Question

当URL =“http://rest.riob.us/v3/search/474”时，

以下我的代码工作正常。

但是为URL =“http://dadosabertos.rio.rj.gov.br/apiTransporte/apresentacao/rest/index.cfm/onibus/474”返回null。

这两个网址在webbrowser上运行良好。

这是我的代码：

public class HttpGetAsyncTask  extends AsyncTask<String, Void, String> {
@Override
protected String doInBackground(String... urls) {

    return GET(urls[0]);
}
// onPostExecute displays the results of the AsyncTask.
@Override
protected void onPostExecute(String result) {

    Log.w("TAG", "result: " + result);
}

public static String GET(String url){
    InputStream inputStream = null;
    String result = "";
    try {

        // create HttpClient
        HttpClient httpclient = new DefaultHttpClient();

        // make GET request to the given URL
        HttpResponse httpResponse = httpclient.execute(new HttpGet(url));

        // receive response as inputStream
        inputStream = httpResponse.getEntity().getContent();

        Log.v("TAG", "inputStream: " + inputStream);
        Log.e("TAG", "httpResponse.getEntity().getContentLength(): " + httpResponse.getEntity().getContentLength());

        // convert inputstream to string
        if(inputStream != null)
            result = convertInputStreamToString(inputStream);
        else
            result = "Did not work!";

    } catch (Exception e) {
        Log.d("TAG", e.getLocalizedMessage());
    }

    return result;
} 

private static String convertInputStreamToString(InputStream inputStream) throws IOException{
    BufferedReader bufferedReader = new BufferedReader( new InputStreamReader(inputStream));
    String line = "";
    String result = "";
    while((line = bufferedReader.readLine()) != null)
        result += line;

    inputStream.close();
    return result;

}

}

可能有什么不对？事先提前

Answer 1

如果您正在对API或JSON进行网络请求，请查看VOLLEY库。它使用起来非常简单，它可以为您处理排队，异步和缓存。例如：

RequestQueue queue = Volley.newRequestQueue(this);

JsonObjectRequest request = new JsonObjectRequest(Request.Method.GET, URL, new Response.Listener<JSONObject>() {
        @Override
        public void onResponse(JSONObject response) {
            //DO WITH RESPONSE
        }
    }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            //CRAP ERROR
            Log.e("Volley", error.toString());
        }
    });
queue.add(request);

严重如果您要请求JSON数据，请使用Volley，这样简单得多！这是JSON请求所需的所有代码，它还为Images或Strings提供了其他内置请求类型，甚至允许自定义类型。

HttpGet为特定网址返回null

1 个答案: