Java - Reading XML file
Solution 1:
One of the possible implementations:
File file = new File("userdata.xml");
DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory
.newInstance();
DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
Document document = documentBuilder.parse(file);
String usr = document.getElementsByTagName("user").item(0).getTextContent();
String pwd = document.getElementsByTagName("password").item(0).getTextContent();
when used with the XML content:
<credentials>
<user>testusr</user>
<password>testpwd</password>
</credentials>
results in "testusr" and "testpwd" getting assigned to the usr and pwd references above.
Solution 2:
Reading xml the easy way:
http://www.mkyong.com/java/jaxb-hello-world-example/
package com.mkyong.core;
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
@XmlRootElement
public class Customer {
String name;
int age;
int id;
public String getName() {
return name;
}
@XmlElement
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
@XmlElement
public void setAge(int age) {
this.age = age;
}
public int getId() {
return id;
}
@XmlAttribute
public void setId(int id) {
this.id = id;
}
}
.
package com.mkyong.core;
import java.io.File;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
public class JAXBExample {
public static void main(String[] args) {
Customer customer = new Customer();
customer.setId(100);
customer.setName("mkyong");
customer.setAge(29);
try {
File file = new File("C:\\file.xml");
JAXBContext jaxbContext = JAXBContext.newInstance(Customer.class);
Marshaller jaxbMarshaller = jaxbContext.createMarshaller();
// output pretty printed
jaxbMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
jaxbMarshaller.marshal(customer, file);
jaxbMarshaller.marshal(customer, System.out);
} catch (JAXBException e) {
e.printStackTrace();
}
}
}
Solution 3:
If using another library is an option, the following may be easier:
package for_so;
import java.io.File;
import rasmus_torkel.xml_basic.read.TagNode;
import rasmus_torkel.xml_basic.read.XmlReadOptions;
import rasmus_torkel.xml_basic.read.impl.XmlReader;
public class Q7704827_SimpleRead
{
public static void
main(String[] args)
{
String fileName = args[0];
TagNode emailNode = XmlReader.xmlFileToRoot(new File(fileName), "EmailSettings", XmlReadOptions.DEFAULT);
String recipient = emailNode.nextTextFieldE("recipient");
String sender = emailNode.nextTextFieldE("sender");
String subject = emailNode.nextTextFieldE("subject");
String description = emailNode.nextTextFieldE("description");
emailNode.verifyNoMoreChildren();
System.out.println("recipient = " + recipient);
System.out.println("sender = " + sender);
System.out.println("subject = " + subject);
System.out.println("desciption = " + description);
}
}
The library and its documentation are at rasmustorkel.com
Solution 4:
Avoid hardcoding try making the code that is dynamic below is the code it will work for any xml I have used SAX Parser you can use dom,xpath it's upto you
I am storing all the tags name and values in the map after that it becomes easy to retrieve any values you want I hope this helps
SAMPLE XML:
<parent>
<child >
<child1> value 1 </child1>
<child2> value 2 </child2>
<child3> value 3 </child3>
</child>
<child >
<child4> value 4 </child4>
<child5> value 5</child5>
<child6> value 6 </child6>
</child>
</parent>
JAVA CODE:
import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
public class saxParser {
static Map<String,String> tmpAtrb=null;
static Map<String,String> xmlVal= new LinkedHashMap<String, String>();
public static void main(String[] args) throws ParserConfigurationException, SAXException, IOException, VerifyError {
/**
* We can pass the class name of the XML parser
* to the SAXParserFactory.newInstance().
*/
//SAXParserFactory saxDoc = SAXParserFactory.newInstance("com.sun.org.apache.xerces.internal.jaxp.SAXParserFactoryImpl", null);
SAXParserFactory saxDoc = SAXParserFactory.newInstance();
SAXParser saxParser = saxDoc.newSAXParser();
DefaultHandler handler = new DefaultHandler() {
String tmpElementName = null;
String tmpElementValue = null;
@Override
public void startElement(String uri, String localName, String qName,
Attributes attributes) throws SAXException {
tmpElementValue = "";
tmpElementName = qName;
tmpAtrb=new HashMap();
//System.out.println("Start Element :" + qName);
/**
* Store attributes in HashMap
*/
for (int i=0; i<attributes.getLength(); i++) {
String aname = attributes.getLocalName(i);
String value = attributes.getValue(i);
tmpAtrb.put(aname, value);
}
}
@Override
public void endElement(String uri, String localName, String qName)
throws SAXException {
if(tmpElementName.equals(qName)){
System.out.println("Element Name :"+tmpElementName);
/**
* Retrive attributes from HashMap
*/ for (Map.Entry<String, String> entrySet : tmpAtrb.entrySet()) {
System.out.println("Attribute Name :"+ entrySet.getKey() + "Attribute Value :"+ entrySet.getValue());
}
System.out.println("Element Value :"+tmpElementValue);
xmlVal.put(tmpElementName, tmpElementValue);
System.out.println(xmlVal);
//Fetching The Values From The Map
String getKeyValues=xmlVal.get(tmpElementName);
System.out.println("XmlTag:"+tmpElementName+":::::"+"ValueFetchedFromTheMap:"+getKeyValues);
}
}
@Override
public void characters(char ch[], int start, int length) throws SAXException {
tmpElementValue = new String(ch, start, length) ;
}
};
/**
* Below two line used if we use SAX 2.0
* Then last line not needed.
*/
//saxParser.setContentHandler(handler);
//saxParser.parse(new InputSource("c:/file.xml"));
saxParser.parse(new File("D:/Test _ XML/file.xml"), handler);
}
}
OUTPUT:
Element Name :child1
Element Value : value 1
XmlTag:<child1>:::::ValueFetchedFromTheMap: value 1
Element Name :child2
Element Value : value 2
XmlTag:<child2>:::::ValueFetchedFromTheMap: value 2
Element Name :child3
Element Value : value 3
XmlTag:<child3>:::::ValueFetchedFromTheMap: value 3
Element Name :child4
Element Value : value 4
XmlTag:<child4>:::::ValueFetchedFromTheMap: value 4
Element Name :child5
Element Value : value 5
XmlTag:<child5>:::::ValueFetchedFromTheMap: value 5
Element Name :child6
Element Value : value 6
XmlTag:<child6>:::::ValueFetchedFromTheMap: value 6
Values Inside The Map:{child1= value 1 , child2= value 2 , child3= value 3 , child4= value 4 , child5= value 5, child6= value 6 }