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javax.xml.bind.JAXB.unmarshal() Method
Description
The Javax.xml.bind.JAXB.unmarshal(Reader xml, Class <T> type) method reads in a Java object tree from the given XML input.
Declaration
Following is the declaration for javax.xml.bind.JAXB.unmarshal(Reader xml, Class<T> type) method
public static <T> T unmarshal(Reader xml, Class<T> type)
Parameters
xml − The character stream is read as an XML infoset. The encoding declaration in the XML will be ignored. Upon a successful completion, the stream will be closed by this method.
type − A class type to be unmarshaled.
Return Value
The method retutns object of type Class<T>
Exception
NA
Example
The following example shows the usage of javax.xml.bind.JAXB.unmarshal(Reader xml, Class<T> type) method. To proceed, consider the following Student class which will be used to have objects for unmarshalling purpose −
package com.tutorialspoint; import javax.xml.bind.annotation.XmlAttribute; import javax.xml.bind.annotation.XmlElement; import javax.xml.bind.annotation.XmlRootElement; @XmlRootElement public class Student{ 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; } }
Now let us create main class which will be used to marshal ie. convert Student object into an XML file. This example unmarshals the Student.xml file to object and prints.
package com.tutorialspoint; import java.io.File; import java.io.FileReader; import java.io.IOException; import javax.xml.bind.JAXB; public class JAXBDemo { public static void main(String[] args) throws IOException { File f = null; FileReader fr = null; try { // create file writer object f = new File("Student.xml"); // create new file reader fr = new FileReader(f); // marshal object to file input stream Student st = JAXB.unmarshal(fr, Student.class); // prints System.out.println("Age : "+st.getAge()); System.out.println("Name : "+st.getName()); }catch(Exception ex) { ex.printStackTrace(); }finally{ // releases associated resources if(fr!=null) fr.close(); } } }
To create document, an XML file is needed as input. The XML file is named as Student.xml−
<?xml version = "1.0" encoding = "UTF-8" standalone = "no"?> <student id = "10"> <age>14</age> <name>Soniya</name> </student>
Before we proceed for compilation, we need to make sure that that we download JAXB2.xxx.jar and put it in our CLASSPATH. Once setup is ready, let us compile and run the above program, this will produce the following result −
Age : 14 Name : Soniya