Using Java to retrieve data from the Google Weather API

Question

I recently talked with XML documents and java, but I was not able to use the Google Weather API.

Suppose I try to make a simple object to store the current tempo and predict the tempo only tomorrow, how would I do it?

http://www.google.com/ig/api?weather=02110 Is a working example for my hometown.

thanks

Using this code:

public static final String[] xmlLoader(){ String xmlData[] = new String[2]; try { URL googleWeatherXml = new URL("http://www.google.com/ig/api?weather=02110"); DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); DocumentBuilder db = dbf.newDocumentBuilder(); Document doc = db.parse(googleWeatherXml.openStream()); // normalize text representation doc.getDocumentElement ().normalize (); NodeList listOfWeek = doc.getElementsByTagName(""); Node firstWeekNode = listOfWeek.item(dateCounter-1); int totalWeeks = listOfWeek.getLength(); //Break xml file into parts, then break those parts down int an array by passing individual elements to srtings if(firstWeekNode.getNodeType() == Node.ELEMENT_NODE){ Element firstWeekElement = (Element)firstWeekNode; //------- NodeList dateList = firstWeekElement.getElementsByTagName("date"); Element dateElement = (Element)dateList.item(0); NodeList textDateList = dateElement.getChildNodes(); xmlData[0]= (((Node)textDateList.item(0)).getNodeValue().trim()).toString(); //------- NodeList riddleList = firstWeekElement.getElementsByTagName("riddle"); Element riddleElement = (Element)riddleList.item(0); NodeList textRiddleList = riddleElement.getChildNodes(); xmlData[1]= (((Node)textRiddleList.item(0)).getNodeValue().trim()).toString(); //---- NodeList lWSList = firstWeekElement.getElementsByTagName("lastWeekSolution"); Element ageElement = (Element)lWSList.item(0); NodeList textLWSList = ageElement.getChildNodes(); xmlData[2]= (((Node)textLWSList.item(0)).getNodeValue().trim()).toString(); //------ }//end of if clause } catch(MalformedURLException f){System.err.println(f.getMessage()); } catch(NullPointerException npe){ System.out.println("The Weather Data you searched for is incorrect or does not yet exist, try again. "); String s[] = {" ", " "}; main(s); } catch (SAXParseException err) { System.out.println ("** Parsing error" + ", line " + err.getLineNumber () + ", uri " + err.getSystemId ()); System.out.println(" " + err.getMessage ()); } catch (SAXException e) { Exception x = e.getException (); ((x == null) ? e : x).printStackTrace (); }catch (Throwable t) { t.printStackTrace (); } return xmlData; } 

Getting tons of null pointers, no matter what I do.

Answer 1

When you call .getElementsByTagName (), you need to arm the return value:

 NodeList dateList = firstWeekElement.getElementsByTagName("date"); if (datelist != null) { Element dateElement = (Element)dateList.item(0); 

et cetera.

Update

Now, when I look at XML, I see that there are no <date> elements; so why is DateList null. You want to search for elements such as <forecast_information> and <city>.

 NodeList forecasts = firstWeekElement.getElementsByTagName("forecast_information"); if (forecasts != null) { Element forecastElement = (Element)forecasts.item(0);