JAXB Date Format Example using Annotation | Java Date to XML DateTime String Conversion
One of the common problem while marshaling Java object to XML String using JAXB is the default format of date and time provided by JAXB. When JAXB converts any Date type object or XMLGregorianCalendar to XML String, precisely xsd:dateTime element, it by default prints unformatted date e.g. 2012-05-17T09:20:00-04:30 . Since most of the real world, Java application has a requirement to print date in a particular format like dd-MM-yyyy or include date and time in format dd-MM-yyyy HH:mm:ss , it becomes a problem . Thankfully, JAXB is very extensible and provides hooks and adapters to customize marshaling and unmarshaling process. You can define an extension of XmlAdapter to control and customize marshaling and unmarshaling or any Java type depending upon yours need.
In this JAXB tutorial, we will see an example of customizing JAXB to format date and time in an application specific format.
For our purpose, we will use the SimpleDateFormat class, which has its own issues, but that’s ok for demonstration purpose. To get a clarity of what is the issue with the date format, and what we are doing in this example, consider following xml snippet, which is created from our Employee object, without formatting Date, XML will look like:
John 1985-01-15T18:30:00-04:00 2012-05-17T09:20:00-04:30
While after using XmlAdapter for controlling marshaling of date object in JAXB, our XML String snippet will look like below:
XML String after formatting date in dd-MM-yyyy HH:mm:ss format
John 15-01-1985 18:30:00 17-05-2012 09:20:00
You can see that, in the second XML, dates are properly formatted including both date and time information. You can even further customize it into several other date formats e.g. MM/dd/yyyy , you just need to remember SimpleDateFormat sy ntax for formatting dates, as shown here.
JAXB Date Format Example
Here is the complete code example of formatting dates in JAXB. It allows you to specify Adapters, which can be used for marshaling and unmarshaling different types of object, for example, you can specify DateTimeAdapter for converting Date to String during marshaling, and XML String to Date during unmarshaling.
Apart from writing your own Adapter, which should extend the XmlAdapter class, you also need to use annotation @XmlJavaTypeAdapter to specify that JAXB should use that adapter for marshaling and unmarshalling of a particular object.
In this JAXB tutorial, we have written our own DateTimeAdapter , which extends XmlAdapter and overrides marshal(Date object) and unmarshal(String xml) methods. JAXB calls marshal method, while converting Java Object to XML document, and unmarshal method to bind XML document to Java object.
We are also using SimpleDateFormat class, to format Date object into dd-MM-yyyy HH:mm:ss format, which print date as 15-01-1985 18:30:00. By the way, be careful while using SimpleDateFormat , as it’s not thread-safe.
Java Program to convert Java Object to XML with formatted Dates
import java.io.StringWriter; import java.text.DateFormat; import java.text.SimpleDateFormat; import java.util.Calendar; import java.util.Date; import java.util.GregorianCalendar; import javax.xml.bind.JAXBContext; import javax.xml.bind.JAXBException; import javax.xml.bind.annotation.XmlAccessType; import javax.xml.bind.annotation.XmlAccessorType; import javax.xml.bind.annotation.XmlElement; import javax.xml.bind.annotation.XmlRootElement; import javax.xml.bind.annotation.adapters.XmlAdapter; import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter; /** * * JAXB tutorial to format Date to XML String while converting Java object to * XML documents i.e. during marshalling. * * @author Javin Paul */ public class JAXBDateFormatTutorial < public static void main(String args[]) < Date dob = new GregorianCalendar(1985,Calendar.JANUARY, 15, 18, 30) .getTime(); Date doj = new GregorianCalendar(2012,Calendar.MAY, 17, 9, 20) .getTime(); Employee john = new Employee("John", dob, doj); // Marshaling Employee object to XML using JAXB JAXBContext ctx = null; StringWriter writer = new StringWriter(); try< ctx = JAXBContext.newInstance(Employee.class); ctx.createMarshaller().marshal(john, writer); System.out.println("Employee object as XML"); System.out.println(writer); >catch(JAXBException ex)< ex.printStackTrace(); > > >
When you will run this program it will print the Employee object in XML as shown below:
Employee object as XML "1.0" encoding="UTF-8" standalone="yes"?> employee> name>John dateOfBirth>15-01-1985 18:30:00 dateOfJoining>17-05-2012 09:20:00 /employee>
You can see that dates are nicely formatted and there is no more T in between as it was before.
In this program, there are three main classes: Employee , DateTimeAdapter , and JAXBDateFormatTutorial , each class is coded in their respective file because they are public classes e.g. Employee.java contains Employee class. If you want to include then in the same file, just remove the public modifier from Employee and DateTimeAdapter class.
The Employee class is your domain object while DateTimeAdapter is an extension of XmlAdapter to format dates while converting XML to Java object and vice-versa.
As I said, JAXB is very extensible and provides a lot of hooks where you can insert your own code for customization. If you want to learn more about the advanced usage of JAXB, I suggest you joining these Java Programing and Development courses and books to learn XML parsing in Java.
@XmlRootElement(name="employee") @XmlAccessorType(XmlAccessType.FIELD) public class Employee< @XmlElement(name="name") private String name; @XmlElement(name="dateOfBirth") @XmlJavaTypeAdapter(DateTimeAdapter.class) private Date dateOfBirth; @XmlElement(name="dateOfJoining") @XmlJavaTypeAdapter(DateTimeAdapter.class) private Date dateOfJoining; // no-arg default constructor for JAXB public Employee()<> public Employee(String name, Date dateOfBirth, Date dateOfJoining) < this.name = name; this.dateOfBirth = dateOfBirth; this.dateOfJoining = dateOfJoining; > public Date getDateOfBirth() < return dateOfBirth; > public void setDateOfBirth(Date dateOfBirth) < this.dateOfBirth = dateOfBirth; > public Date getDateOfJoining() < return dateOfJoining; > public void setDateOfJoining(Date dateOfJoining) < this.dateOfJoining = dateOfJoining; > public String getName() < return name; > public void setName(String name) < this.name = name; > @Override public String toString() < return "Employee + "name color: #2060a0;">+ name + ", dateOfBirth color: #2060a0;"> + dateOfBirth + ", dateOfJoining color: #2060a0;">+ dateOfJoining + '>'; > >
public class DateTimeAdapter extends XmlAdapterString, Date>< private final DateFormat dateFormat = new SimpleDateFormat("dd-MM-yyyy HH:mm:ss"); @Override public Date unmarshal(String xml) throws Exception < return dateFormat.parse(xml); > @Override public String marshal(Date object) throws Exception < return dateFormat.format(object); > >
Things to Remember
Here are a couple of important things to remember while
1) Don’t forget to provide a no argument default constructor for your domain object e.g. Employee, failing to do will result in the following error while marshaling Java Object to XML String:
com.sun.xml.internal.bind.v2.runtime.IllegalAnnotationsException: 1 counts of IllegalAnnotationExceptions Employee does not have a no-arg default constructor.
this problem is related to the following location:
at Employee
at com.sun.xml.internal.bind.v2.runtime.IllegalAnnotationsException$Builder.check(IllegalAnnotationsException.java:91)
at com.sun.xml.internal.bind.v2.runtime.JAXBContextImpl.getTypeInfoSet(JAXBContextImpl.java:436)
That’s all on How to format Dates in JAXB. We have not only learned Date formatting during marshaling of the Date object but also seen how to customize JAXB marshaling and unmarshalling process. You can use this technique to customize marshaling of any Java type e.g. BigDecimal , float , or double, etc. Just remember to use annotation @XmlJavaTypeAdapter to specify the name of your custom date and time Adapter to the JAXB marshaller.
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P. S. — If you are interested in learning how to deal with XML in Java in more detail, you can read Java and XML — Solutions of Real World Problem by Brett McLaughlin. It covers everything with respect to parsing XML e.g. SAX, DOM, and StAX parser, JAXB, XPath, XSLT, and JAXB. One of the good books for advanced Java developers.
Annotation date format java
Declares that a field should be formatted as a date time. Supports formatting by style pattern, ISO date time pattern, or custom format pattern string. Can be applied to java.util.Date , java.util.Calendar , java.long.Long , Joda-Time value types; and as of Spring 4 and JDK 8, to JSR-310 java.time types too. For style-based formatting, set the style() attribute to be the style pattern code. The first character of the code is the date style, and the second character is the time style. Specify a character of ‘S’ for short style, ‘M’ for medium, ‘L’ for long, and ‘F’ for full. A date or time may be omitted by specifying the style character ‘-‘. For ISO-based formatting, set the iso() attribute to be the desired DateTimeFormat.ISO format, such as DateTimeFormat.ISO.DATE . For custom formatting, set the pattern() attribute to be the DateTime pattern, such as yyyy/MM/dd hh:mm:ss a . Each attribute is mutually exclusive, so only set one attribute per annotation instance (the one most convenient one for your formatting needs). When the pattern attribute is specified, it takes precedence over both the style and ISO attribute. When the iso() attribute is specified, it takes precedence over the style attribute. When no annotation attributes are specified, the default format applied is style-based with a style code of ‘SS’ (short date, short time).
Optional Element Summary
Element Detail
style
public abstract java.lang.String style
The style pattern to use to format the field. Defaults to ‘SS’ for short date time. Set this attribute when you wish to format your field in accordance with a common style other than the default style.
iso
The ISO pattern to use to format the field. The possible ISO patterns are defined in the DateTimeFormat.ISO enum. Defaults to DateTimeFormat.ISO.NONE , indicating this attribute should be ignored. Set this attribute when you wish to format your field in accordance with an ISO format.
pattern
public abstract java.lang.String pattern
The custom pattern to use to format the field. Defaults to empty String, indicating no custom pattern String has been specified. Set this attribute when you wish to format your field in accordance with a custom date time pattern not represented by a style or ISO format. Note: This pattern follows the original SimpleDateFormat style, as also supported by Joda-Time, with strict parsing semantics towards overflows (e.g. rejecting a Feb 29 value for a non-leap-year). As a consequence, ‘yy’ characters indicate a year in the traditional style, not a «year-of-era» as in the DateTimeFormatter specification (i.e. ‘yy’ turns into ‘uu’ when going through that DateTimeFormatter with strict resolution mode).