Spring configuration

Spring configuration

1. To obtain Environment variables

   • You can Inject Environment with @Autowired
     • and call environment.getProperty("PROP_NAME")
   • You can use @Value annotation
     • can be use in fields or methos parameters
     • @Value("${environmentName}")

2. @Profile

   • Method
   • Class
   • Multiples profiles can be active
   • is equivalent to profile attribute on <beans> tag, <beans> tags can be nested
     • Profile attribute not work on tag <bean>

3. @Configuration

   • Defines a configuration class
   • Are subclassed at startup-time with CGLIB
     • Configuration class should not be final
   • You can use @Import
     • To split @Configurations in multiples class
   • @PropertySource
     • Additional property sources
     • @Configuration @PropertySource("classpath:/com/exampleconfig/application.properties") public class ApplicationConfiguration {
   • Can be mixed with @ComponentScan
     • But component scanning can work without @Configuration
       • <context:component-scan base-package="br.com.softplan">

4. Spring Expression language (SPEL)

   • can be used in @Value annotation values
   • ${} is for properties
   • #{} is for SpEL
   • Access property of bean #{beanName.property}
   • systemProperties
   • systemEnvironment
   • Used in spring Security and batch

5. @EnableAutoConfguration

   • Springboot automatically attempts to configure yout application based on the jar dependencies that you have added
     • You should only ever add one @SpringBootApplication or @EnableAutoConfiguration annotation.
       • in your main class with @Configuration