Advanced Kotlin Techniques for Spring Developers
The webinar was offered by JetBrains, you can also find the recording on
their YouTube channel.
Validation
- JSR 305 compiler option for kotlin adds @NotNull annotations for
kotlin non-nullables ` -Xjsr305=strict`
JPA
- Gradle plugin for Kotlin JPA generates no arg constructor
- hashCode should return technical id -> something i saw the first time,
usually you see the typcial calculate all attributes one
- data class is not only a bad idea because of immutability but also
because of the unnecessary methods created for this usecase
Extensions
- there are kotlin extensions for the most common parts in the spring
framework already e.g. query for Spring JDBC
- bean/s function allows DSL bean registration, but is not a replacement for
@Bean methods in Spring Boot
fun main(args: Array<String>) {
runApplication<DemoApplication>(*args) {
addInitializers(
beans {
// Define your bean with Kotlin DSL here
}
)
}
}
Security
- ref
can also be used to transform security DSL into a more kotlinish DSL (also
works in beans block, could also be just return value for
@Bean
annotated method)
val http = ref<HttpSecurity>()
http {
csrf {
disable()
}
}
http.build()
ref generally also works outside of spring and is a kotlin builtin feature