Loiane Groner, Brazilian, works as a Java/ Sencha evangelist. She has 7+ years of experience in web development. She is the ESJUG (Espirito Santo Java Users Group) and CampinasJUG (Campinas Java Users Group) leader and coordinator. Loiane is passionate about technology and programming. Also author of ExtJS 4 First Look book. Loiane is a DZone MVB and is not an employee of DZone and has posted 42 posts at DZone. You can read more from them at their website. View Full User Profile

How to Serialize Java.util.Date with Jackson JSON Processor / Spring 3.0

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Quick tip: how to serialize a java.util.Date object with Jackson JSON Processor – Spring MVC 3.

package com.loiane.model;

import java.util.Date;

import org.codehaus.jackson.annotate.JsonAutoDetect;

public class Company {

	private int id;
	private double price;
	private String company;
	private Date date;
	private String size;
	private byte visible;

And I have the following method in my controller:

public @ResponseBody Map<String,List<Company>> view() throws Exception

Which returns a list of Company.

The @ResponseBody annotation instructs Spring MVC to serialize the hashmap to the client. Spring MVC automatically serializes to JSON because the client accepts that content type:

{"total":27,"data":[{"price":71.72,"company":"3m Co","visible":1,"id":1,"size":"large","date":1188615600000},{"price":29.01,"company":"Aloca
Inc","visible":0,"id":2,"size":"medium","date":1185937200000},{"price":83.81,"company":"Altria Group
Inc","visible":0,"id":3,"size":"large","date":1186110000000},{"price":52.55,"company":"American Express Company","visible":1,"id":4,"size":"extra
large","date":1199412000000},{"price":64.13,"company":"American International Group
Inc.","visible":1,"id":5,"size":"small","date":1204599600000},{"price":31.61,"company":"AT&T Inc.","visible":0,"id":6,"size":"extra
large","date":1201831200000},{"price":75.43,"company":"Boeing Co.","visible":1,"id":7,"size":"large","date":1199152800000},{"price":67.27,"company":"Caterpillar
Inc.","visible":1,"id":9,"size":"large","date":1195869600000},{"price":40.48,"company":"E.I. du Pont de Nemours and Company","visible":0,"id":10,"size":"extra

Take a look how the date attibute is being serialized: “date”:1188615600000. Jackson uses default strategy to determine date formatting in serialization.

One of the annotations Jackson has is @JsonSerialize. You basically use this annotation for configuring serialization aspects. In my case, I decorated by model objects date getter method with this annotation:

public Date getDate() {
	return date;

JsonDateSerializer is a class I wrote that extends JsonSerializer that will handle the serialization for this field:


package com.loiane.util;

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

import org.codehaus.jackson.JsonGenerator;
import org.codehaus.jackson.JsonProcessingException;
import org.codehaus.jackson.map.JsonSerializer;
import org.codehaus.jackson.map.SerializerProvider;
import org.springframework.stereotype.Component;

 * Used to serialize Java.util.Date, which is not a common JSON
 * type, so we have to create a custom serialize method;.
 * @author Loiane Groner
 * http://loianegroner.com (English)
 * http://loiane.com (Portuguese)
public class JsonDateSerializer extends JsonSerializer<Date>{

	private static final SimpleDateFormat dateFormat = new SimpleDateFormat("MM-dd-yyyy");

	public void serialize(Date date, JsonGenerator gen, SerializerProvider provider)
			throws IOException, JsonProcessingException {

		String formattedDate = dateFormat.format(date);



And this is how my object is being serialized now:

{"total":27,"data":[{"price":71.72,"company":"3m Co","visible":1,"id":1,"size":"large","date":"09-01-2007"},{"price":29.01,"company":"Aloca
Inc","visible":0,"id":2,"size":"medium","date":"08-01-2007"},{"price":83.81,"company":"Altria Group
Inc","visible":0,"id":3,"size":"large","date":"08-03-2007"},{"price":52.55,"company":"American Express Company","visible":1,"id":4,"size":"extra
large","date":"01-04-2008"},{"price":64.13,"company":"American International Group
Inc.","visible":1,"id":5,"size":"small","date":"03-04-2008"},{"price":31.61,"company":"AT&T Inc.","visible":0,"id":6,"size":"extra
large","date":"02-01-2008"},{"price":75.43,"company":"Boeing Co.","visible":1,"id":7,"size":"large","date":"01-01-2008"},{"price":67.27,"company":"Caterpillar
Inc.","visible":1,"id":9,"size":"large","date":"11-24-2007"},{"price":40.48,"company":"E.I. du Pont de Nemours and Company","visible":0,"id":10,"size":"extra

Happy coding!

From http://loianegroner.com/2010/09/how-to-serialize-java-util-date-with-jackson-json-processor-spring-3-0/

Published at DZone with permission of Loiane Groner, author and DZone MVB.

(Note: Opinions expressed in this article and its replies are the opinions of their respective authors and not those of DZone, Inc.)



Xavier Dury replied on Mon, 2010/09/20 - 3:13am

Using a static date format without synchronization is not recommended.
Excerpt from SimpleDateFormat javadoc:

Date formats are not synchronized. It is recommended to create separate format instances for each thread. If multiple threads access a format concurrently, it must be synchronized externally.

Aries McRae replied on Mon, 2010/09/20 - 6:09am

The Apache FastDateFormat is a thread-safe version of SimpleDateFormat.
It doesn't parse, but it can be used for formatting.

John Cook replied on Mon, 2010/09/20 - 10:12am

I recently decided to ditch using SimpleDateFormat altogether because thinking about thread safety when you don't have to sucks.  As mentioned, use FastDateFormat.  Or use the Joda Time API.

Here's a shameless link to my blog about date formatting:


Javin Paul replied on Sat, 2011/04/16 - 9:22am

Nice article , you have indeed covered topic in details and code example.

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