我正尝试在 Android Studio 中解析此 JSON 链接，但出现错误 E/ServiceHandler:无法从 url 获取任何数据。 https://api.jivedata.com/financials/detail/?ticker=aapl&elements=price_to_earnings
这是我的 MainActivity.java
package claudio.jivedatapeparsing;
import android.app.ListActivity;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.HashMap;
private static String url = "https://api.jivedata.com/financials/detail/?ticker=aapl&elements=price_to_earnings";
// JSON Node names
private static final String TAG_VALUE = "value";
private static final String TAG_TOTAL = "_total_";
private static final String TAG_RESULTS = "_results_";
private static final String TAG_PRICETOEARNINGS = "price_to_earnings";
JSONArray _total_ = null;
// Hashmap for ListView
// Hashmap is an implementation of map
ArrayList<HashMap<String, Integer>> contactList;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
contactList = new ArrayList<HashMap<String, Integer>>();
ListView lv = getListView();
new GetContacts().execute();
}
private class GetContacts extends AsyncTask<Void, Void, Void> {
//before it executes
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(MainActivity.this);
pDialog.setMessage("Please wait...");
pDialog.setCancelable(false);
pDialog.show();
}
@Override
protected Void doInBackground(Void... arg0) {
ServiceHandler sh = new ServiceHandler();
String jsonStr = sh.makeServiceCall(url, ServiceHandler.GET);
Log.d("Response: ", "> " + jsonStr);
if (jsonStr != null) {
try {
JSONObject jsonObject = new JSONObject(jsonStr);
JSONObject _results_ = jsonObject.getJSONObject(TAG_RESULTS);
JSONObject price_to_earnings = _results_.getJSONObject(TAG_PRICETOEARNINGS);
JSONArray _total_ = price_to_earnings.getJSONArray(TAG_TOTAL);
for (int i = 0; i < _total_.length(); i++) {
JSONObject c = _total_.getJSONObject(31);//get the latest P/E value
int value = c.getInt(TAG_VALUE);
HashMap<String, Integer> contact = new HashMap<String, Integer>();
contact.put(TAG_VALUE, value);
contactList.add(contact);
}
} catch (JSONException e) {
e.printStackTrace();
}
} else {
Log.e("ServiceHandler", "Couldn't get any data from the url");
}
return null;
}
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
if (pDialog.isShowing())
pDialog.dismiss();
ListAdapter adapter = new SimpleAdapter(
MainActivity.this, contactList,
R.layout.list_item, new String[] { TAG_VALUE }, new int[] { R.id.value });
setListAdapter(adapter);
}
}
}
这是 ServiceHandler.java:
package claudio.jivedatapeparsing;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.List;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.utils.URLEncodedUtils;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;
public class ServiceHandler {
static String response = null;
public final static int GET = 1;
public final static int POST = 2;
public ServiceHandler() {
}
/**
* Making service call
* @url - url to make request
* @method - http request method
* */
public String makeServiceCall(String url, int method) {
return this.makeServiceCall(url, method, null);
}
/**
* Making service call
* @url - url to make request
* @method - http request method
* @params - http request params
* */
public String makeServiceCall(String url, int method,
List<NameValuePair> params) {
try {
// http client
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpEntity httpEntity = null;
HttpResponse httpResponse = null;
// Checking http request method type
if (method == POST) {
HttpPost httpPost = new HttpPost(url);
// adding post params
if (params != null) {
httpPost.setEntity(new UrlEncodedFormEntity(params));
}
httpResponse = httpClient.execute(httpPost);
} else if (method == GET) {
if (params != null) {
String paramString = URLEncodedUtils
.format(params, "utf-8");
url += "?" + paramString;
}
HttpGet httpGet = new HttpGet(url);
httpResponse = httpClient.execute(httpGet);
}
httpEntity = httpResponse.getEntity();
response = EntityUtils.toString(httpEntity);
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return response;
}
}
最佳答案
编辑:我能够修改 ServiceHandler.java 类以使用 HTTPUrlConnection 而不是旧的 API，并且它起作用了。
修改后的 ServiceHandler.java:
import org.apache.http.NameValuePair;
import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.List;
public class ServiceHandler {
static String response = null;
public final static int GET = 1;
public final static int POST = 2;
HttpURLConnection urlConnection;
public ServiceHandler() {
}
/**
* Making service call
* @url - url to make request
* @method - http request method
* */
public String makeServiceCall(String url, int method) {
return this.makeServiceCall(url, method, null);
}
/**
* Making service call
* @url - url to make request
* @method - http request method
* @params - http request params
* */
public String makeServiceCall(String url, int method,
List<NameValuePair> params) {
StringBuilder result = new StringBuilder();
try {
URL urlObj = new URL(url);
urlConnection = (HttpURLConnection) urlObj.openConnection();
InputStream in = new BufferedInputStream(urlConnection.getInputStream());
BufferedReader reader = new BufferedReader(new InputStreamReader(in));
String line;
while ((line = reader.readLine()) != null) {
result.append(line);
}
}catch( Exception e) {
e.printStackTrace();
}
finally {
urlConnection.disconnect();
}
return result.toString();
}
}
MainActivity.java 中的响应日志:
04-10 17:00:00.351 22478-22517/com.networkjsontest.danu.networkjsontest D/Response:﹕ > {"_results_": {"_dates_": [{"end": "2009-09-26", "length": 12, "start": "2008-09-28"}, {"end": "2009-12-26", "length": 3, "start": "2009-09-27"}, {"end": "2010-03-27", "length": 3, "start": "2009-12-27"}, {"end": "2010-06-26", "length": 3, "start": "2010-03-28"}, {"end": "2010-06-26", "length": 9, "start": "2009-09-27"}, {"end": "2010-09-25", "length": 3, "start": "2010-06-27"}, {"end": "2010-09-25", "length": 12, "start": "2009-09-27"}, {"end": "2010-12-25", "length": 3, "start": "2010-09-26"}, {"end": "2011-03-26", "length": 3, "start": "2010-12-26"}, {"end": "2011-03-26", "length": 6, "start": "2010-09-26"}, {"end": "2011-06-25", "length": 3, "start": "2011-03-27"}, {"end": "2011-06-25", "length": 9, "start": "2010-09-26"}, {"end": "2011-09-24", "length": 3, "start": "2011-06-26"}, {"end": "2011-09-24", "length": 12, "start": "2010-09-26"}, {"end": "2011-12-31", "length": 3, "start": "2011-09-25"}, {"end": "2012-03-31", "length": 3, "start": "2012-01-01"}, {"end": "2012-03-31", "length": 6, "start": "2011-09-25"}, {"end": "2012-06-30", "length": 3, "start": "2012-04-01"}, {"end": "2012-06-30", "length": 9, "start": "2011-09-25"}, {"end": "2012-09-29", "length": 3, "start": "2012-07-01"}, {"end": "2012-09-29", "length": 12, "start": "2011-09-25"}, {"end": "2012-12-29", "length": 3, "start": "2012-09-30"}, {"end": "2013-03-30", "length": 3, "start": "2012-12-30"}, {"end": "2013-03-30", "length": 6, "start": "2012-09-30"}, {"end": "2013-06-29", "length": 3, "start": "2013-03-31"}, {"end": "2013-06-29", "length": 9, "start": "2012-09-30"}, {"end": "2013-09-28", "length": 3, "start": "2013-06-30"}, {"end": "2013-09-28", "length": 12, "start": "2012-09-30"}, {"end": "2013-12-28", "length": 3, "start": "2013-09-29"}, {"end": "2014-03-29", "length": 3, "start": "2013-12-29"}, {"end": "2014-03-29", "length": 6, "start": "2013-09-29"}, {"calculated": "LTM", "end": "2014-03-29", "length": 12, "start": "2013-03-31"}], "_labels_": {"price_to_earnings": "Price/Earnings"}, "price_to_earnings": {"_total_": [{"formatted": "86.5x", "value": 86.46023072252581}, {"formatted": "210.8x", "value": 210.7756068679692}, {"formatted": "231.6x", "value": 231.62003903708523}, {"formatted": "218.9x", "value": 218.87488472179527}, {"formatted": "73.4x", "value": 73.36424523441525}, {"formatted": "165.3x", "value": 165.27390900649954}, {"formatted": "50.8x", "value": 50.80996217797759}, {"formatted": "118.6x", "value": 118.58760826115923}, {"formatted": "118.9x", "value": 118.9243360614665}, {"formatted": "59.4x", "value": 59.37786673338337}, {"formatted": "97.4x", "value": 97.42747673782156}, {"formatted": "36.9x", "value": 36.893103269599465}, {"formatted": "107.5x", "value": 107.50415219688962}, {"formatted": "27.5x", "value": 27.467016433917134}, {"formatted": "54.5x", "value": 54.5009185548071}, {"formatted": "61.3x", "value": 61.26312166580623}, {"formatted": "28.8x", "value": 28.842258770153123}, {"formatted": "80.7x", "value": 80.68902991840436}, {"formatted": "21.2x", "value": 21.247388839152492}, {"formatted": "86.6x", "value": 86.58640398881187}, {"formatted": "17.1x", "value": 17.06083914408262}, {"formatted": "54.4x", "value": 54.442575317326806}, {"formatted": "74.6x", "value": 74.57840159212319}, {"formatted": "31.5x", "value": 31.46961325966851}, {"formatted": "103.2x", "value": 103.18840579710145}, {"formatted": "24.1x", "value": 24.115156646909398}, {"formatted": "94.8x", "value": 94.78168264110757}, {"formatted": "19.2x", "value": 19.224019224019223}, {"formatted": "54.5x", "value": 54.467564259485926}, {"formatted": "69.6x", "value": 69.64687469431674}, {"formatted": "30.6x", "value": 30.56449881948916}, {"formatted": "18.9x", "value": 18.882435622033043}]}}}
请注意，您的 JSON 解析代码没有正确解析它，因此您还有一些工作要做。
关于java - 在 Android Studio 中解析 JSON 对象，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/29570571/