I have XML file like this:
<catalog>
<category>
<books>
<book>
<id>book1</id>
<description>short description</description>
<pages>number of pages</pages>
<author>Anonymous</author>
<name>Book title</name>
</book>
<book>
<id>book2</id>
<description>short description</description>
<pages>number of pages</pages>
<author>Anonymous</author>
<name>Book title</name>
</book>
</books>
</category>
<category>
<books>
<book>
<id>book3</id>
<description>short description</description>
<pages>number of pages</pages>
<author>Anonymous</author>
<name>Book title</name>
</book>
</books>
</category>
</catalog>
And I need an ArrayList with Categories and ArrayList with Books. Here are my Book and Category classes:
public class Book
{
private String id;
private String description;
private String pages;
private String author;
private String name;
}
public class Category {
private ArrayList<Book> books;
private String name;
}
What is the easiest way to do this? Using only android libraries and stuff would be better than using some libraries not for commercial use for my task. I tried some DOM parsers, but it didn't work good.
Actually it can easily be done using dom parser. Here is a stand alone java program to parse your XML file. I am printing values in standard output you can modify it to use in your android application.
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;
import org.w3c.dom.Element;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
public class Main {
public static void main(String[] args) throws IOException, SAXException, ParserConfigurationException {
File fXmlFile = new File("books");
DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
Document doc = dBuilder.parse(fXmlFile);
// iterate through <category> tags
NodeList categoryList = doc.getElementsByTagName("category");
for (int categoryNo=0;categoryNo<categoryList.getLength();categoryNo++) {
Element categoryNode = (Element)categoryList.item(categoryNo);
System.out.println("Category No " +categoryNo);
//iterate through <books> tags
NodeList booksList = categoryNode.getElementsByTagName("books");
for (int booksNo=0;booksNo<booksList.getLength();booksNo++) {
Element books = (Element)booksList.item(0);
// iterate through <book> tags
NodeList bookList = books.getElementsByTagName("book");
for(int bookNo=0;bookNo<bookList.getLength();bookNo++) {
Element bookElement = (Element)bookList.item(bookNo);
System.out.println(bookElement.getElementsByTagName("id").item(0).getTextContent());
System.out.println(bookElement.getElementsByTagName("description").item(0).getTextContent());
System.out.println(bookElement.getElementsByTagName("pages").item(0).getTextContent());
System.out.println(bookElement.getElementsByTagName("author").item(0).getTextContent());
System.out.println(bookElement.getElementsByTagName("name").item(0).getTextContent());
}
}
}
}
}
Have a look at android xml pull parser, this page has examples too
(it is a SAX parser)
Related
My problem is in getting the first child of an XML node using the getFirstChild().
My xml is very basic, as follows :
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<network name="beep">
<layers number="3">
<layer index="0" lenght="3">
...
</layer>
<layer index="1" lenght="3">
...
</layer>
....
</layers>
</network>
Java-code
import org.w3c.dom.*;
import javax.xml.parsers.*;
import java.io.StringReader;
import org.xml.sax.InputSource;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
try {
DocumentBuilderFactory DBF = DocumentBuilderFactory.newInstance();
DocumentBuilder DB = DBF.newDocumentBuilder();
Document doc = DB.parse(new InputSource( new StringReader(Xml)));
doc.getDocumentElement().normalize();
Element root = doc.getDocumentElement();
NodeList Nodes =root.getElementsByTagName("network");
Node Layers = Nodes.item(0).getFirstChild();
}
catch (Exception ex)
{
}
as you can see there is an element which is a child of "network" and it is a "layer".
I can successfully access to the network, getting the list of nodes, which is basically one node, but as soon as I try to get the first child of the first (and only) node with :
Node Layers = Nodes.item(0).getFirstChild();
I get an exception, and, even funnier, the exception is null.
Where's the problem?
Please try below code(both Files):
1) XML File:
_________
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<network name="beep">
<layers number="3">
<layer index="0" lenght="3">Hare</layer>
<layer index="1" lenght="3">Rama</layer>
<layer index="0" lenght="3">Hare</layer>
<layer index="1" lenght="3">Krishna</layer>
</layers>
</network>
**************************************************************
2) Java File:
__________
import java.io.InputStream;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
public class XMLDemo {
public static void main(String...lsdfs) {
DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
try {
InputStream inputStream = XMLDemo.class.getClassLoader().getResourceAsStream("dataFilePackage/XmlData.xml");
DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
Document document = documentBuilder.parse(inputStream);
NodeList nodeList = document.getElementsByTagName("network");
System.out.println(nodeList.item(0).getTextContent());
} catch (Exception e) {
System.out.println(e.getMessage());
}
}
}
I modified your xml to :
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<network name="beep">
<layers number="3">
<layer index="0" lenght="3">Vishwa</layer>
<layer index="1" lenght="3">Ratna</layer>
</layers>
</network>
Java code:
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;
public class Main {
public static void main(String[] args) {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
try {
DocumentBuilder builder = factory.newDocumentBuilder();
InputStream inputStream = Main.class
.getClassLoader().getResourceAsStream("resources/nodes.xml");
Document doc = builder.parse(inputStream);
NodeList nodes = doc.getElementsByTagName("network");
System.out.println(nodes.item(0).getTextContent());
} catch (FileNotFoundException | ParserConfigurationException e) {
e.printStackTrace();
} catch (SAXException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
O/P
Vishwa
Ratna
This is my XML file:
<Root>
<Id>1</Id>
<Title>My title</Title>
<More>
<Extension>Ex</Extension>
<Extra>Extra info</Extra>
<Comments>
<Comment date="2018-11-26T06:00:00+02:00">Hey, this is my comment</Comment>
<Comment date="2017-11-26T06:00:00+02:00">Hey, this is my comment</Comment>
<Comment date="2016-11-26T06:00:00+02:00">Hey, this is my comment</Comment>
<Comment date="2011-11-26T06:00:00+02:00">Hey, this is my comment</Comment>
</Comments>
</More>
</Root>
I am only interested in <Comment> data.
My current approach is using JaxB unmarshalling and having classes Root.java, More.java, Comments.java which contains class Comment.java. So it's kinda messy.
I have no problem doing it this way, but I would like to know if there is any method that let's you go straight for the <Comment> data and having only 1 class Comment.java for it?
If you only want to get all the comment tags from the XML file, you may try out following approach,
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.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;
public class ReadComments {
public static void main(String[] args) throws ParserConfigurationException, SAXException, IOException {
File xml = new File("D:/data.xml");
DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder docBuilder = dbFactory.newDocumentBuilder();
Document doc = docBuilder.parse(xml);
doc.getDocumentElement().normalize();
NodeList nodeList = doc.getElementsByTagName("Comment");
for (int i= 0; i< nodeList.getLength(); i++) {
Node node = nodeList.item(i);
if (node.getNodeType() == Node.ELEMENT_NODE) {
Element element = (Element) node;
System.out.printf("Comment : %s | Date : %s\n", node.getTextContent(), element.getAttribute("date"));
}
}
}
}
Output :
Comment : Hey, this is my comment | Date : 2018-11-26T06:00:00+02:00
Comment : Hey, this is my comment | Date : 2017-11-26T06:00:00+02:00
Comment : Hey, this is my comment | Date : 2016-11-26T06:00:00+02:00
Comment : Hey, this is my comment | Date : 2011-11-26T06:00:00+02:00
Note that this is just an example to explain about getting details of specific tags, you will have to modify this code as per for your need.
I have this sample xml.
Each row has an id field, it has values as bits.
And I want to find in this file with bitwise-and operator but I don't know if this is possible.
I read about the operator '&' in javascript or comand BITAND in Oracle but nothing in xml o xpath.
This is the example code in java and xpath:
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
public class Util implements java.io.Serializable {
static public String filter_xpath_bitand (int var_tipo)
NodeList nodeList = null;
Element element = null;
try {
XPath xpath = XPathFactory.newInstance().newXPath();
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.parse(new File(fileXML));
nodeList = (NodeList)xpath.evaluate("/test/row[(id & \""+ var_tipo +"\") > 1]", document.getDocumentElement(), XPathConstants.NODESET);
} catch (Exception e) {
System.out.println("*** filterXML --> exception: " + e.toString());
}
}
}
From looking at the XPATH reference there is no such thing as bitwise operations.
You could work around that though by making use of existing operations (mod etc).
See here for a related question.
EDIT:
Sample xml:
<?xml version="1.0" encoding="UTF-8"?>
<test>
<row>
<id>32</id>
<titulo>yellow</titulo>
</row>
<row>
<id>16</id>
<titulo>green</titulo>
</row>
<row>
<id>8</id>
<titulo>red</titulo>
</row>
<row>
<id>1</id>
<titulo>blue</titulo>
</row>
<row>
<id>2</id>
<titulo>white</titulo>
</row>
<row>
<id>4</id>
<titulo>black</titulo>
</row>
</test>
Java code:
import java.io.File;
import java.util.HashSet;
import java.util.Set;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
public class BitWiseXPathTest {
public static void main(String[] args) {
Set<String> selectedColors = new HashSet<String>();
int var_tipo = 33;
try {
XPath xpath = XPathFactory.newInstance().newXPath();
DocumentBuilderFactory factory = DocumentBuilderFactory
.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
String fileXML = "bitwise.xml";
Document document = builder.parse(new File(fileXML));
String evalStr = "/test/row/id";
NodeList nodeList = (NodeList)xpath.evaluate(evalStr, document.getDocumentElement(), XPathConstants.NODESET);
for (int i = 0; i < nodeList.getLength(); i++) {
Node aNode = nodeList.item(i);
if( (Integer.parseInt(aNode.getTextContent()) & var_tipo) > 0) {
//System.out.println("color: "+aNode.getNextSibling().getNextSibling().getTextContent());
selectedColors.add(aNode.getNextSibling().getNextSibling().getTextContent());
}
}
} catch (Exception e) {
System.out.println("*** filterXML --> exception: " + e.toString());
}
System.out.println(selectedColors);
}
}
Again, XPATH doesn't seem to have a bitwise operation. You could move the operation outside of XPATH and do it in Java as a workaround.
Edit: here's how I'm loading the XML document, as I used it in Blaise's answer. I'm loading it like this because I want to work with a node, not the whole doc. Even using the whole document I'm still having trouble when loading in this manner.
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setValidating(false);
factory.setNamespaceAware(false);
DocumentBuilder builder = factory.newDocumentBuilder();
Document doc = builder.parse("[path to doc]/input.xml");
TestClass testClass = (TestClass) unmarshaller.unmarshal(doc);
I've got XML that looks like this:
<test>
<items>
<item type="cookie">cookie</item>
<item type="crackers">crackers</item>
</items>
</test>
And a class:
#XmlAccessorType(XmlAccessType.FIELD)
#XmlRootElement(name = "test")
public class TestClass
{
#XmlPath("items/item/text()")
#XmlElement
private ArrayList<String> itemList = new ArrayList<String>();
// getters, setters omitted
}
The above code will work whether or not I have #XmlElement, and I get an ArrayList containing [cookie, crackers].
If I change the declaration above to
#XmlPath("items/item/#type")
#XmlElement
private ArrayList<String> itemList = new ArrayList<String>();
my ArrayList is empty.
My ultimate goal is to just have attributes so my XML would look like this:
<test>
<items>
<item type="cookie"/>
<item type="crackers"/>
</items>
</test>
Is what I'm trying to do, pull out a list of attributes using XPath, possible, and if so, how?
Thank you.
UPDATE
I have been able to confirm the issue you are seeing (https://bugs.eclipse.org/353763). A fix has been added into our EclipseLink 2.3.1 and 2.4.0 streams and can be obtained from the nightly download page starting August 4th, 2011:
http://www.eclipse.org/eclipselink/downloads/nightly.php
Workaround:
You can workaround this issue by setting your DocumentBuilderFactory to be namespace aware:
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setNamespaceAware(true);
DocumentBuilder builder = factory.newDocumentBuilder();
Document doc = builder.parse("src/forum6907225/input.xml");
testClass = (TestClass) unmarshaller.unmarshal(doc);
marshaller.marshal(testClass, System.out);
You are doing the mapping correctly (see below). Have you included a jaxb.properties file to specify EclipseLink MOXy as your JAXB provider?:
http://blog.bdoughan.com/2011/05/specifying-eclipselink-moxy-as-your.html
Test Class
package forum6907225;
import java.util.ArrayList;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
import org.eclipse.persistence.oxm.annotations.XmlPath;
#XmlAccessorType(XmlAccessType.FIELD)
#XmlRootElement(name = "test")
public class TestClass
{
#XmlPath("items/item/#type")
#XmlElement
private ArrayList<String> itemList = new ArrayList<String>();
// getters, setters omitted
}
Demo
package forum6907225;
import java.io.File;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;
import org.eclipse.persistence.Version;
public class Demo {
public static void main(String[] args) throws Exception {
JAXBContext jc = JAXBContext.newInstance(TestClass.class);
System.out.println(Version.getVersionString());
Unmarshaller unmarshaller = jc.createUnmarshaller();
File xml = new File("src/forum6907225/input.xml");
TestClass testClass = (TestClass) unmarshaller.unmarshal(xml);
Marshaller marshaller = jc.createMarshaller();
marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
marshaller.marshal(testClass, System.out);
}
}
input.xml
<?xml version="1.0" encoding="UTF-8"?>
<test>
<items>
<item type="cookie">cookie</item>
<item type="crackers">crackers</item>
</items>
</test>
Output
2.3.1.qualifier
<?xml version="1.0" encoding="UTF-8"?>
<test>
<items>
<item type="cookie"/>
<item type="crackers"/>
</items>
</test>
I found the following easy solution to extracting values from XML file.
import java.io.IOException;
import org.w3c.dom.*;
import org.xml.sax.SAXException;
import javax.xml.parsers.*;
import javax.xml.xpath.*;
public class XPathExample {
public static void main(String[] args)
throws ParserConfigurationException, SAXException,
IOException, XPathExpressionException {
DocumentBuilderFactory domFactory = DocumentBuilderFactory.newInstance();
domFactory.setNamespaceAware(true); // never forget this!
DocumentBuilder builder = domFactory.newDocumentBuilder();
Document doc = builder.parse("c:/temp/books.xml");
XPathFactory factory = XPathFactory.newInstance();
XPath xpath = factory.newXPath();
XPathExpression expr
= xpath.compile("//book[author='Neal Stephenson']/title/text()");
Object result = expr.evaluate(doc, XPathConstants.NODESET);
NodeList nodes = (NodeList) result;
for (int i = 0; i < nodes.getLength(); i++) {
System.out.println(nodes.item(i).getNodeValue());
}
}
}
This uses xpath to extract all books title where the author is Neal Stephenson from the following xml
<inventory>
<book year="2000">
<title>Snow Crash</title>
<author>Neal Stephenson</author>
<publisher>Spectra</publisher>
<isbn>0553380958</isbn>
<price>14.95</price>
</book>
<book year="2005">
<title>Burning Tower</title>
<author>Larry Niven</author>
<author>Jerry Pournelle</author>
<publisher>Pocket</publisher>
<isbn>0743416910</isbn>
<price>5.99</price>
</book>
<book year="1995">
<title>Zodiac</title>
<author>Neal Stephenson</author>
<publisher>Spectra</publisher>
<isbn>0553573862</isbn>
<price>7.50</price>
</book>
<!-- more books... -->
</inventory>
Now this works fine on JDK5 but i am using jdk 1.4
Can this be converted to the java 1.4 equivalent?
All i am trying to do is extract a value from an xml element. For example, in the above xml, i just want something that is the equivalent of getElementByTag("title").
Thanks
Quick google resulted in links like this and this which confirm that JAXP can be downloaded separately and run on top of JDK 1.4.2. You might run into configuration problems as mentioned in the apache link. Good luck!