446: E/AndroidRuntime(950): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:258)
12-05 12:17:22.446: E/AndroidRuntime(950): at java.util.concurrent.FutureTask.run(FutureTask.java:122)
12-05 12:17:22.446: E/AndroidRuntime(950): at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:648)
12-05 12:17:22.446: E/AndroidRuntime(950): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:673)
12-05 12:17:22.446: E/AndroidRuntime(950): at java.lang.Thread.run(Thread.java:1060)
12-05 12:17:22.446: E/AndroidRuntime(950): Caused by: java.lang.NullPointerException
12-05 12:17:22.446: E/AndroidRuntime(950): at cm.bzaar.CategoryActivity$Loader.doInBackground(CategoryActivity.java:100)
12-05 12:17:22.446: E/AndroidRuntime(950): at cm.bzaar.CategoryActivity$Loader.doInBackground(CategoryActivity.java:1)
12-05 12:17:22.446: E/AndroidRuntime(950): at android.os.AsyncTask$2.call(AsyncTask.java:185)
12-05 12:17:22.446: E/AndroidRuntime(950): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:256)
12-05 12:17:22.446: E/AndroidRuntime(950): ... 4 more
Vedi il codice seguente:
Segmento di codice in cui la funzione viene chiamata per chiamare WebService:
@Override
protected Void doInBackground(Void... arg0) {
CategoryArray = new JSONArray();
CategoryArray = CW
.getCategory("url");
for (int i = 0; i <= CategoryArray.length() - 1; i++) {
try {
Log.v("category array : ", CategoryArray.getString(i));
String[] val = CategoryArray.getString(i).split("•");
CategoryID.add(i, val[0]);
CategoryList.add(i, val[1]);
} catch (JSONException e) {
e.printStackTrace();
}
}
adapter = new CategoryListAdapter(CategoryActivity.this,
CategoryList);
return null;
}
funzione da chiamare WebService:
public JSONArray getCategory(String URL){
try {
HttpPost request = new HttpPost(URL);
request.setHeader("Accept", "application/json");
request.setHeader("Content-type", "application/json");
// Send request to WCF service
DefaultHttpClient httpClient1 = new DefaultHttpClient();
HttpResponse response = httpClient1.execute(request);
Log.v("response code", response.getStatusLine().getStatusCode()
+ "");
responseCode = response.getStatusLine().getStatusCode();
// if(responseCode > 200){ // HERE I WS TRYING TO BREAK THE CODE AND TRYING TO RETURN NULL BT UNABLE TO DO SO
// CategoryArray = new JSONArray();
// CategoryArray.put(false);
// return null;
// }else{
HttpEntity responseEntity = response.getEntity();
// Read response data into buffer
char[] buffer = new char[(int) responseEntity.getContentLength()];
InputStream stream = responseEntity.getContent();
InputStreamReader reader = new InputStreamReader(stream);
reader.read(buffer);
stream.close();
CategoryArray = new JSONArray(new String(buffer));
Log.v("results length : ", CategoryArray.length() + "");
// }
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
return CategoryArray;
}
Guarda la riga in cui sto confrontando il codice di risposta. Guidami su come posso rompere il mio codice lì e mostrare UA Toast su UI
Soluzione
Dopo aver visto il logcat che hai pubblicato, sento che stai recuperando una stringa JSON come risposta. Quando ottieni la risposta che desideri dovrai analizzarla.
Quindi, affinché non sei trattenuto in seguito nel tuo codice, ti sto aiutando a continuare dopo aver ottenuto la tua risposta fornendo il seguente esempio del mio:
In uno dei miei progetti la risposta che ho ricevuto dal servizio web è stata:
{"CheckRecord": [{"rollno": "ABC2", "Percentage": 40, "frequentato": 12, "mancata": 34}], "Table1": []}
Per analizzare ho fatto quanto segue:
JSONObject jsonobject = new JSONObject(result);
JSONArray array = jsonobject.getJSONArray("checkrecord");
int max = array.length();
for (int j = 0; j < max; j++)
{
JSONObject obj = array.getJSONObject(j);
JSONArray names = obj.names();
for (int k = 0; k < names.length(); k++)
{
String name = names.getString(k);
String value= obj.getString(name);
}
Il mio jsonbject sembra questo:
{"Table1": [], "CheckRecord": [{"mancata": 34, "frequentato": 12, "percentuale": 40, "rollno": "ABC2"}]}
Questo è ciò che la @GWA stava cercando di suggerire. Ti ho appena dato un campione di codice. Ottieni prima il tuo risultato e determina se è valido.
Spero che sia d'aiuto
Saluti
Altri suggerimenti
Allo stesso tempo, è necessario verificare il codice di risposta, utilizzando questo codice è possibile scoprire facilmente se la richiesta ha reso efficace o fallito a causa del server down o di qualsiasi altro motivo.
È possibile controllare il codice di stato di risposta utilizzando:
response.getStatusLine().getStatusCode();
Il problema è che stai creando un oggetto JSON usando una risposta che è vuota o non rappresenta una stringa JSON.
Quindi, dovresti creare un oggetto JSON in base alla tua risposta se:
- the status code is 200
- the response is not empty
- the response starts with '['
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