I making a java application that give the user notification with the weather conditions.
i used the yahoo weather API provided by yahoo like that link :
http://weather.yahooapis.com/forecastrss?w=2502265
and all i have to do is to change the eight numbered code that is in the URL in order to change the city.
that's working perfect, but there are two problems facing me now:
the first one, i want to implement a lot of weather forecast sources in my application not just the yahoo weather and i can't find a similar service in any other weather forecast websites.
the second one, i want to obtain the codes of all the cities in yahoo weather as for sure i won't ask the user to enter his city code, but to enter his city name and i'll match it with the code.
and here is the code that works with me in java:
the code to return the XML file:
package search;
import java.io.IOException;
import java.io.InputStream;
import java.io.StringWriter;
import java.net.URL;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Document;
public class Process {
public static void main(String[] args) throws IOException {
Display disp = new Display();
Document doc = generateXML("1940345");
disp.getConditions(doc);
}
public static Document generateXML(String code) throws IOException {
String url = null;
String XmlData = null;
// creating the URL
url = "http://weather.yahooapis.com/forecastrss?w=" + code;
URL xmlUrl = new URL(url);
InputStream in = xmlUrl.openStream();
// parsing the XmlUrl
Document doc = parse(in);
return doc;
}
public static Document parse(InputStream is) {
Document doc = null;
DocumentBuilderFactory domFactory;
DocumentBuilder builder;
try {
domFactory = DocumentBuilderFactory.newInstance();
domFactory.setValidating(false);
domFactory.setNamespaceAware(false);
builder = domFactory.newDocumentBuilder();
doc = builder.parse(is);
} catch (Exception ex) {
System.err.println("unable to load XML: " + ex);
}
return doc;
}
}
the code to display the temperature and humidity in that city :
package search;
import java.io.File;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
public class Display {
static void getConditions(Document doc) {
String city = null;
String unit = null;
try {
doc.getDocumentElement().normalize();
NodeList nList = doc.getElementsByTagName("rss");
for (int temp = 0; temp < nList.getLength(); temp++) {
Node nNode = nList.item(temp);
if (nNode.getNodeType() == Node.ELEMENT_NODE) {
Element eElement = (Element) nNode;
NodeList nl = eElement
.getElementsByTagName("yweather:location");
for (int tempr = 0; tempr < nl.getLength(); tempr++) {
Node n = nl.item(tempr);
if (nNode.getNodeType() == Node.ELEMENT_NODE) {
Element e = (Element) n;
city = e.getAttribute("city");
System.out.println("The City Is : " + city);
}
}
NodeList nl2 = eElement
.getElementsByTagName("yweather:units");
for (int tempr = 0; tempr < nl2.getLength(); tempr++) {
Node n2 = nl2.item(tempr);
if (nNode.getNodeType() == Node.ELEMENT_NODE) {
Element e2 = (Element) n2;
unit = e2.getAttribute("temperature");
}
}
NodeList nl3 = eElement
.getElementsByTagName("yweather:condition");
for (int tempr = 0; tempr < nl3.getLength(); tempr++) {
Node n3 = nl3.item(tempr);
if (nNode.getNodeType() == Node.ELEMENT_NODE) {
Element e3 = (Element) n3;
System.out.println("The Temperature In " + city
+ " Is : " + e3.getAttribute("temp") + " "
+ unit);
}
}
NodeList nl4 = eElement
.getElementsByTagName("yweather:atmosphere");
for (int tempr = 0; tempr < nl4.getLength(); tempr++) {
Node n4 = nl4.item(tempr);
if (nNode.getNodeType() == Node.ELEMENT_NODE) {
Element e4 = (Element) n4;
System.out.println("The Humidity In " + city
+ " Is : " + e4.getAttribute("humidity"));
}
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
You can use Metwit weather api simply passing latitude and longitude.
If you can implement them client-side: 200 request/day (ip based throttling) no authentication required. Worldwide coverage, JSON and REST compliant. You can register for extra API calls for free and if you still need it to call them server side the basic plan is pretty cheap.
Full disclosure: I own this API.
Take a look on this discussion. It seems relevant:
https://stackoverflow.com/questions/4876800/is-there-an-international-weather-forecast-api-that-is-not-limited-for-non-comme
Additionally type "weather forecast api" in google. There are tons of references to APIs that support several weather services.
Here's a list of Weather APIs that are available via the Temboo Java SDK:
https://temboo.com/library/keyword/weather/
You can use YQL (yahoo query language) to find the WOEID by city name like
var lclqry = escape('select * from geo.places where text="OKLAHOMA CITY"')
var lclurl = "http://query.yahooapis.com/v1/public/yql?q=" + lclqry + "&format=json&callback=?";
I know this is an old question, but i found it and as Sai suggested i have written code in java that send YQL query and retrieve WOEID number. Than it uses it to get weather from yahoo-weather-java-api. It needs gson dependecy which you can get by adding dependency to maven. I hope this will help someone.
EDIT
If there is more than one WOEID number for given town name, than getWeather returns weather for town with first WOEID returned.
CODE
Weather.java:
import com.github.fedy2.weather.YahooWeatherService;
import com.github.fedy2.weather.data.Channel;
import com.github.fedy2.weather.data.unit.DegreeUnit;
import com.google.gson.*;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLEncoder;
import javax.xml.bind.JAXBException;
/**
*
* #author robert
*/
public class Weather
{
public Channel getWeather(String townName) throws CantFindWeatherException
{
try
{
String baseUrl = "http://query.yahooapis.com/v1/public/yql?q=";
String query =
"select woeid from geo.places where text=\"" +
townName + "\"";
String fullUrlStr = baseUrl + URLEncoder.encode(query, "UTF-8") +
"&format=json";
URL fullUrl = new URL(fullUrlStr);
ResultObject resultObject = null;
ResultArray resultArray = null;
try (InputStream is = fullUrl.openStream();
InputStreamReader isr = new InputStreamReader(is);
BufferedReader br = new BufferedReader(isr))
{
String result = "";
String read;
while ((read = br.readLine()) != null)
{
result += read;
}
Gson gson = new Gson();
try
{
resultObject = gson.fromJson(result, ResultObject.class);
}
catch (com.google.gson.JsonSyntaxException ex)
{
resultArray = gson.fromJson(result, ResultArray.class);
}
}
Integer woeid = null;
if (resultObject != null)
{
if (resultObject.query.results != null)
{
woeid = resultObject.query.results.place.woeid;
}
}
else if (resultArray != null)
{
woeid = resultArray.query.results.place[0].woeid;
}
if (woeid != null)
{
YahooWeatherService service = new YahooWeatherService();
Channel channel = service.getForecast(woeid.toString(),
DegreeUnit.CELSIUS);
return channel;
}
else
{
throw new CantFindWeatherException();
}
}
catch (IOException | JsonSyntaxException | JAXBException ex)
{
throw new CantFindWeatherException(ex);
}
}
private static class ResultObject
{
public QueryObject query;
}
private static class ResultArray
{
public QueryArray query;
}
private static class QueryObject
{
public int count;
public String created;
public String lang;
public ResultsObject results;
}
private static class QueryArray
{
public int count;
public String created;
public String lang;
public ResultsArray results;
}
private static class ResultsObject
{
public Place place;
}
private static class ResultsArray
{
public Place[] place;
}
private static class Place
{
public int woeid;
}
}
CantFindWeatherException.java:
/**
*
* #author robert
*/
public class CantFindWeatherException extends Exception
{
public CantFindWeatherException()
{
}
public CantFindWeatherException(String message)
{
super(message);
}
public CantFindWeatherException(String message, Throwable cause)
{
super(message, cause);
}
public CantFindWeatherException(Throwable cause)
{
super(cause);
}
}
As for the first question, I've build a website using forecast.io. It's pretty good. Good API and 1000 free calls/day. It uses latitute/longitude to find the weather of a place.
As for the second question, I would resolve what the user puts in with the Google Geocoding Api. So when they search for "New York", you check if you already have the relevant coordinates in your database, otherwise, you do an API call to Google Geocoding.
Related
I have to generate documents in my Java Web application (Maven, runs on a server) and have to insert data from a Java class into this document.
I would like to be able to write a HTML file with placeholders. The placeholder should be replaced from the application with data from a Java class.
I also would like to be able to use conditionals like *ngFor (e.g. inserting a list into a ) or *ngIf from Angular (or attributes with a similar function).
Does anyone know a library for this?
I have a good knowledge of Java, HTML etc. so using such a library (if there is one) will not be a problem for me
In the meantime I've written a little script myself. In case someone needs something similar, I've included it in an answer
In the meantime I have searched further and unfortunately I have not found a suitable solution so far. Therefore, I have now set about programming a solution myself. Much less effort is required than expected. Here is my current code. It is currently a rough draft and certainly needs some improvement.
package com.XYZ.file.bo;
import java.beans.IntrospectionException;
import java.beans.PropertyDescriptor;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.InputStream;
import java.io.StringWriter;
import java.lang.reflect.InvocationTargetException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Attr;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import com.XYZ.file.service.FileService;
import com.XYZ.servicelocator.ServiceLocator;
import com.XYZ.util.TechnicalException;
import com.itextpdf.html2pdf.ConverterProperties;
import com.itextpdf.html2pdf.HtmlConverter;
public class TemplateGeneratorBO {
private FileService fileService;
private static final String DOC_TEMPLATE_DIR = FileBO.BASE_DIR + "templates/";
public File generateDoc(String tempFileName, String saveFolder, String saveFileName, Object entity) {
String htmlDoc = parseHtmlDoc(tempFileName, entity);
htmlDoc = replaceSpecialChars(htmlDoc);
ByteArrayOutputStream outStream = new ByteArrayOutputStream();
ConverterProperties converterProperties = new ConverterProperties();
HtmlConverter.convertToPdf(htmlDoc, outStream, converterProperties);
InputStream inStream = new ByteArrayInputStream(outStream.toByteArray());
saveFolder += "/" + callGetter(entity, "id") + "/templates";
if (!getFileService().createAndSaveFile(saveFolder, saveFileName + ".pdf", inStream)) {
int counter = 0;
boolean success = false;
do {
counter++;
success = getFileService().createAndSaveFile(saveFolder, saveFileName + "-" + counter + ".pdf",
inStream);
} while (!success);
return getFileService().getFile(saveFolder, saveFileName + "-" + counter + ".pdf");
}
return getFileService().getFile(saveFolder, saveFileName + ".pdf");
}
private String parseHtmlDoc(String fileName, Object entity) {
try {
File htmlFile = new File(DOC_TEMPLATE_DIR + fileName);
DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
Document doc = dBuilder.parse(htmlFile);
doc.getDocumentElement().normalize();
Element elm = doc.getDocumentElement();
NodeList headList = elm.getElementsByTagName("head");
NodeList bodyList = elm.getElementsByTagName("body");
verifyTemplate(fileName, elm, headList, bodyList);
Node head = headList.item(0);
String html = "<html>" + xmlToString(head) + "<body>";
html += nodeToString(bodyList.item(0),
newTempEntList(new TemplateGenEntity(entity.getClass().getSimpleName(), entity)));
html += "</body></html>";
return html;
} catch (Exception exc) {
throw new TechnicalException("DocGenerator Exception with file " + fileName, exc);
}
}
private String nodeToString(Node parentNode, List<TemplateGenEntity> entities)
throws TransformerException, ScriptException {
NodeList nodes = parentNode.getChildNodes();
StringBuilder string = new StringBuilder("");
for (int i = 0; i < nodes.getLength(); i++) {
Node node = nodes.item(i);
if (node.getNodeType() == Node.ELEMENT_NODE) {
Element elm = (Element) node;
string.append(elementToString(elm, entities));
} else {
string.append(insertValues(xmlToString(node), entities));
}
}
return string.toString();
}
private String elementToString(Element elm, List<TemplateGenEntity> entities)
throws ScriptException, TransformerException {
if (!proofNgIf(elm, entities)) {
return "";
}
if (elm.hasAttribute("ngFor")) {
return ngForElementToString(elm, entities);
}
return "<" + elm.getNodeName() + getElementAttributes(elm) + ">" + nodeToString(elm, entities) + "</"
+ elm.getNodeName() + ">";
}
#SuppressWarnings("unchecked")
private String ngForElementToString(Element elm, List<TemplateGenEntity> entities)
throws ScriptException, TransformerException {
String attrs = getElementAttributes(elm);
String ngFor = elm.getAttribute("ngFor");
String[] ngForList = ngFor.split(" of ");
StringBuilder string = new StringBuilder();
ScriptEngineManager factory = new ScriptEngineManager();
ScriptEngine engine = factory.getEngineByName("JavaScript");
for (TemplateGenEntity ent : entities) {
engine.put(ent.getEntityName(), ent.getEntity());
}
List<Object> list = (List<Object>) engine.eval(ngForList[1]);
for (Object obj : list) {
string.append("<" + elm.getNodeName() + attrs + ">"
+ nodeToString(elm, newTempEntList(entities, new TemplateGenEntity(ngForList[0], obj))) + "</"
+ elm.getNodeName() + ">");
}
return string.toString();
}
/**
*
* #return true if no ngIf or ngIf condition is true
* #throws ScriptException
*/
private boolean proofNgIf(Element elm, List<TemplateGenEntity> entities) throws ScriptException {
if (!elm.hasAttribute("ngIf")) {
return true;
}
String ngIf = elm.getAttribute("ngIf");
if (ngIf.isBlank()) {
throw new TechnicalException("Document template contains empty ngIf!");
}
ScriptEngineManager factory = new ScriptEngineManager();
ScriptEngine engine = factory.getEngineByName("JavaScript");
for (TemplateGenEntity ent : entities) {
engine.put(ent.getEntityName(), ent.getEntity());
}
return (boolean) engine.eval(ngIf);
}
private String insertValues(String strIn, List<TemplateGenEntity> entities) throws ScriptException {
StringBuilder str = new StringBuilder(strIn);
int begin = str.indexOf("{{");
int end = str.indexOf("}}") + 2;
while (begin != -1 && end != 1) {
String var = str.substring(begin, end);
var = var.replace("{{", "");
var = var.replace("}}", "");
ScriptEngineManager factory = new ScriptEngineManager();
ScriptEngine engine = factory.getEngineByName("JavaScript");
for (TemplateGenEntity ent : entities) {
engine.put(ent.getEntityName(), ent.getEntity());
}
Object val = engine.eval(var);
String valStr = objectToStr(val);
str = str.replace(begin, end, valStr);
begin = str.indexOf("{{");
end = str.indexOf("}}") + 2;
}
return str.toString();
}
private String xmlToString(Node node) throws TransformerException {
StringWriter writer = new StringWriter();
Transformer transformer = TransformerFactory.newInstance().newTransformer();
transformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
transformer.setOutputProperty(OutputKeys.INDENT, "no");
transformer.setOutputProperty(OutputKeys.DOCTYPE_PUBLIC, "yes");
transformer.transform(new DOMSource(node), new StreamResult(writer));
return writer.toString();
}
private String replaceSpecialChars(String str) {
str = str.replace(">", ">");
return str;
}
private String getElementAttributes(Element elm) {
StringBuilder attrStr = new StringBuilder();
NamedNodeMap attrs = elm.getAttributes();
for (int i = 0; i < attrs.getLength(); i++) {
Attr attr = (Attr) attrs.item(i);
String attrName = attr.getName();
String attrVal = attr.getValue();
if (attrName.equals("ngIf") || attrName.equals("ngFor")) {
continue;
}
attrStr.append(" " + attrName + "=\"" + attrVal + "\"");
}
return attrStr.toString();
}
private void verifyTemplate(String fileName, Element elm, NodeList head, NodeList body) {
if (!elm.getNodeName().equalsIgnoreCase("html")) {
throw new TechnicalException("Document template " + fileName + " doesn't starts with html node!");
}
if (head.getLength() != 1 || head.item(0) == null) {
throw new TechnicalException("Document template " + fileName + " doesn't contains head!");
}
if (body.getLength() != 1 || head.item(0) == null) {
throw new TechnicalException("Document template " + fileName + " doesn't contains body!");
}
}
private FileService getFileService() {
if (fileService == null) {
fileService = ServiceLocator.locateService(FileService.class);
}
return fileService;
}
private Object callGetter(Object obj, String fieldName) {
PropertyDescriptor pd;
try {
pd = new PropertyDescriptor(fieldName, obj.getClass());
return pd.getReadMethod().invoke(obj);
} catch (IntrospectionException | IllegalAccessException | IllegalArgumentException
| InvocationTargetException e) {
throw new TechnicalException(e.getMessage(), e);
}
}
private String objectToStr(Object obj) {
if (obj instanceof Date) {
return new SimpleDateFormat("dd.MM.yyyy").format(obj);
}
return obj.toString();
}
public static List<TemplateGenEntity> newTempEntList(TemplateGenEntity entity) {
List<TemplateGenEntity> list = new ArrayList<>();
list.add(entity);
return list;
}
public static List<TemplateGenEntity> newTempEntList(List<TemplateGenEntity> entities, TemplateGenEntity entity) {
List<TemplateGenEntity> list = new ArrayList<>();
for (TemplateGenEntity ent : entities) {
list.add(ent);
}
list.add(entity);
return list;
}
public class TemplateGenEntity {
private String entityName;
private Object entity;
public TemplateGenEntity(String entityName, Object entity) {
this.entityName = entityName;
this.entity = entity;
}
public String getEntityName() {
return entityName;
}
public void setEntityName(String entityName) {
this.entityName = entityName;
}
public Object getEntity() {
return entity;
}
public void setEntity(Object entity) {
this.entity = entity;
}
}
}
use freemarker for the placeholder replacement and pd4ml for the html convertion, it works well for me.
I'm trying to write a code to get the latitude and longitude of a user inputted city.
I've written a code which searches a website and then stores its HTML data in a string.
I now want to search the string(the HTML of the website) for the values.
I've looked into API's, and HTML parsers, but they are all too complicated for me (I'm still in school, just starting out), so please don't recommend those unless its absolutely impossible to do without them.
Code:
import java.net.*;
import java.io.*;
import java.util.Scanner;
import static java.lang.System.*;
class websearch {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
//gets the city
out.println("enter city, add plus between multiple words");
String term = sc.nextLine();
try {URL url = new URL("http://www.geonames.org/search.html?q=" + term + "&country=");
URLConnection ucl = url.openConnection();
InputStream stream = ucl.getInputStream();
int i;
//the string in which the html code will be stored
String code = " ";
while ((i=stream.read())!= -1) {
code += Character.toString((char)i);
}
//printing the html, only for testing
System.out.print(code);
} catch(Exception e) {
System.out.println("error");
}
}
}
This code prints a string too large to be pasted here, but the values I want to find look like this:
<td nowrap="">N 40° 42' 51''</td>
<td nowrap="">W 74° 0' 21''</td>
How could I find this sequence of characters, and then store only the latitude and longitude in a variable?
This tutorial should be of some use to you. it goes over how to get the geocode data without actually using the google maps API. If you follow what it says, you should have a fairly easy time implementing it.
The end result is that you will enter the street address of the location you want, and it will return the latitude and longitude in searchable variables.
Primary working class
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.HashMap;
import java.util.Map;
import org.apache.log4j.Logger;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.JSONValue;
import org.json.simple.parser.JSONParser;
public class OpenStreetMapUtils {
public final static Logger log = Logger.getLogger("OpenStreeMapUtils");
private static OpenStreetMapUtils instance = null;
private JSONParser jsonParser;
public OpenStreetMapUtils() {
jsonParser = new JSONParser();
}
public static OpenStreetMapUtils getInstance() {
if (instance == null) {
instance = new OpenStreetMapUtils();
}
return instance;
}
private String getRequest(String url) throws Exception {
final URL obj = new URL(url);
final HttpURLConnection con = (HttpURLConnection) obj.openConnection();
con.setRequestMethod("GET");
if (con.getResponseCode() != 200) {
return null;
}
BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));
String inputLine;
StringBuffer response = new StringBuffer();
while ((inputLine = in.readLine()) != null) {
response.append(inputLine);
}
in.close();
return response.toString();
}
public Map<String, Double> getCoordinates(String address) {
Map<String, Double> res;
StringBuffer query;
String[] split = address.split(" ");
String queryResult = null;
query = new StringBuffer();
res = new HashMap<String, Double>();
query.append("http://nominatim.openstreetmap.org/search?q=");
if (split.length == 0) {
return null;
}
for (int i = 0; i < split.length; i++) {
query.append(split[i]);
if (i < (split.length - 1)) {
query.append("+");
}
}
query.append("&format=json&addressdetails=1");
log.debug("Query:" + query);
try {
queryResult = getRequest(query.toString());
} catch (Exception e) {
log.error("Error when trying to get data with the following query " + query);
}
if (queryResult == null) {
return null;
}
Object obj = JSONValue.parse(queryResult);
log.debug("obj=" + obj);
if (obj instanceof JSONArray) {
JSONArray array = (JSONArray) obj;
if (array.size() > 0) {
JSONObject jsonObject = (JSONObject) array.get(0);
String lon = (String) jsonObject.get("lon");
String lat = (String) jsonObject.get("lat");
log.debug("lon=" + lon);
log.debug("lat=" + lat);
res.put("lon", Double.parseDouble(lon));
res.put("lat", Double.parseDouble(lat));
}
}
return res;
}
}
How to call the above working class:
public class GetCoordinates {
static String address = "The White House, Washington DC";
public static void main(String[] args) {
Map<String, Double> coords;
coords = OpenStreetMapUtils.getInstance().getCoordinates(address);
System.out.println("latitude :" + coords.get("lat"));
System.out.println("longitude:" + coords.get("lon"));
}
}
use XPath is a easy way.
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document doc = builder.parse(<uri_as_string>);
XPathFactory xPathfactory = XPathFactory.newInstance();
XPath xpath = xPathfactory.newXPath();
XPathExpression expr = xpath.compile(<xpath_expression>);
as for , try something like below:
/xxx/td[#nowrap='']/text()
I'm building a simple currency converter which needs to sue online rates. I found the following API from the European Central Bank to use:
http://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml
My problem is im struggling to implement it. Here is what i have so far after using a bunch of different sources to try and get this code together.
try{
URL url = new URL("http://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml");
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document doc = db.parse(new InputSource(url.openStream()));
doc.getDocumentElement().normalize();
NodeList nodeList1 = doc.getElementsByTagName("Cube");
for(int i = 0; i < nodeList1.getLength(); i++){
Node node = nodeList1.item(i);
}
}
catch(Exception e){
}
So what i thought is that this code would take down all the nodes which tart with "Cube", and contain the rates.
Anyone have an easier wya to pull down the rates from the API into an array in the order they appear on the XML as that's all I'm trying to do
Thanks
XPath is one way to answer this, since you just want to extract information from the XML and not change the XML. The structure of the XML suggests that you're looking for nodes that are Cube nodes, that are child of Cube which is also a child of Cube -- Cube nested three times, so extract nodes with an XPath compiled using this String: "//Cube/Cube/Cube". This looks for nodes that have Cube nested 3 times located anywhere (the //) in the Document:
XPathExpression expr = xpath.compile("//Cube/Cube/Cube");
Then check the nodes for a "currency" attribute. If they have this, then they also have a "rate" attribute, and then extract this information.
NamedNodeMap attribs = node.getAttributes();
if (attribs.getLength() > 0) {
Node currencyAttrib = attribs.getNamedItem(CURRENCY);
if (currencyAttrib != null) {
String currencyTxt = currencyAttrib.getNodeValue();
String rateTxt = attribs.getNamedItem(RATE).getNodeValue();
// ...
}
}
Where CURRENCY = "currency" and RATE = "rate"
For example:
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
import javax.xml.parsers.*;
import javax.xml.xpath.*;
import org.w3c.dom.Document;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;
public class TestXPath {
private static final String CURRENCY = "currency";
private static final String CUBE_NODE = "//Cube/Cube/Cube";
private static final String RATE = "rate";
public static void main(String[] args) {
List<CurrencyRate> currRateList = new ArrayList<>();
DocumentBuilderFactory builderFactory =
DocumentBuilderFactory.newInstance();
DocumentBuilder builder = null;
try {
builder = builderFactory.newDocumentBuilder();
} catch (ParserConfigurationException e) {
e.printStackTrace();
}
Document document = null;
String spec = "http://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml";
try {
URL url = new URL(spec);
InputStream is = url.openStream();
document = builder.parse(is);
XPathFactory xPathfactory = XPathFactory.newInstance();
XPath xpath = xPathfactory.newXPath();
String xPathString = CUBE_NODE;
XPathExpression expr = xpath.compile(xPathString);
NodeList nl = (NodeList) expr.evaluate(document, XPathConstants.NODESET);
for (int i = 0; i < nl.getLength(); i++) {
Node node = nl.item(i);
NamedNodeMap attribs = node.getAttributes();
if (attribs.getLength() > 0) {
Node currencyAttrib = attribs.getNamedItem(CURRENCY);
if (currencyAttrib != null) {
String currencyTxt = currencyAttrib.getNodeValue();
String rateTxt = attribs.getNamedItem(RATE).getNodeValue();
currRateList.add(new CurrencyRate(currencyTxt, rateTxt));
}
}
}
} catch (SAXException | IOException | XPathExpressionException e) {
e.printStackTrace();
}
for (CurrencyRate currencyRate : currRateList) {
System.out.println(currencyRate);
}
}
}
public class CurrencyRate {
private String currency;
private String rate; // ?double
public CurrencyRate(String currency, String rate) {
super();
this.currency = currency;
this.rate = rate;
}
public String getCurrency() {
return currency;
}
public String getRate() {
return rate;
}
#Override
public String toString() {
return "CurrencyRate [currency=" + currency + ", rate=" + rate + "]";
}
// equals, hashCode,....
}
every one knows we can traverse entire xml document using DocumentTraversal's NodeIterator.
my application require some extra work so i decided to write my own XML traverser with the support of java Stack<>.
here is my code (i am not good at coding so the code and logic might look messy).
public class test
{
private static Stack<Node> gStack = new Stack<Node>();
public static void main(String[] args) throws XPathExpressionException
{
String str =
"<section>"
+ "<paragraph>This example combines regular wysiwyg editing of a document with very controlled editing of semantic rich content. The main content can be"
+ "edited like you would in a normal word processor. Though the difference is that the content remains schema valid XML because Xopus will not allow you to perform actions"
+ "on the document that would render it invalid.</paragraph>"
+ "<paragraph>The table is an example of controlled style. The style of the table is controlled by three attributes:</paragraph>"
+ "<unorderedlist>"
+ "<item><paragraph><emphasis>alternaterowcolor</emphasis>, do all rows have the same color, or should the background color alternate?</paragraph></item>"
+ "<item><paragraph><emphasis>border</emphasis>, a limited choice of border styles.</paragraph></item>"
+ "<item><paragraph><emphasis>color</emphasis>, a limited choice of colors.</paragraph></item>"
+ "</unorderedlist>"
+ "<paragraph>You have quite some freedom to style the table, but you can't break the predefined style.</paragraph>"
+ "</section>";
Document domDoc = null;
try
{
DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder docBuilder = docFactory.newDocumentBuilder();
ByteArrayInputStream bis = new ByteArrayInputStream(str.getBytes());
domDoc = docBuilder.parse(bis);
}
catch (Exception e)
{
e.printStackTrace();
}
Element root = null;
NodeList list = domDoc.getChildNodes();
for (int i = 0; i < list.getLength(); i++)
{
if (list.item(i) instanceof Element)
{
root = (Element) list.item(i);
break;
}
}
NodeList nlist = root.getChildNodes();
System.out.println("root = " + root.getNodeName() + " child count = " + nlist.getLength());
domTraversor(root);
}
private static void domTraversor(Node node)
{
if (node.getNodeName().equals("#text"))
{
System.out.println("textElem = " + node.getTextContent());
if (node.getNextSibling() != null)
{
gStack.push(node.getNextSibling());
domTraversor(node.getNextSibling());
}
else
{
if (node.getParentNode().getNextSibling() != null)
domTraversor(node.getParentNode().getNextSibling());
}
}
else
{
if (node.getChildNodes().getLength() > 1)
{
gStack.push(node);
Node n = node.getFirstChild();
if (n.getNodeName().equals("#text"))
{
System.out.println("textElem = " + n.getTextContent());
if (n.getNextSibling() != null)
{
gStack.push(n.getNextSibling());
domTraversor(n.getNextSibling());
}
}
else
{
gStack.push(n);
domTraversor(n);
}
}
else if (node.getChildNodes().getLength() == 1)
{
Node fnode = node.getFirstChild();
if (fnode.getChildNodes().getLength() > 1)
{
gStack.push(fnode);
domTraversor(fnode);
}
else
{
if (!fnode.getNodeName().equals("#text"))
{
gStack.push(fnode);
domTraversor(fnode);
}
else
{
System.out.println("textElem = " + fnode.getTextContent());
if (fnode.getNodeName().equals("#text"))
{
if (node.getNextSibling() != null)
{
gStack.push(node.getNextSibling());
domTraversor(node.getNextSibling());
}
else
{
if (!gStack.empty())
{
Node sibPn = gStack.pop();
if (sibPn.getNextSibling() == null)
{
sibPn = gStack.pop();
}
domTraversor(sibPn.getNextSibling());
}
}
}
else
{
if (fnode.getNextSibling() != null)
{
domTraversor(fnode.getNextSibling());
}
else
{
if (!gStack.empty())
{
Node sibPn = gStack.pop().getNextSibling();
domTraversor(sibPn);
}
}
}
}
}
}
}
}
}
and it is working fine with some xml document, but not with the document which has tag like.
<unorderedlist>
<item>
<paragraph>
<emphasis>alternaterowcolor</emphasis>
, do all rows have the same color, or should the background
color
alternate?
</paragraph>
</item>
<item>
<paragraph>
<emphasis>border</emphasis>
, a limited choice of border styles.
</paragraph>
</item>
<item>
<paragraph>
<emphasis>color</emphasis>
, a limited choice of colors.
</paragraph>
</item>
</unorderedlist>
here is the scenario if any element has more than three nested children my code get stopped and not going further.
is there any one has a better implementation, please suggest.
try this way
Element e;
NodeList n;
Document doc=StudyParser.XMLfromString(xmlString);
String starttag=doc.getFirstChild().getNodeName();
Log.e("start",starttag );
n=doc.getElementsByTagName(starttag);
for(int i=0;i<n.getLength();i++){
e=(Element)n.item(i);
NodeList np = e.getElementsByTagName("item");
for(int j=0;j<np.getLength();j++){
e=(Element)n.item(i);
try{
String para=StudyParser.getValue(e, "paragraph");
Log.e("paravalue",para);
String emp=StudyParser.getValue(e, "emphasis");
Log.e("empval",emp);
}catch(Exception e){
e.printStackTrace();
}
}
}
StudyParser Class
import java.io.BufferedInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.StringReader;
import java.io.UnsupportedEncodingException;
import java.net.MalformedURLException;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
public class StudyParser {
public StudyParser() {
}
public final static Document XMLfromString(String xml){
Document doc = null;
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
try {
DocumentBuilder db = dbf.newDocumentBuilder();
InputSource is = new InputSource();
is.setCharacterStream(new StringReader(xml));
doc = db.parse(is);
} catch (ParserConfigurationException e) {
System.out.println("XML parse error: " + e.getMessage());
return null;
} catch (SAXException e) {
System.out.println("Wrong XML file structure: " + e.getMessage());
return null;
} catch (IOException e) {
System.out.println("I/O exeption: " + e.getMessage());
return null;
}
return doc;
}
public static String getXMLstring(String xml){
String line = null;
try {
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(xml);
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
line = EntityUtils.toString(httpEntity);
} catch (UnsupportedEncodingException e) {
line = "<results status=\"error\"><msg>Can't connect to server</msg></results>";
} catch (MalformedURLException e) {
line = "<results status=\"error\"><msg>Can't connect to server</msg></results>";
} catch (IOException e) {
line = "<results status=\"error\"><msg>Can't connect to server</msg></results>";
}
return line;
}
public static String getXML(InputStream is)throws IOException {
BufferedInputStream bis = new BufferedInputStream(is);
ByteArrayOutputStream buf = new ByteArrayOutputStream();
int result = bis.read();
while(result != -1) {
byte b = (byte)result;
buf.write(b);
result = bis.read();
}
return buf.toString();
}
public final static String getElementValue( Node elem ) {
Node kid;
if( elem != null){
if (elem.hasChildNodes()){
for( kid = elem.getFirstChild(); kid != null; kid = kid.getNextSibling() ){
if( kid.getNodeType() == Node.TEXT_NODE ){
return kid.getNodeValue();
}
}
}
}
return "";
}
public static int numResults(Document doc){
Node results = doc.getDocumentElement();
int res = -1;
try{
res = Integer.valueOf(results.getAttributes().getNamedItem("Categories").getNodeValue());
}catch(Exception e ){
res = -1;
}
return res;
}
public static String getValue(Element item, String str) {
NodeList n = item.getElementsByTagName(str);
return StudyParser.getElementValue(n.item(0));
}
}
Just Normal demo for dynamic xml i have assumed the same xml and but without using getElementByTagName there are many properties you can check accodringlly see
doc = StudyParser.XMLfromString(xml);
String starttag=doc.getFirstChild().getNodeName();
Log.e("start",starttag );
n=doc.getElementsByTagName(starttag);
for(int i=0;i<n.getLength();i++){
e=(Element)n.item(i);
try{
Log.e("1234",""+ e.getTextContent());
}catch(Exception e){
e.printStackTrace();
}
}
this is my xml :
<-tobject.subject tobject.subject.refnum="01016000" />
<-tobject.subject tobject.subject.refnum="10004000" />
I want to extract 01016000 and 10004000 from it .
I used this code:
NodeList nodeLst4 = doc.getElementsByTagName("tobject.subject");
if (nodeLst4 != null) {
int numberofCOdes = nodeLst4.getLength();
aSubjectCodes = new String[numberofCOdes];
for (int i = 0; i < numberofCOdes; i++) {
XPath xpath = XPathFactory.newInstance().newXPath();
aSubjectCodes[i] = xpath.evaluate("//tobject.subject/#tobject.subject.refnum", doc);
the problem is that when i loop through it the evaluate method just return first number and do not give me the second value.
and i am not sure if using xpath.evaluate is good idea or not.
Thanks
there is no need to use the doc.getElementsByTagName.
You are mixing plain DOM with XPath.
Your xpath is correct:
package net.davymeers;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.Collection;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;
import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;
public class XpathTest {
private static String XMLSTRING = "<data>"
+ "<tobject.subject tobject.subject.refnum=\"01016000\" />\r\n"
+ "\r\n"
+ "<tobject.subject tobject.subject.refnum=\"10004000\" />"
+ "</data>";
/**
* #param args
*/
public static void main(final String[] args) {
final Document doc = createDocument();
final XPath xpath = createXpath();
final NodeList nodes = findElements(
"//tobject.subject/#tobject.subject.refnum", doc, xpath);
final Collection<String> results = convertToCollection(nodes);
for (final String result : results) {
System.out.println(result);
}
}
private static Document createDocument() {
Document doc = null;
try {
final DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory
.newInstance();
documentBuilderFactory.setNamespaceAware(true); // never forget
// this!
final DocumentBuilder builder = documentBuilderFactory
.newDocumentBuilder();
doc = builder.parse(new ByteArrayInputStream(XMLSTRING
.getBytes("ISO-8859-1")));
} catch (final UnsupportedEncodingException exception) {
// TODO handle exception
} catch (final SAXException exception) {
// TODO handle exception
} catch (final IOException exception) {
// TODO handle exception
} catch (final ParserConfigurationException exception) {
// TODO handle exception
}
return doc;
}
private static XPath createXpath() {
final XPathFactory xpathFactory = XPathFactory.newInstance();
final XPath xpath = xpathFactory.newXPath();
return xpath;
}
private static NodeList findElements(final String xpathExpression,
final Document doc, final XPath xpath) {
NodeList nodes = null;
if (doc != null) {
try {
final XPathExpression expr = xpath.compile(xpathExpression);
final Object result = expr
.evaluate(doc, XPathConstants.NODESET);
nodes = (NodeList) result;
} catch (final XPathExpressionException exception) {
// TODO handle exception
}
}
return nodes;
}
private static Collection<String> convertToCollection(final NodeList nodes) {
final Collection<String> result = new ArrayList<String>();
if (nodes != null) {
for (int i = 0; i < nodes.getLength(); i++) {
result.add(nodes.item(i).getNodeValue());
}
}
return result;
}
}
Here's a useful class I found a while back for XMLFiles. Takes a lot of the work off of your shoulders.
import java.io.FileInputStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
/**
* XMLFile.java
*
* XML file object that represents an xml file and its properties. Used to
* simplify the process of reading from and writing to XML files.
*
* Derived from unknown source. Implemented on 12/03/09. Permission given to
* implement and modify code.
*/
public class XMLFile {
private String name;
private String content;
private Map<String, String> nameAttributes = new HashMap<String, String>();
private Map<String, List<XMLFile>> nameChildren = new HashMap<String, List<XMLFile>>();
private static Element rootElement(String filename, String rootName) {
FileInputStream fileInputStream = null;
try {
fileInputStream = new FileInputStream(filename);
DocumentBuilderFactory builderFactory = DocumentBuilderFactory
.newInstance();
DocumentBuilder builder = builderFactory.newDocumentBuilder();
Document document = builder.parse(fileInputStream);
Element rootElement = document.getDocumentElement();
if (!rootElement.getNodeName().equals(rootName))
throw new RuntimeException("Could not find root node: "
+ rootName);
return rootElement;
} catch (Exception exception) {
throw new RuntimeException(exception);
} finally {
if (fileInputStream != null) {
try {
fileInputStream.close();
} catch (Exception exception) {
throw new RuntimeException(exception);
}
}
}
}
/**
* #param (String) Filepath of XML File (String) Root of XML File
**/
public XMLFile(String filename, String rootName) {
this(rootElement(filename, rootName));
}
/**
* #param (Element) XML File Element
**/
private XMLFile(Element element) {
this.name = element.getNodeName();
this.content = element.getTextContent();
NamedNodeMap namedNodeMap = element.getAttributes();
int n = namedNodeMap.getLength();
for (int i = 0; i < n; i++) {
Node node = namedNodeMap.item(i);
String name = node.getNodeName();
addAttribute(name, node.getNodeValue());
}
NodeList nodes = element.getChildNodes();
n = nodes.getLength();
for (int i = 0; i < n; i++) {
Node node = nodes.item(i);
int type = node.getNodeType();
if (type == Node.ELEMENT_NODE)
addChild(node.getNodeName(), new XMLFile((Element) node));
}
}
/**
* Adds attribute to ???
*
* #param (String) Attribute Name (String) Attribute Value
**/
private void addAttribute(String name, String value) {
nameAttributes.put(name, value);
}
/**
* Adds child directory to ???
*
* #param (String) Name of New Child Directory (XMLFile) XML Documentation
* of Child
**/
private void addChild(String name, XMLFile child) {
List<XMLFile> children = nameChildren.get(name);
if (children == null) {
children = new ArrayList<XMLFile>();
nameChildren.put(name, children);
}
children.add(child);
}
public String name() {
return name;
}
public String content() {
return content;
}
/**
*
**/
public XMLFile child(String name) {
List<XMLFile> children = children(name);
if (children.size() != 1)
throw new RuntimeException("Could not find individual child node: "
+ name);
return children.get(0);
}
/**
*
**/
public List<XMLFile> children(String name) {
List<XMLFile> children = nameChildren.get(name);
return children == null ? new ArrayList<XMLFile>() : children;
}
/**
* Gets the value of a specific field and converts it to a String object
*
* #param (String) Name of Field
**/
public String string(String name) {
String value = nameAttributes.get(name);
if (value == null)
throw new RuntimeException("Could not find attribute: " + name
+ ", in node: " + this.name);
return value;
}
/**
* Gets the value of a specific field and converts it to an int
*
* #param (String) Name of Field
**/
public int integer(String name) {
return Integer.parseInt(string(name));
}
/**
* Gets the value of a specific field and converts it to an
* ArrayList<String>
*
* #param (String) Name of Field
**/
public ArrayList<String> arrayListString(String name) {
String left = new String();
int finished = 0;
ArrayList<String> list = new ArrayList<String>();
try {
left = nameAttributes.get(name);
} catch (Exception e) {
System.err.println("Exception: " + e.getMessage());
}
while (finished == 0) {
if (left.indexOf(", ") > -1) {
list.add(left.substring(0, left.indexOf(", ")));
left = left.substring(left.indexOf(", ") + 2);
} else {
list.add(left);
finished = 1;
}
}
return list;
}
}
Would this work for you? I am parsing RSS XML from here:
http://www.kraftfoods.com/rss/dinnerRecipes.aspx
Look at Media and URL towards the bottom:
package recipeSearchAndFinder.xml;
import java.util.ArrayList;
import java.util.List;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
public class DomFeedParser extends BaseFeedParser {
public DomFeedParser(String feedUrl) {
super(feedUrl);
}
public List<Message> parse() {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
List<Message> messages = new ArrayList<Message>();
try {
DocumentBuilder builder = factory.newDocumentBuilder();
Document dom = builder.parse(this.getInputStream());
Element root = dom.getDocumentElement();
NodeList items = root.getElementsByTagName(ITEM);
for (int i = 0; i < items.getLength(); i++) {
Message message = new Message();
Node item = items.item(i);
NodeList properties = item.getChildNodes();
for (int j = 0; j < properties.getLength(); j++) {
Node property = properties.item(j);
String name = property.getNodeName();
if (name.equalsIgnoreCase(TITLE)) {
message.setTitle(property.getFirstChild()
.getNodeValue());
} else if (name.equalsIgnoreCase(LINK)) {
message.setLink(property.getFirstChild().getNodeValue());
} else if (name.equalsIgnoreCase(DESCRIPTION)) {
StringBuilder text = new StringBuilder();
NodeList chars = property.getChildNodes();
for (int k = 0; k < chars.getLength(); k++) {
text.append(chars.item(k).getNodeValue());
}
message.setDescription(text.toString());
} else if (name.equalsIgnoreCase(PUB_DATE)) {
message.setDate(property.getFirstChild().getNodeValue());
} else if (name.equalsIgnoreCase(MEDIA)) {
NamedNodeMap nMap = property.getAttributes();
String mediaurl = nMap.getNamedItem("url")
.getNodeValue();
message.setMedia(mediaurl);
}
}
messages.add(message);
}
} catch (Exception e) {
throw new RuntimeException(e);
}
return messages;
}
}