Spring boot 2 Converting Duration java 8 application.properties

Question

I need to define Duration value (spring.redis.timeout) by application.properties.

I was trying to use one point defined in Spri

Answer 1

The Duration in the moment (Spring-Boot 2.0.4.RELEASE) it is not possible to use together with @Value notation, but it is possible to use with @ConfigurationProperties

For Redis, you have RedisProperties and you can use the configuration:

spring.redis.timeout=5s

And:

@SpringBootApplication
public class DemoApplication {

  @Autowired
  RedisProperties redisProperties;

  public static void main(String[] args) {
    SpringApplication.run(DemoApplication.class, args);
  }

  @PostConstruct
  void init() {
    System.out.println(redisProperties.getTimeout());
  }
}

It printed (parse as 5s):

PT5S

https://docs.oracle.com/javase/8/docs/api//java/time/Duration.html#parse-java.lang.CharSequence-

Answer 2

If your Spring-Boot version or its dependencies don't put ApplicationConversionService into context (and Spring-Boot doesn't until 2.1), you can expose it explicitly

@Bean
public ConversionService conversionService() {
    return ApplicationConversionService.getSharedInstance();
}

It invokes Duration.parse, so you may use PT3S, PT1H30M, etc in properties files.

Answer 3

Any property which is of type duration can be injected via .properties or .yml files. All you need to do is use a proper formatting.

If you want to inject a duration of 5 seconds it should be defined as PT5S or pt5s or PT5s

• case of the letters doesn't matter, so you use any combination which is readable for you
• generally everyone uses all capital letters

Other examples

PT1.5S       = 1.5 Seconds
PT60S        = 60 Seconds
PT3M         = 3 Minutes
PT2H         = 2 Hours
P3DT5H40M30S = 3Days, 5Hours, 40 Minutes and 30 Seconds

You can also use +ve and -ve signs to denote positive vs negative period of time.

• You can negate only one of the entity for example: PT-3H30M = -3 hours, +30 minutes, basically -2.5Hours
• Or You can negate the whole entity: -PT3H30M = -3 hours, -30 minutes, basically -3.5Hours
• Double negative works here too: -PT-3H+30M = +3 Hours, -30 Minutes, basically +2.5Hours

  
  
  

Upvote, if it works for you or you like the explanation. Thanks,

Answer 4

It's possible to use @Value notation with Spring Expression Language

@Value("#{T(java.time.Duration).parse('${spring.redis.timeout}')}")
private Duration timeout;

Answer 5

Spring Boot attempts to coerce the external application properties to the right type when it binds to the @ConfigurationProperties beans. If you need custom type conversion, you can provide a ConversionService bean (with a bean named conversionService)

See: https://docs.spring.io/spring-boot/docs/2.0.4.RELEASE/reference/htmlsingle/#boot-features-external-config-conversion

Create new ApplicationConversionService bean (it must be named conversionService ). Here you are my code tested with Spring boot 2.0.4:

@Configuration
public class Conversion {

@Bean
public ApplicationConversionService conversionService()
{
    final ApplicationConversionService applicationConversionService = new ApplicationConversionService();
    return applicationConversionService;
}

Here you are an example project using this approach:

https://github.com/cristianprofile/spring-data-redis-lettuce