Java 8 LocalDate Jackson format

Question

For java.util.Date when I do

@JsonFormat(shape = JsonFormat.Shape.STRING, pattern = \"dd/MM/yyyy\")  
  private Date dateOfBirth;
<         


        

Answer 1

https://stackoverflow.com/a/53251526/1282532 is the simplest way to serialize/deserialize property. I have two concerns regarding this approach - up to some point violation of DRY principle and high coupling between pojo and mapper.

public class Trade {
    @JsonFormat(pattern = "yyyyMMdd")
    @JsonDeserialize(using = LocalDateDeserializer.class)
    @JsonSerialize(using = LocalDateSerializer.class)
    private LocalDate tradeDate;
    @JsonFormat(pattern = "yyyyMMdd")
    @JsonDeserialize(using = LocalDateDeserializer.class)
    @JsonSerialize(using = LocalDateSerializer.class)
    private LocalDate maturityDate;
    @JsonFormat(pattern = "yyyyMMdd")
    @JsonDeserialize(using = LocalDateDeserializer.class)
    @JsonSerialize(using = LocalDateSerializer.class)
    private LocalDate entryDate;
}

In case you have POJO with multiple LocalDate fields it's better to configure mapper instead of POJO. It can be as simple as https://stackoverflow.com/a/35062824/1282532 if you are using ISO-8601 values ("2019-01-31")

In case you need to handle custom format the code will be like this:

ObjectMapper mapper = new ObjectMapper();
JavaTimeModule javaTimeModule = new JavaTimeModule();
javaTimeModule.addDeserializer(LocalDate.class, new LocalDateDeserializer(DateTimeFormatter.ofPattern("yyyyMMdd")));
javaTimeModule.addSerializer(LocalDate.class, new LocalDateSerializer(DateTimeFormatter.ofPattern("yyyyMMdd")));
mapper.registerModule(javaTimeModule);

The logic is written just once, it can be reused for multiple POJO