5.9 Bridging Spring AOP

Although Micronaut’s design is based on a compile-time approach and does not rely on Spring dependency injection, there is still a lot of value in the Spring ecosystem that does not depend directly on the Spring container.

You may wish to use existing Spring projects within Micronaut and configure beans to be used within Micronaut.

You may also wish to leverage existing AOP advice from Spring. One example of this is Spring’s support for declarative transactions with @Transactional.

Micronaut provides support for Spring-based transaction management without requiring Spring itself. Simply add the spring module to your application dependencies:

implementation("io.micronaut.spring:micronaut-spring")

<dependency>
    <groupId>io.micronaut.spring</groupId>
    <artifactId>micronaut-spring</artifactId>
</dependency>

This is done by defining a Micronaut Transactional annotation that uses @AliasFor in a manner that every time you set a value with Transactional it aliases the value to the equivalent value in Spring’s version of @Transactional.

The benefit here is you can use Micronaut’s compile-time, reflection-free AOP to declare programmatic Spring transactions. For example:

Using @Transactional

import io.micronaut.spring.tx.annotation.*;
...
@Transactional
public Book saveBook(String title) {
    ...
}