We Keep Coding

Appending XML data to an ArrayList

I have created an XML parser to retrieve the information from an XML file to java, and then I am trying to store these data into an ArrayList in order to use the ArrayList for my methods.
It seems to work fine when I print it. However, I got a method called getAllRoutes for some reason it returns the wrong number of routes

Please move
routes.add(r);
inside
if (c.getNodeName().equals("Route")) {

Let me know if this helps Khaled.
Try this:
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathFactory;
import javax.xml.xpath.XPathExpressionException;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.List;
import java.util.ArrayList;
class Main {
public static Iterable<Node> iterable(final NodeList nodeList) {
return () -> new Iterator<Node>() {
private int index = 0;
#Override
public boolean hasNext() {
return index < nodeList.getLength();
}
#Override
public Node next() {
if (!hasNext())
throw new NoSuchElementException();
return nodeList.item(index++);
}
};
}
private static List<String> evaluateXPath(Document document, String xpathExpression)
{
// Create XPathFactory object
XPathFactory xpathFactory = XPathFactory.newInstance();
// Create XPath object
XPath xpath = xpathFactory.newXPath();
List<String> values = new ArrayList<>();
try
{
// Create XPathExpression object
XPathExpression expr = xpath.compile(xpathExpression);
// Evaluate expression result on XML document
NodeList nodes = (NodeList) expr.evaluate(document, XPathConstants.NODESET);
for (int i = 0; i < nodes.getLength(); i++) {
values.add(nodes.item(i).getNodeValue());
}
} catch (XPathExpressionException e) {
e.printStackTrace();
}
return values;
}
public static void main(String[] args) throws Exception {
//Build DOM
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setNamespaceAware(true); // never forget this!
DocumentBuilder builder = factory.newDocumentBuilder();
Document doc = builder.parse("data.xml");
//Create XPath
XPathFactory xpathfactory = XPathFactory.newInstance();
XPath xpath = xpathfactory.newXPath();
String xpathRoot = "//Routes/Route";
XPathExpression expr = xpath.compile(xpathRoot);
int i = 0;
for (Node n : iterable((NodeList) expr.evaluate(doc, XPathConstants.NODESET))) {
i++;
String xpe2 = String.format("%s[%d]/%s/text()", xpathRoot, i, "FlightNumber");
System.out.println("FxPe: " + xpe2);
System.out.println("Flight Number: " + evaluateXPath(doc, xpe2).get(0));
for (Node n2 : iterable(n.getChildNodes())) {
System.out.println(n2.getTextContent());
}
}
}
}
See it in action here
Useful links:
1: Iterate through NodeList
2: XPath CheatSheet
3: Java XPath Example a and b
4: NodeList Java docs
5: Node Java docs
And I would say. I your code:
Route r = new Route(); should be inside if statement
if (c.getNodeName().equals("Route"))
The commented out add is in the right place - the other place is wrong.

How to read an online XML file for currency rates in java

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,....
}

How to get Tag name with normal core java

My Text File:
hibernate-mapping
class name="EmployeeMaster" table="EmployeeMASTER"
id name="empid" type="java.lang.String"
column name="EMPAID"
generator class="assigned"
/generator
/id
/class
/hibernate-mapping
My Expecting Output:
hibernate-mapping
class
id
/id
/class
/hibernate-mapping

Following is the code that do this simply without apis/standard parsers.
File fXmlFile = new File("F:\\Test.hbm.xml");
FileInputStream fis = new FileInputStream(fXmlFile);
String fileContent = "";
while(fis.available() > 0){
fileContent += (char)fis.read();
}
String[] lines = fileContent.split("\n");
for (String string : lines) {
string = string.trim();
String value="";
if(string.startsWith("<")){
if(string.indexOf(" ") == -1)
value = string;
else
value = string.substring(0, string.indexOf(" "));
}
value = value.replace("<", "").replace(">", "");
System.out.println(value);
}
With the help of parser
import java.io.File;
import java.io.IOException;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;
import com.opshub.exceptions.DataValidationException;
public class Test{
public static void main(String[] args) throws DataValidationException, IOException, ParserConfigurationException, SAXException{
File fXmlFile = new File("F:\\checkouts\\current\\Test.hbm.xml");
DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
org.w3c.dom.Document doc = dBuilder.parse(fXmlFile);
NodeList nodes = doc.getChildNodes();
for(int i=0;i<nodes.getLength();i++){
printElements(nodes.item(i));
}
}
public static void printElements(org.w3c.dom.Node node){
if(node.ELEMENT_NODE != node.getNodeType())
return;
System.out.println(node.getNodeName());
if(node.hasChildNodes()){
for(int i=0;i<node.getChildNodes().getLength();i++){
printElements(node.getChildNodes().item(i));
}
}
System.out.println("/" + node.getNodeName());
}
}

JAVA XML PARSING TO SPLIT XML based on object and class tag elements

This is the JAVA XML i'm parsing..
<objects>
<object>...<class>A /<class>...</object>
<object>...<class>B</class>....</object>
<object>...<class>A /<class>...</object>
</objects>
Now i split the XML into 3 XML's based on object tag with the below code.
DocumentBuilder builder = dbf.newDocumentBuilder();
Document doc = builder.parse("xml");
doc.getDocumentElement().normalize();
TransformerFactory tranFactory = TransformerFactory.newInstance();
Transformer aTransformer = tranFactory.newTransformer();
NodeList list =(NodeList) doc.getElementsByTagName("object");
System.out.println("XML SPLITED");
for (int i=0; i<list.getLength(); i++){
Node element = list.item(i).cloneNode(true);
if(element.hasChildNodes()){
Source src = new DOMSource(element);
FileOutputStream fs=new FileOutputStream("XML" + i + ".xml");
Result dest = new StreamResult(fs);
aTransformer.transform(src, dest);
fs.close();
}
My requirement is to get only the files with class tag A.So my output will be only 2 XML's.Please post your answers.

Using your example, you can do that this way:
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.Result;
import javax.xml.transform.Source;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
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.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;
public class XmlSplitting {
private static final Logger logger = Logger.getLogger(XmlSplitting.class.getName());
private static final String FILE_PATH = "./";
private DocumentBuilder builder;
private Transformer transformer;
public XmlSplitting() throws ParserConfigurationException, TransformerConfigurationException {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
this.builder = factory.newDocumentBuilder();
TransformerFactory transfromerFactory = TransformerFactory.newInstance();
this.transformer = transfromerFactory.newTransformer();
}
public static void main(String[] args) {
try {
XmlSplitting s = new XmlSplitting();
s.run();
} catch (ParserConfigurationException | SAXException | IOException | TransformerException x) {
logger.log(Level.SEVERE, "Error", x);
}
}
private void run() throws ParserConfigurationException, SAXException, IOException, TransformerException {
File file = new File(FILE_PATH + "xml.xml");
if (file.exists()) {
Document document = this.builder.parse(file);
document.normalize();
NodeList list = document.getElementsByTagName("object");
for (int i = 0; i < list.getLength(); i++) {
Node node = list.item(i);
if (Node.ELEMENT_NODE == node.getNodeType()) {
Element object = (Element)node;
NodeList classes = object.getElementsByTagName("class");
if (1 == classes.getLength()) {
Node clazz = classes.item(0);
if (Node.ELEMENT_NODE == clazz.getNodeType()) {
this.copyNodeToNewFile(clazz.getTextContent(), node, i);
}
} else {
logger.log(Level.SEVERE, "Number of class nodes in node object is different than expected. Number of class nodes found: {0}.", classes.getLength());
}
}
}
} else {
logger.log(Level.SEVERE, "You provided wrong path for xml file.");
}
}
private void copyNodeToNewFile(String content, Node node, int i) throws IOException, TransformerException {
boolean copy = this.nodeShouldBeCopied(content);
logger.log(Level.INFO, "Node with content {0} will {1}be moved to separete file.", new Object[]{content, true == copy ? "" : "not "});
if (copy) {
String fileName = String.format("%sxml%d.xml", FILE_PATH, i);
try (FileOutputStream fos = new FileOutputStream(fileName)) {
Source source = new DOMSource(node);
Result destination = new StreamResult(fos);
this.transformer.transform(source, destination);
}
}
}
// here you can change condition to copy given node to file
private boolean nodeShouldBeCopied(String content) {
return content.contains("A");
}
}

How about using a Brazilian framework to parse your XML? it will make your code more exotic and you can tell your friends about it:
http://jcoltrane.sourceforge.net/userguide/extending_parsing_process.html

Regarding XPath using Java

I have a problem in getting the value of an element by providing the XPath using java. I tried lot of things but could not succeed.
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.StringReader;
import java.util.HashMap;
import java.util.Map;
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.NodeList;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import com.dell.logistics.framework.transform.NamespaceContext;
public class GetXPath {
protected Object evaluate(String xpathStr, String xml, String namespaces) throws XPathExpressionException {
InputSource inputSource = new InputSource(new StringReader(xml));
XPathFactory factory = XPathFactory.newInstance();
XPath xPath = factory.newXPath();
NamespaceContext nsContext = new NamespaceContext();
nsContext.setNamespacesMap(getNsMap(namespaces));
//System.out.println(nsContext.getPrefix(namespaces));
xPath.setNamespaceContext(nsContext);
XPathExpression xpExp = xPath.compile(xpathStr);
return xpExp.evaluate(inputSource, XPathConstants.NODESET);
}
private Map<String, String> getNsMap(String namespaces) {
String delims = ",";
String[] nsKeyValue = namespaces.split(delims);
Map<String, String> mp = new HashMap<String, String>();
for (String string : nsKeyValue) {
mp.put(string.split("=")[0], string.split("=")[1]);
System.out.println(string.split("=")[0] + string.split("=")[1]);
}
return mp;
}
public static String readFile(String fileName) {
try {
// InputStream is = null;
InputStream is = GetWorkOrderDataExtractor.class.getResourceAsStream(fileName);
BufferedReader br = new BufferedReader(new InputStreamReader(is));
StringBuffer sb = new StringBuffer();
String l = null;
while ((l = br.readLine()) != null) {
sb.append(l).append("\n");
}
return sb.toString();
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
public static void main(String[] args)
throws ParserConfigurationException, SAXException,
IOException, XPathExpressionException {
GetXPath g = new GetXPath();
String xml = readFile("fooewo.xml");
String value = null;
System.out.println(xml);
NodeList containerNodes = (NodeList) g.evaluate(
"/demo",xml,
"a=http://schemas.demo.com/it/WorkOrderChannelAckNackResponse/1.0");
try{
for (int i = 0; i < containerNodes.getLength(); i++) {
// get the node value.
value = containerNodes.item(i).getTextContent();
System.out.println(value);
}
System.out.println("Node Found : " + containerNodes.getLength() + " times");
}
catch (Exception e)
{
e.printStackTrace();
}
}
}
"
XML file:
<?xml version="1.0" encoding="utf-8"?>
<demo xmlns="try with ur schema">
<test>
<value>10</value>
<color>red</color>
<animal>dog</animal>
<day>13</day>
<age>22</age>
</test>
<test>
<value>20</value>
<color>green</color>
<animal>cat</animal>
<day>12</day>
<age>23</age>
</test>
</demo>
Any help appreciated.
Thanks,
Pradeep

I think the best way to evaluate XPath easily is using AXIOMXPath
Here is an example,
OMElement documentElement = new StAXOMBuilder(inStreamToXML).getDocumentElement();
AXIOMXPath xpathExpression = new AXIOMXPath ("/demo");
List nodeList = (OMNode)xpathExpression.selectNodes(documentElement);
By traversing the list you can get the result easily.