Question

I’m using a java.util.Date in spring(3.1) data REST. How can I get the date to print in a human readable form? (e.g. MM/DD/YYYY)?

@Entity
public class MyEntity{
...

@Column(name="A_DATE_COLUMN")
@DateTimeFormat(iso=ISO.DATE)
private Date aDate;

..getters and setters

}

However when i print my entity(after overriding toString), I’m always getting the date as a long. It seems like @DateTimeFormat does not change the behaviour. I also tried different iso formats and that didnt help either.

"aDate" : 1320130800000

Here is my POM file entry for the spring data rest

<dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-rest-webmvc</artifactId>
            <version>1.0.0.RELEASE</version>
            <exclusions>
                <exclusion>
                    <groupId></groupId>
                    <artifactId>slf4j-log4j12</artifactId>
                </exclusion>
                <exclusion>
                    <artifactId>commons-logging</artifactId>
                    <groupId>commons-logging</groupId>
                </exclusion>
            </exclusions>
        </dependency>

                <dependency>
            <groupId>joda-time</groupId>
            <artifactId>joda-time</artifactId>
            <version>2.1</version>
        </dependency>

Any help is much appeciated.
PS. Here is the toString Implementation

@Override
    public String toString() {
        return getClass().getName() + "{"+
                 "\n\taDate: " + aDate
                                       + "\n}";
    }

Answer 1

looks like you will need to write a custom serializer to make Jackson (the JSON library spring uses under the hood) properly serialize the date out to text.

your getter will then look like this (where JsonDateSerializer is the custom class)

@JsonSerialize(using=JsonDateSerializer.class) 
public Date getDate() {     
   return date; 
} 

check out this blog post that includes code for the serializer. The serializer code is replicated here, but the explanation in the blog post may help.

/**
 * Used to serialize Java.util.Date, which is not a common JSON
 * type, so we have to create a custom serialize method;.
 */
@Component
public class JsonDateSerializer extends JsonSerializer<Date>{

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

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

        String formattedDate = dateFormat.format(date);

        gen.writeString(formattedDate);
    }
}