Jackson MappingJacksonHttpMessageConverter/ObjectMapper for Date not working

[iktuz]

Hi All,

When I transport Date as JSON reponse from server to the client page, the format is serialized as timestamp by default, like numeric value. I am trying to customize another format using a Date mask (with SimpleDateFormat). I was digging around a way to customize a global JSON Date response formatter. I dont want to use annotation for all date bean fields. All the suggestions I have followed around internet have failed. The most curious is that no exception is raised.

I am using:

• Spring 3.0.6
• jackson-core-asl-1.4.2 (** I have tried 1.8 and 1.9 as well)
• jackson-mapper-asl-1.4.2 (** I have tried 1.8 and 1.9 as well)

web.xml:

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
	id="WebApp_ID" version="2.5">

	<display-name>My App</display-name>

	<welcome-file-list>
		<welcome-file>index.jsp</welcome-file>
	</welcome-file-list>

	<session-config>
        <session-timeout>5</session-timeout>
    </session-config>

	<context-param>
		<param-name>contextConfigLocation</param-name>
		<param-value>/WEB-INF/myApp-servlet.xml</param-value>
	</context-param>

	<filter>
		<filter-name>springSecurityFilterChain</filter-name>
		<filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
	</filter>

	<filter-mapping>
		<filter-name>springSecurityFilterChain</filter-name>
		<url-pattern>/*</url-pattern>
	</filter-mapping>

	<servlet>
		<servlet-name>myApp</servlet-name>
		<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
		<load-on-startup>1</load-on-startup>
	</servlet>

	<listener>
		<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
	</listener>

	<servlet-mapping>
		<servlet-name>myApp</servlet-name>
		<url-pattern>*.html</url-pattern>
	</servlet-mapping>

</web-app>

Here is myApp-servlet.xml

    <context:annotation-config />

    <aop:aspectj-autoproxy proxy-target-class="true" />

    <context:component-scan base-package="com.app" />

    <mvc:annotation-driven />

    <!-- Configures Handler Interceptors -->   
    <mvc:interceptors>
        <!-- Changes the locale when a 'locale' request parameter is sent; e.g. /?locale=de -->
        <bean class="org.springframework.web.servlet.i18n.LocaleChangeInterceptor" />
    </mvc:interceptors>

    <!-- ... some mvc:view-controller declarations ... -->

    <bean id="defaultViewResolver" class="org.springframework.web.servlet.view.UrlBasedViewResolver">
        <property name="viewClass" value="org.springframework.web.servlet.view.JstlView" />
        <property name="prefix" value="/WEB-INF/pages/" />
        <property name="suffix" value=".jsp" />
    </bean>
...
<!-- For JSON converter support -->
    <bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
        <property name="messageConverters">
            <list>
                <!-- Support JSON --> 
                <bean class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter">
                    <property name="objectMapper" ref="jacksonDateMapper" />
                </bean>
        </property>
    </bean>
    
    <bean id="jacksonDateMapper" class="com.app.mapper.DateMapper">
        <property name="mask" value="dd-MM-yyyy HH:mm" />
    </bean>
...

And finally my DateMapper implementation:

package com.app.mapper;

import java.text.SimpleDateFormat;

import javax.annotation.PostConstruct;

import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.map.SerializationConfig;
import org.springframework.stereotype.Component;

@Component("jacksonDateMapper")
public class DateMapper extends ObjectMapper {

	private String mask = "MM dd yyyy HH mm ss";

	@PostConstruct
	public void afterPropertiesSet() throws Exception {
		super.configure(SerializationConfig.Feature.WRITE_DATES_AS_TIMESTAMPS, false);
                            //Using Jackson > 1.8 it's possible to invoke 'getSerializationConfig().withDateFormat(new SimpleDateFormat(mask));', doesnt work ;(
		getSerializationConfig().setDateFormat(new SimpleDateFormat(mask));
	}
	
	public void setMask(String mask) {
		this.mask = mask;
	}

}

In the end, the date objects are still serialized as numbers, not following my formatter. That's it, can someone point some direction?

Thanks a lot,
Iktuz.

[iktuz]

Reading Scott Fredericks's Blog I realized that I should bind the original Spring's AnnotationMethodHandlerAdapter instance with my customized ObjectMapper. In the first approach I was creating two instances and of course, mine wasn't be used, what explains why nothing happened. So the final configuration must be done as follows:

    <bean id="jacksonDateMapper" class="com.app.web.DateMapper">
        <property name="mask" value="dd-MM-yyyy HH:mm" />
    </bean>

    <bean id="jsonConverter" class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter">
        <property name="objectMapper" ref="jacksonDateMapper" />
    </bean>

    <bean class="com.app.web.ConverterRegister">
        <property name="messageConverters">
            <list>
                <ref bean="jsonConverter" />
            </list>
        </property>
    </bean>

The class com.app.web.ConverterRegister is the binder:

package com.app.web;

import javax.annotation.PostConstruct;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter;

@Component
public class ConverterRegister {
	
	@Autowired
	private AnnotationMethodHandlerAdapter adapter;

	private HttpMessageConverter<?>[] messageConverters;
	
	public void setMessageConverters(HttpMessageConverter<?>[] messageConverters) {
		this.messageConverters = messageConverters;
	}

	@PostConstruct
	public void bindMessageConverters() {
		adapter.setMessageConverters(messageConverters);
	}

}

The class DateMapper does the job, applying the format:

package com.app.web;

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

import javax.annotation.PostConstruct;

import org.codehaus.jackson.JsonGenerator;
import org.codehaus.jackson.JsonProcessingException;
import org.codehaus.jackson.map.JsonSerializer;
import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.map.SerializationConfig;
import org.codehaus.jackson.map.SerializerProvider;
import org.codehaus.jackson.map.ser.CustomSerializerFactory;
import org.springframework.stereotype.Component;

@Component("jacksonDateMapper")
public class DateMapper extends ObjectMapper {

	private String mask = "MM-dd-yyyy HH:mm:ss";

	@PostConstruct
	public void afterPropertiesSet() throws Exception {
		super.configure(SerializationConfig.Feature.WRITE_DATES_AS_TIMESTAMPS, false);

                            //this one doesn't work at all, it's necessary to create and register a factory
		//getSerializationConfig().withDateFormat(new SimpleDateFormat(mask));

                            //I am using Jackson 1.9 asl
		CustomSerializerFactory factory = new CustomSerializerFactory();
		factory.addSpecificMapping(Date.class, new JsonSerializer<Date>() {

			@Override
			public Class<Date> handledType() { return Date.class; }

			@Override
			public void serialize(Date value, JsonGenerator jgen,
					SerializerProvider provider) throws IOException,
					JsonProcessingException {

				jgen.writeString(new SimpleDateFormat(mask).format(value));
			}});
                           this.setSerializerFactory(factory);
	}

	public void setMask(String mask) {
		this.mask = mask;
	}

}

The factory exemple above I saw in another blog, sorry for the guy with the due credits. I apologize not having the URL. Well, in the end all the date instances are converted based on the specified format.

In the future I intend to use the user's locale to switch among many masks, any help will be very appreciated.

Thanks a lot,
Iktuz.