Spring: create LocalDate or LocalDateTime from @Value parameter

Question

In a spring project, I'd like to create a LocalDate from an @Autowired constructor parameter whose value is in a .properties file. Two things I'd like to do:

1. If the property file contains the property my.date, the parameter should be created by parsing the property value

When the property is set, and when I use the following:

@DateTimeFormat(pattern = "yyyy-MM-dd") @Value("${my.date}") LocalDate myDate,
...

I get this error: java.lang.IllegalStateException: Cannot convert value of type 'java.lang.String' to required type 'java.time.LocalDate': no matching editors or conversion strategy found

I have also used the iso = ... to use an ISO date with the same result.

2. If the property is not in the properties file, the parameter should be created using LocalDate.now()

I tried using a default value as such:

@Value("${my.date:#{T(java.time.LocalDate).now()}}") LocalDate myDate,
...

But I get the same error.

Forgive my ignorance with Spring, but how can I achieve the two objectives here?

Answer 1

I know two ways. One is generic for any object - to use @Value annotation on custom setter

@Component
public class Example {

    private LocalDate localDate;

    @Value("${property.name}")
    private void setLocalDate(String localDateStr) {
        if (localDateStr != null && !localDateStr.isEmpty()) {
            localDate = LocalDate.parse(localDateStr);
        }
    }
}

The second is for LocalDate/LocalDateTime

public class Example {
    @Value("#{T(java.time.LocalDate).parse('${property.name}')}")
    private LocalDate localDate;
}

Sample property:

property.name=2018-06-20

Answer 2

Spring Boot 2.5, works perfect:

application.yaml

my.date: 2021-08-14
my.time: "11:00"

@Service
public class TestService {
    @Value("${my.date}")
    @DateTimeFormat(pattern = "yyyy-MM-dd")
    LocalDate myDate;

    @Value("${my.time}")
    @DateTimeFormat(iso = DateTimeFormat.ISO.TIME)
    LocalTime myTime;
}