json date format in spring-boot

Question

I am using spring-boot and I have an entity class defined something like this

import org.joda.time.LocalDateTime;
@Entity
public class Project {

    @Type(type = "org.jadira.usertype.dateandtime.joda.PersistentLocalDateTime")
    private LocalDateTime start_date;
...
...
}

When this class is converted to JSON, the field gets converted to the following string representation

{"start_date":[2014,11,15,0,0,0,0],...., ...}

I want to have the json response as yyyy-MM-dd.

I tried the @DateTimeFormat(iso = ISO.DATE) annotation and that did not help either.

Is there an easy way to do this conversion to proper json format ?

Answer 1

There are three things that you need to do to format the date as yyyy-MM-dd:

1. Add a dependency on com.fasterxml.jackson.datatype:jackson-datatype-joda. Judging by the output you're getting at the moment, I think you may already have this dependency.
2. Configure Jackson not to format dates as timestamps by adding spring.jackson.serialization.write-dates-as-timestamps: false to your application.properties file.
3. Annotate the LocalDataTime field or getter method with @JsonFormat(pattern="yyyy-MM-dd")

Note: You'll need to use Spring Boot 1.2 for step 2 to work.

Answer 2

Without additional dependency - the only thing I had to do is:

1. To take care send date from client as string object, in format yyyy/MM/dd

2. In Spring Boot application, to add annotation on the date field with the same format

---

public class Foo
{
     @JsonFormat(pattern = "yyyy/MM/dd")
     private Date dueDate;
}

Using Spring Boot 2.3.5 version

---

Update

Another option, instead of step 2, to modify application.properties file, add there the format for any Date object:

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

Answer 3

You can use @JsonFormat annotation in and the desired pattern like this without using any dependency :

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