Here is code of my getStream method:
public static Twitch_Stream getStream(String channelname) {
try {
String json = API.readJsonFromUrl("https://api.twitch.tv/kraken/streams?channel=" + channelname);
Twitch_Stream stream = new Twitch_Stream();
if (json.equalsIgnoreCase("[]")) {
stream.setOnline(false);
return stream;
}
JsonArray jb = gson.fromJson(json, JsonArray.class);
if (jb.size() != 0) {
JsonObject jo = (JsonObject) jb.get(0);
stream.setOnline(true);
stream.load(jo);
}
return stream;
} catch (Exception error) {
error.printStackTrace();
}
return null;
}
and here is code of Twitch_Stream class http://pastebin.com/3RX1L1cv
When I make something like this
Twitch_Stream streamer = Twitch_API.getStream("Jankos");
Bukkit.broadcastMessage("getName " + streamer.getName());
Bukkit.broadcastMessage(streamer.isOnline() + "");
streamer.getName() return null and streamer.isOnline() returns false, even when stream is on.
Where did I make a mistake?
I don't know what problem is in your code but simple workaround would be reading content from "https://api.twitch.tv/kraken/streams/" + channel which is JSON in format:
{
"_links" : {
//links to stream and channel
},
"stream" : {
//details about current stream
}
}
Now if value of stream key is null stream is off-line. If it is not null, it is on-line.
So your code can look like
public static void main(String[] argv) throws IOException {
System.out.println(checkIfOnline("Jankos"));
System.out.println(checkIfOnline("nightblue3"));
}
public static boolean checkIfOnline(String channel) throws IOException {
String channerUrl = "https://api.twitch.tv/kraken/streams/" + channel;
String jsonText = readFromUrl(channerUrl);// reads text from URL
JSONObject json = new JSONObject(jsonText);
return !json.isNull("stream");
}
private static String readFromUrl(String url) throws IOException {
URL page = new URL(url);
try (Stream<String> stream = new BufferedReader(new InputStreamReader(
page.openStream(), StandardCharsets.UTF_8)).lines()) {
return stream.collect(Collectors.joining(System.lineSeparator()));
}
}
I used JSONObject from org.json library. I am also using Java 8 and its streams.
If you want to use gson you can use instead something like
public static boolean checkIfOnline(String channel) throws IOException {
String channerUrl = "https://api.twitch.tv/kraken/streams/" + channel;
String jsonText = readFromUrl(channerUrl);// reads text from URL
JsonParser parser = new JsonParser();
JsonObject json = parser.parse(jsonText).getAsJsonObject();
return !json.get("stream").isJsonNull();
}
If you don't have Java 8 you can rewrite code reading text from URL to something like
private static String readFromUrl(String url) throws IOException {
URL page = new URL(url);
StringBuilder sb = new StringBuilder();
Scanner scanner = null;
try{
scanner = new Scanner(page.openStream(), StandardCharsets.UTF_8.name());
while (scanner.hasNextLine()){
sb.append(scanner.nextLine());
}
}finally{
if (scanner!=null)
scanner.close();
}
return sb.toString();
}
or from what I see you can use your API.readJsonFromUrl instead of readFromUrl.
Related
so i have this class
public static String ip (String url){
try {
String webPagea = url;
URL urla = new URL(webPagea);
URLConnection urlConnectiona = urla.openConnection();
InputStream isa = urlConnectiona.getInputStream();
InputStreamReader isra = new InputStreamReader(isa);
int numCharsReada;
char[] charArraya = new char[1024];
StringBuffer sba = new StringBuffer();
while ((numCharsReada = isra.read(charArraya)) > 0) {
sba.append(charArraya, 0, numCharsReada);
}
String resulta = sba.toString();
return resulta;
} catch (Exception e)
{
}
**(compile error)
}
and i want the above to return the resulta string when called from another class like below:
private class t1 implements Runnable{
public void run() {
String getip= ip("http://google.com");
}
but i get compile error that i didn't add a return statement above where the 2 stars are.
Also in general when i define a string within a try catch like above i cant access it outside the try/catch what am i doing wrong ?
example:
public void haha(String data)
{
try {
string test="test6";
} catch (Exception e)
}
string vv=test; <--test cannot be found
}
I want to emphasize i want to get the output of the page not the source code
if the website outputs text i want just the text not the html code
cheers
The scope of the string resulta is within the bounds of the try block. Modify you rcode to have the string resulta declared outside the try block, like this:
public static String ip (String url){
String resulta = "";
try {
String webPagea = url;
URL urla = new URL(webPagea);
URLConnection urlConnectiona = urla.openConnection();
InputStream isa = urlConnectiona.getInputStream();
InputStreamReader isra = new InputStreamReader(isa);
int numCharsReada;
char[] charArraya = new char[1024];
StringBuffer sba = new StringBuffer();
while ((numCharsReada = isra.read(charArraya)) > 0) {
sba.append(charArraya, 0, numCharsReada);
}
resulta = sba.toString();
} catch (Exception e) {
}
return resulta;
}
Here is the entire class:
public class Item {
static class Page {
Map <String,String> other_data;
Map <String,Map<String,List<Map<String,String>>>> specification;
}
public static String showName() throws Exception {
String json = Json.fetch(jsonurl);
Gson gson = new Gson();
Page result = gson.fromJson(json, Page.class);
return result.specification.get("result").get("feature").get(0).get("value");
// not working.
//return result.other_data.get("id"); <-- this one working
}
}
Here's how I fetch the json:
public class Json {
public static String fetch(String urlString) throws Exception {
BufferedReader reader = null;
try {
reader = new BufferedReader(new InputStreamReader(Connection.auth(urlString)));
StringBuffer buffer = new StringBuffer();
int read;
char[] chars = new char[1024];
while ((read = reader.read(chars)) != -1)
buffer.append(chars, 0, read);
//return buffer.toString();
return buffer.toString();
} finally {
if (reader != null)
reader.close();
}
}
}
I have been struggling to get a specific value from a mixed-type JSON feed using gson.
{
"other_data":{"id":"150","name":"AA"},
"specification":{"result":{"feature":[{"name":"attribute A","value":"50"}]}}
}
The feed should be valid since I can get 150 from other_data
`return result.other_data.get("id");`
However I can't get the value 50 from the first object of the array feature:
return result.specification.get("result").get("feature").get(0).get("value");
I'm receiving this error:
Expected BEGIN_OBJECT but was STRING at line 1 column 37948 path $.specification.
I think the declaration Map <String,Map<String,List<Map<String,String>>>> specification; is incorrect. I did a little debugging by changing it to Map <String,Object> specification. I managed to get the stringified object
{"feature":[{"name":"attribute A","value":"50"}]}
public class Item {
static class Page {
String page_type;
String name;
Map <String,String> submit_user_data;
Map <String,Object> specification;
}
public static String showName() throws Exception {
String json = Json.fetch(jsonurl);
Gson gson = new Gson();
Page td = gson.fromJson(json, Page.class);
return td.specification.get("result").toString(); // this one works!
}
}
Would anyone tell me what's wrong with the class getting the error?
Apparently escaping the json string solves the issue:
public static void main(String args[]) {
String json = "{\"other_data\":{\"id\":\"150\",\"name\":\"AA\"},\"specification\":{\"result\":{\"feature\":[{\"name\":\"attribute A\",\"value\":\"50\"}]}}}";
Gson gson = new Gson();
Page result = gson.fromJson(json, Page.class);
System.out.println(result.specification.get("result").get("feature").get(0).get("value"));
}
I am trying to write an automated Java test where the code will go to a specified URL, read the JSON data and print it up.
Here is the JSON I am trying to access;
{
"status": "success",
"records": [
{
"timestamp": 1381222871868,
"deviceId": "288",
"temperature": 17
},
{
"timestamp": 1381222901868,
"deviceId": "288",
"temperature": 17
},
{
"timestamp": 1381222931868,
"deviceId": "288",
"temperature": 17
},
]}
As you can see I only have 3 elements, Timestamp, DeviceId and Temperature.
What I am ultimately aiming for it to be able to get 2 Timestamp values and take one value away from the other, if that is possible.
Anyway I have been trying to do this all day and am having no luck whatsoever. I was recommended to use Gson and I have included the jar files into my classpath.
If anyone knows anything or can help me in any way it would be much appreciated as I have exhausted Google and myself trying to work this out.
Here is the code I have to display the full list, but I do not fully understand it and so far can't manipulate it to my advantage;
public static void main(String[] args) throws Exception
{
String jsonString = callURL("http://localhost:8000/eem/api/v1/metrics/temperature/288");
System.out.println("\n\njsonString: " + jsonString);
// Replace this try catch block for all below subsequent examples
/*try
{
JSONArray jsonArray = new JSONArray(jsonString);
System.out.println("\n\njsonArray: " + jsonArray);
}
catch (JSONException e)
{
e.printStackTrace();
}*/
try
{
JSONArray jsonArray = new JSONArray(jsonString);
int count = jsonArray.length(); // get totalCount of all jsonObjects
for(int i=0 ; i< count; i++)
{ // iterate through jsonArray
JSONObject jsonObject = jsonArray.getJSONObject(i); // get jsonObject # i position
System.out.println("jsonObject " + i + ": " + jsonObject);
}
}
catch (JSONException e)
{
e.printStackTrace();
}
}
public static String callURL(String myURL)
{
//System.out.println("Requested URL:" + myURL);
StringBuilder sb = new StringBuilder();
URLConnection urlConn = null;
InputStreamReader in = null;
try
{
URL url = new URL(myURL);
urlConn = url.openConnection();
if (urlConn != null)
{
urlConn.setReadTimeout(60 * 1000);
}
if (urlConn != null && urlConn.getInputStream() != null)
{
in = new InputStreamReader(urlConn.getInputStream(),
Charset.defaultCharset());
BufferedReader bufferedReader = new BufferedReader(in);
if (bufferedReader != null)
{
int cp;
while ((cp = bufferedReader.read()) != -1)
{
sb.append((char) cp);
}
bufferedReader.close();
}
}
in.close();
}
catch (Exception e)
{
throw new RuntimeException("Exception while calling URL:"+ myURL, e);
}
return sb.toString();
}
Cheers
I had read the values from file but you can read from URL, the extracting process code is present inside extractJson() method.
public static void main(String [] args)
{
try
{
FileInputStream fis=new FileInputStream("testjson.json");
int b=0;
String val="";
while((b=fis.read())!=-1)
{
val=val+(char)b;
}
extractJson(val);
}
catch(Exception e)
{
e.printStackTrace();
}
}
public static void extractJson(String json)
{
try
{
JSONObject jobject=new JSONObject(json);
System.out.println("Json object Length: "+jobject.length());
System.out.println("Status: "+jobject.getString("status"));
JSONArray jarray=new JSONArray(jobject.getString("records"));
System.out.println("Json array Length: "+jarray.length());
for(int j=0;j<jarray.length();j++)
{
JSONObject tempObject=jarray.getJSONObject(j);
System.out.println("Timestamp: "+tempObject.getString("timestamp"));
System.out.println("Device Id: "+tempObject.getString("deviceId"));
System.out.println("Temperature: "+tempObject.getString("temperature"));
}
}
catch(Exception e)
{
e.printStackTrace();
}
}
You could use ArrayList to store the values which will be available inside for loop. From your question you need to pass jsonString this variable to the extractJson() method. Use org.json jar file to process json. If you could alter this for gson then it'll be good for your requirement.
here's how to do it via Google-Gson
class MyRecord
{
private long timestamp;
private String deviceId;
private Integer temperature;
//Getters & setters
}
public static void main(String... args){
String myJsonString=callUrl("http://mydomain.com/x.json");
JsonParser jp = new JsonParser();
JsonElement ele = jp.parse(myJsonString);
Gson gg = new Gson();
Type type = new TypeToken<List<MyRecord>>() {
}.getType();
List<MyRecord> lst= gg.fromJson(ele.getAsJsonObject().get("records"), type);
//Now the json is parsed in a List of MyRecord, do whatever you want to with it
}
An "high-level" Gson parsing answer:
package stackoverflow.questions.q19252374;
import java.util.List;
import com.google.gson.Gson;
public class Q19252374 {
class Record {
Long timestamp;
String deviceId;
Long temperature;
}
class Container {
List<Record> records;
}
public static void main(String[] args) {
String json = "{ \"status\": \"success\", \"records\": [{\"timestamp\": 1381222871868,\"deviceId\": \"288\",\"temperature\": 17 },{\"timestamp\": 1381222901868,\"deviceId\": \"288\",\"temperature\": 17 },{\"timestamp\": 1381222931868,\"deviceId\": \"288\",\"temperature\": 17 } ]} ";
Gson g = new Gson();
Container c = g.fromJson(json, Container.class);
for (Record r : c.records)
System.out.println(r.timestamp);
}
}
Of course this is the result:
1381222871868
1381222901868
1381222931868
Does anyone know where to find a little how to on using dbpedia spotlight in java or scala? Or could anyone explain how it's done? I can't find any information on this...
The DBpedia Spotlight wiki pages would be a good place to start.
And I believe the installation page has listed the most popular ways (using a jar, or set up a web service) to use the application.
It includes instructions on using the Java/Scala API with your own installation, or calling the Web Service.
There are some additional data needed to be downloaded to run your own server for full service, good time to make a coffee for yourself.
you need download dbpedia spotlight (jar file) after that u can use next two classes ( author pablomendes ) i only make some change .
public class db extends AnnotationClient {
//private final static String API_URL = "http://jodaiber.dyndns.org:2222/";
private static String API_URL = "http://spotlight.dbpedia.org:80/";
private static double CONFIDENCE = 0.0;
private static int SUPPORT = 0;
private static String powered_by ="non";
private static String spotter ="CoOccurrenceBasedSelector";//"LingPipeSpotter"=Annotate all spots
//AtLeastOneNounSelector"=No verbs and adjs.
//"CoOccurrenceBasedSelector" =No 'common words'
//"NESpotter"=Only Per.,Org.,Loc.
private static String disambiguator ="Default";//Default ;Occurrences=Occurrence-centric;Document=Document-centric
private static String showScores ="yes";
#SuppressWarnings("static-access")
public void configiration(double CONFIDENCE,int SUPPORT,
String powered_by,String spotter,String disambiguator,String showScores){
this.CONFIDENCE=CONFIDENCE;
this.SUPPORT=SUPPORT;
this.powered_by=powered_by;
this.spotter=spotter;
this.disambiguator=disambiguator;
this.showScores=showScores;
}
public List<DBpediaResource> extract(Text text) throws AnnotationException {
LOG.info("Querying API.");
String spotlightResponse;
try {
String Query=API_URL + "rest/annotate/?" +
"confidence=" + CONFIDENCE
+ "&support=" + SUPPORT
+ "&spotter=" + spotter
+ "&disambiguator=" + disambiguator
+ "&showScores=" + showScores
+ "&powered_by=" + powered_by
+ "&text=" + URLEncoder.encode(text.text(), "utf-8");
LOG.info(Query);
GetMethod getMethod = new GetMethod(Query);
getMethod.addRequestHeader(new Header("Accept", "application/json"));
spotlightResponse = request(getMethod);
} catch (UnsupportedEncodingException e) {
throw new AnnotationException("Could not encode text.", e);
}
assert spotlightResponse != null;
JSONObject resultJSON = null;
JSONArray entities = null;
try {
resultJSON = new JSONObject(spotlightResponse);
entities = resultJSON.getJSONArray("Resources");
} catch (JSONException e) {
//throw new AnnotationException("Received invalid response from DBpedia Spotlight API.");
}
LinkedList<DBpediaResource> resources = new LinkedList<DBpediaResource>();
if(entities!=null)
for(int i = 0; i < entities.length(); i++) {
try {
JSONObject entity = entities.getJSONObject(i);
resources.add(
new DBpediaResource(entity.getString("#URI"),
Integer.parseInt(entity.getString("#support"))));
} catch (JSONException e) {
LOG.error("JSON exception "+e);
}
}
return resources;
}
}
second class
/**
* #author pablomendes
*/
public abstract class AnnotationClient {
public Logger LOG = Logger.getLogger(this.getClass());
private List<String> RES = new ArrayList<String>();
// Create an instance of HttpClient.
private static HttpClient client = new HttpClient();
public List<String> getResu(){
return RES;
}
public String request(HttpMethod method) throws AnnotationException {
String response = null;
// Provide custom retry handler is necessary
method.getParams().setParameter(HttpMethodParams.RETRY_HANDLER,
new DefaultHttpMethodRetryHandler(3, false));
try {
// Execute the method.
int statusCode = client.executeMethod(method);
if (statusCode != HttpStatus.SC_OK) {
LOG.error("Method failed: " + method.getStatusLine());
}
// Read the response body.
byte[] responseBody = method.getResponseBody(); //TODO Going to buffer response body of large or unknown size. Using getResponseBodyAsStream instead is recommended.
// Deal with the response.
// Use caution: ensure correct character encoding and is not binary data
response = new String(responseBody);
} catch (HttpException e) {
LOG.error("Fatal protocol violation: " + e.getMessage());
throw new AnnotationException("Protocol error executing HTTP request.",e);
} catch (IOException e) {
LOG.error("Fatal transport error: " + e.getMessage());
LOG.error(method.getQueryString());
throw new AnnotationException("Transport error executing HTTP request.",e);
} finally {
// Release the connection.
method.releaseConnection();
}
return response;
}
protected static String readFileAsString(String filePath) throws java.io.IOException{
return readFileAsString(new File(filePath));
}
protected static String readFileAsString(File file) throws IOException {
byte[] buffer = new byte[(int) file.length()];
#SuppressWarnings("resource")
BufferedInputStream f = new BufferedInputStream(new FileInputStream(file));
f.read(buffer);
return new String(buffer);
}
static abstract class LineParser {
public abstract String parse(String s) throws ParseException;
static class ManualDatasetLineParser extends LineParser {
public String parse(String s) throws ParseException {
return s.trim();
}
}
static class OccTSVLineParser extends LineParser {
public String parse(String s) throws ParseException {
String result = s;
try {
result = s.trim().split("\t")[3];
} catch (ArrayIndexOutOfBoundsException e) {
throw new ParseException(e.getMessage(), 3);
}
return result;
}
}
}
public void saveExtractedEntitiesSet(String Question, LineParser parser, int restartFrom) throws Exception {
String text = Question;
int i=0;
//int correct =0 ; int error = 0;int sum = 0;
for (String snippet: text.split("\n")) {
String s = parser.parse(snippet);
if (s!= null && !s.equals("")) {
i++;
if (i<restartFrom) continue;
List<DBpediaResource> entities = new ArrayList<DBpediaResource>();
try {
entities = extract(new Text(snippet.replaceAll("\\s+"," ")));
System.out.println(entities.get(0).getFullUri());
} catch (AnnotationException e) {
// error++;
LOG.error(e);
e.printStackTrace();
}
for (DBpediaResource e: entities) {
RES.add(e.uri());
}
}
}
}
public abstract List<DBpediaResource> extract(Text text) throws AnnotationException;
public void evaluate(String Question) throws Exception {
evaluateManual(Question,0);
}
public void evaluateManual(String Question, int restartFrom) throws Exception {
saveExtractedEntitiesSet(Question,new LineParser.ManualDatasetLineParser(), restartFrom);
}
}
main()
public static void main(String[] args) throws Exception {
String Question ="Is the Amazon river longer than the Nile River?";
db c = new db ();
c.configiration(0.0, 0, "non", "CoOccurrenceBasedSelector", "Default", "yes");
System.out.println("resource : "+c.getResu());
}
I just add one little fix for your answer.
Your code is running, if you add the evaluate method call:
public static void main(String[] args) throws Exception {
String question = "Is the Amazon river longer than the Nile River?";
db c = new db ();
c.configiration(0.0, 0, "non", "CoOccurrenceBasedSelector", "Default", "yes");
c.evaluate(question);
System.out.println("resource : "+c.getResu());
}
Lamine
In the request method of the second class (AnnotationClient) in Adel's answer, the author Pablo Mendes hasn't finished
TODO Going to buffer response body of large or unknown size. Using getResponseBodyAsStream instead is recommended.
which is an annoying warning that needs to be removed by replacing
byte[] responseBody = method.getResponseBody(); //TODO Going to buffer response body of large or unknown size. Using getResponseBodyAsStream instead is recommended.
// Deal with the response.
// Use caution: ensure correct character encoding and is not binary data
response = new String(responseBody);
with
Reader in = new InputStreamReader(method.getResponseBodyAsStream(), "UTF-8");
StringWriter writer = new StringWriter();
org.apache.commons.io.IOUtils.copy(in, writer);
response = writer.toString();
I'm trying to get the hits of a google search from a string of the query.
public class Utils {
public static int googleHits(String query) throws IOException {
String googleAjax = "http://ajax.googleapis.com/ajax/services/search/web?v=1.0&q=";
String json = stringOfUrl(googleAjax + query);
JsonObject hits = new Gson().fromJson(json, JsonObject.class);
return hits.get("estimatedResultCount").getAsInt();
}
public static String stringOfUrl(String addr) throws IOException {
ByteArrayOutputStream output = new ByteArrayOutputStream();
URL url = new URL(addr);
IOUtils.copy(url.openStream(), output);
return output.toString();
}
public static void main(String[] args) throws URISyntaxException, IOException {
System.out.println(googleHits("odp"));
}
}
The following exception is thrown:
Exception in thread "main" java.lang.NullPointerException
at odp.compling.Utils.googleHits(Utils.java:48)
at odp.compling.Utils.main(Utils.java:59)
What am I doing incorrectly? Should I be defining an entire object for the Json return? That seems excessive, given that all I want to do is get one value.
For reference: the returned JSON structure.
Looking the returned JSON, it seems that you're asking for the estimatedResultsCount member of the wrong object. You're asking for hits.estimatedResultsCount, but you need hits.responseData.cursor.estimatedResultsCount. I'm not super familiar with Gson, but I think you should do something like:
return hits.get("responseData").get("cursor").get("estimatedResultsCount");
I tried this and it worked, using JSON and not GSON.
public static int googleHits(String query) throws IOException,
JSONException {
String googleAjax = "http://ajax.googleapis.com/ajax/services/search/web?v=1.0&q=";
URL searchURL = new URL(googleAjax + query);
URLConnection yc = searchURL.openConnection();
BufferedReader in = new BufferedReader(new InputStreamReader(
yc.getInputStream()));
String jin = in.readLine();
System.out.println(jin);
JSONObject jso = new JSONObject(jin);
JSONObject responseData = (JSONObject) jso.get("responseData");
JSONObject cursor = (JSONObject) responseData.get("cursor");
int count = cursor.getInt("estimatedResultCount");
return count;
}