Java HTML / XML How to - Detect the Invalid Value in jaxb

Question

We would like to know how to detect the Invalid Value in jaxb.

Answer

Java Model (Foo)

import javax.xml.bind.annotation.XmlRootElement;
/*from   www.  j  a v  a2 s . c om*/
@XmlRootElement
public class Foo {

    private boolean bar;

    public boolean isBar() {
        return bar;
    }

    public void setBar(boolean bar) {
        this.bar = bar;
    }

}

Demo

import java.io.StringReader;
//from ww w. j a v  a  2  s .com
import javax.xml.bind.JAXBContext;
import javax.xml.bind.Unmarshaller;
import javax.xml.bind.ValidationEvent;
import javax.xml.bind.ValidationEventHandler;

public class Main {

  public static void main(String[] args) throws Exception {
    JAXBContext jc = JAXBContext.newInstance(Foo.class);

    Unmarshaller unmarshaller = jc.createUnmarshaller();
    StringReader xml = new StringReader("<foo><bar>toast</bar></foo>");
    Foo foo = (Foo) unmarshaller.unmarshal(xml);
    unmarshaller.setEventHandler(new ValidationEventHandler() {
      @Override
      public boolean handleEvent(ValidationEvent ve) {
        System.out.println(ve.getMessage());
        return true;
      }
    });

    System.out.println(foo.isBar());
  }

}