How do you specify the date format used when JAXB marshals xsd:dateTime?

Question

When JAXB marshals a date object (XMLGregorianCalendar) into an xsd:dateTime element. How can you specify the format of the resulting XML?

For example: The default data format uses milliseconds <StartDate>2012-08-21T13:21:58.000Z</StartDate> I need to omit the milliseconds. <StartDate>2012-08-21T13:21:58Z</StartDate>

How can I specify the output form/date format that I want it to use? I'm using javax.xml.datatype.DatatypeFactory to create the XMLGregorianCalendar object.

XMLGregorianCalendar xmlCal = datatypeFactory.newXMLGregorianCalendar(cal);

Answer 1

You can use an XmlAdapter to customize how a date type is written to XML.

package com.example;

import java.text.SimpleDateFormat;
import java.util.Date;

import javax.xml.bind.annotation.adapters.XmlAdapter;

public class DateAdapter extends XmlAdapter<String, Date> {

    private final SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

    @Override
    public String marshal(Date v) throws Exception {
        synchronized (dateFormat) {
            return dateFormat.format(v);
        }
    }

    @Override
    public Date unmarshal(String v) throws Exception {
        synchronized (dateFormat) {
            return dateFormat.parse(v);
        }
    }

}

Then you use the @XmlJavaTypeAdapter annotation to specify that the XmlAdapter should be used for a specific field/property.

@XmlElement(name = "timestamp", required = true) 
@XmlJavaTypeAdapter(DateAdapter.class)
protected Date timestamp; 

Using a xjb binding file:

<xjc:javaType name="java.util.Date" xmlType="xs:dateTime"
        adapter="com.example.DateAdapter"/>

will produce the above mentioned annotation.
(By eventually adding the xjc namespace: xmlns:xjc="http://java.sun.com/xml/ns/jaxb/xjc")