Date format in the json output using spring boot

Question

I am working on spring boot for creating a REST application. And I have a DTO as shown below:

public class Subject {

private String uid;
private String number;
private String initials;
private Date dateOfBirth;

And I use Spring-Hateos and the reurn type of my controller is ResponseEntity<Resources<Resource<Subject>>>. I need the date to be displayed in the "yyyy-mm-dd" format.

Answer 1

Starting from Spring Boot version 1.2.0.RELEASE , there is a property you can add to your application.properties to set a default date format to all of your classes spring.jackson.date-format.

For your date format example, you would add this line to your properties file:

spring.jackson.date-format=yyyy-MM-dd

Reference https://docs.spring.io/spring-boot/docs/1.2.0.RELEASE/reference/html/common-application-properties.html

Answer 2

If you have Jackson integeration with your application to serialize your bean to JSON format, then you can use Jackson anotation @JsonFormat to format your date to specified format.
In your case if you need your date into yyyy-MM-dd format you need to specify @JsonFormat above your field on which you want to apply this format.

For Example :

public class Subject {

     private String uid;
     private String number;
     private String initials;

     @JsonFormat(pattern="yyyy-MM-dd")
     private Date dateOfBirth;  

     //Other Code  

}  

From Docs :

annotation used for configuring details of how values of properties are to be serialized.

More Reference Doc

Hope this helps.

Answer 3

If you want to change the format for all dates you can add a builder customizer. Here is an example of a bean that converts dates to ISO 8601:

@Bean
public Jackson2ObjectMapperBuilderCustomizer jsonCustomizer() {
    return new Jackson2ObjectMapperBuilderCustomizer() {
        @Override
        public void customize(Jackson2ObjectMapperBuilder builder) {
            builder.dateFormat(new ISO8601DateFormat());        
        }           
    };
}

Answer 4

You most likely mean "yyyy-MM-dd" small latter 'm' would imply minutes section.

You should do two things

• add spring.jackson.serialization.write-dates-as-timestamps:false in your application.properties this will disable converting dates to timestamps and instead use a ISO-8601 compliant format

• You can than customize the format by annotating the getter method of you dateOfBirth property with @JsonFormat(pattern="yyyy-MM-dd")