Fit fields of a webservice

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My question is this: I need to access a server that provides me with the temperature of a place by indicating what that place is, from a Java application. For now that I get an http request request the problem is that they give me too much redundant information and I would like to know if there is any way to filter those fields received from the web service to stay alone with the ones I am interested in, which are tempMax and temMin. I leave here my code and the response I receive:

/// JAVA CODE 

public class WeatherService extends HttpServlet {

    public static void main(String[] args) {
        // System.out.println("\nOutput: \n" + callURL(
        // "https://www.yahoo.com/news/weather/spain/madrid/madrid-766273"));

        System.out
                .println("\nOutput: \n"
                        + callURL("http://api.openweathermap.org/data/2.5/forecast/daily?q=Madrid&mode=xml&units=metric&cnt=7&appid=f55938791241415bbd0917892e075f81"));


    }

    public static String callURL(String myURL) {
        System.out.println("Requeted 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();

    }
}

/// ANSWER I RECEIVED

Request URL: link

Output: 

<weatherdata><location><name>Madrid</name><type></type><country>ES</country><timezone></timezone><location altitude="0" latitude="40.4165" longitude="-3.70256" geobase="geonames" geobaseid="3117735"></location></location><credit></credit><meta><lastupdate></lastupdate><calctime>0.0094</calctime><nextupdate></nextupdate></meta><sun rise="2016-05-26T04:49:22" set="2016-05-26T19:35:01"></sun><forecast><time day="2016-05-26"><symbol number="804" name="overcast clouds" var="04d"></symbol><precipitation></precipitation><windDirection deg="230" code="SW" name="Southwest"></windDirection><windSpeed mps="2.41" name="Light breeze"></windSpeed><temperature day="23.15" min="12.75" max="24.29" night="12.75" eve="23.4" morn="23.15"></temperature><pressure unit="hPa" value="952.66"></pressure><humidity value="50" unit="%"></humidity><clouds value="overcast clouds" all="88" unit="%"></clouds></time><time day="2016-05-27"><symbol number="800" name="clear sky" var="01d"></symbol><precipitation></precipitation><windDirection deg="240" code="WSW" name="West-southwest"></windDirection><windSpeed mps="3.82" name="Gentle Breeze"></windSpeed><temperature day="24.11" min="11.12" max="25.63" night="12.01" eve="24.25" morn="11.12"></temperature><pressure unit="hPa" value="955.35"></pressure><humidity value="49" unit="%"></humidity><clouds value="clear sky" all="0" unit="%"></clouds></time><time day="2016-05-28"><symbol number="801" name="few clouds" var="02d"></symbol><precipitation></precipitation><windDirection deg="251" code="WSW" name="West-southwest"></windDirection><windSpeed mps="6.61" name="Moderate breeze"></windSpeed><temperature day="20.66" min="10.44" max="20.66" night="11.98" eve="17.8" morn="10.44"></temperature><pressure unit="hPa" value="955.48"></pressure><humidity value="52" unit="%"></humidity><clouds value="few clouds" all="12" unit="%"></clouds></time><time day="2016-05-29"><symbol number="500" name="light rain" var="10d"></symbol><precipitation value="0.61" type="rain"></precipitation><windDirection deg="259" code="W" name="West"></windDirection><windSpeed mps="4.16" name="Gentle Breeze"></windSpeed><temperature day="18.78" min="11.19" max="20.01" night="13.02" eve="18.24" morn="11.19"></temperature><pressure unit="hPa" value="958.87"></pressure><humidity value="60" unit="%"></humidity><clouds value="few clouds" all="20" unit="%"></clouds></time><time day="2016-05-30"><symbol number="800" name="clear sky" var="01d"></symbol><precipitation></precipitation><windDirection deg="318" code="NW" name="Northwest"></windDirection><windSpeed mps="2.11" name="Light breeze"></windSpeed><temperature day="20.02" min="9.76" max="21.74" night="12.5" eve="21.12" morn="9.76"></temperature><pressure unit="hPa" value="960.15"></pressure><humidity value="55" unit="%"></humidity><clouds value="clear sky" all="0" unit="%"></clouds></time><time day="2016-05-31"><symbol number="500" name="light rain" var="10d"></symbol><precipitation></precipitation><windDirection deg="75" code="ENE" name="East-northeast"></windDirection><windSpeed mps="1.55" name=""></windSpeed><temperature day="25.2" min="11.03" max="25.87" night="14.12" eve="25.87" morn="11.03"></temperature><pressure unit="hPa" value="948.44"></pressure><humidity value="0" unit="%"></humidity><clouds value="clear sky" all="6" unit="%"></clouds></time><time day="2016-06-01"><symbol number="800" name="clear sky" var="01d"></symbol><precipitation></precipitation><windDirection deg="63" code="ENE" name="East-northeast"></windDirection><windSpeed mps="1.46" name="Calm"></windSpeed><temperature day="26.77" min="11.33" max="27.27" night="14.92" eve="27.27" morn="11.33"></temperature><pressure unit="hPa" value="948.35"></pressure><humidity value="0" unit="%"></humidity><clouds value="scattered clouds" all="27" unit="%"></clouds></time></forecast></weatherdata>

Thank you very much

    
asked by Ricardo Regueiro 26.05.2016 в 17:07
source

2 answers

1

The URL contains information within an XML, what you can do is use 

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
import org.w3c.dom.Node;
import org.w3c.dom.Element;

That will allow you to parse the received String and search by Tag, that way you will only get the data you need. And already in the code: 

DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder(); 
Document doc = db.parse(new File(filename)); //filename sería tu String
NodeList nList = doc.getElementsByTagName("time"); 
//tendrás que filtrar esta lista para que solo te entregue los datos del día deseado.
for (int i = 0; int < nList.getLength(); i++) {
Node nNode = nList.item(temp);
Element eElement = (Element) nNode;
if (eElement.getAttribute("day")=="2016-05-27"){
     System.out.println("Máxima : " 
              + eElement.getElementsByTagName("temperature").item(0).getAttribute("max");
     System.out.println("Mínima : " 
              + eElement.getElementsByTagName("temperature").item(0).getAttribute("min");
     }
}

More information: link

    
answered by 26.05.2016 в 18:12
0

First of all, modifying the url of the webservice cnt=1 will bring only the information of today. (You should not add your KEY API, which should be private, now anyone can use it) 

http://api.openweathermap.org/data/2.5/forecast/daily?q=Madrid&mode=xml&units=metric&cnt=1&appid=API_KEY

Now to obtain the maximum and minimum values you must parse the xml. You can use Java XML DOM . 

        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        DocumentBuilder builder = factory.newDocumentBuilder();
        Document document = builder.parse(new File( file ));
        Element root = document.getDocumentElement();
        NodeList nList = document.getElementsByTagName("temperature");
        for (int temp = 0; temp < nList.getLength(); temp++)
        {
         Node node = nList.item(temp);
         System.out.println("");    //Just a separator
         if (node.getNodeType() == Node.ELEMENT_NODE)
         {
            //Print each employee's detail
            Element eElement = (Element) node;

            System.out.println("min:"+eElement.getElementsByTagName("min").item(0).getTextContent());
            System.out.println("min:"+eElement.getElementsByTagName("max").item(0).getTextContent());
         }
        }

It may be that you have to make some adjustment to the previous code since I do not have an IDE at hand to validate.

A good XML DOM tutorial can be found here: link

    
answered by 26.05.2016 в 18:01
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