在 Spring 启动应用程序中实例化 @Service @Transactional class 的多个 bean

Question

I am relatively new to Spring boot. I am working on a spring boot application, where I need to inject two different beans for the same POJO.

As of now, I have a service class as follows:

@Service
@Transactional
public class StudentServiceImpl implements StudentService {

  private final StudentHelper studentHelper;
  private final Validator validator;


  public StudentServiceImpl(
      StudentHelper studentHelper,
      Validator validator) {
    this.studentHelper = studentHelper;
    this.validator = validator;
  }

  @Override
  public List<Student> generateReport(String courseId) {
     ...
     if(validator != null) {
         validator.validate(courseId);
     }
     ...
  }

Now, I would like to instantiate two different beans for the same POJO: StudentServiceImpl , one with a proper validator and another with a validator as null. Actually StudentServiceImpl is being used from two flows: One, called from a resource where a validator is required, and in another, called from scheduler where it is not required.

In this regard, I have seen multiple examples, but I am not getting a clue how to do that for making two beans where one is to be used as Transactional Service class as mentioned above and another to be used as a simple component.

Basically, I could figure out that, I have to write a config as follows:

@Configuration
public class StudentServiceConfig {

    @Bean   //THIS BEAN IS TO BE USED AS TRANSACTIONAL SERVICE AS MENTIONED ABOVE
    public StudentServiceImpl studentServiceOne(StudentHelper helper, Validator validator) {
        return new StudentServiceImpl(helper, validator);
    }

    @Bean
    public StudentServiceImpl studentServiceTwo(StudentHelper helper) {
        return new StudentServiceImpl(helper, null);
    }
}

Here, as I mentioned above, I am not getting any clue regarding how to make one of the bean as @Service @Transactional , which is to be called from the resource. Could anyone please help here? Thanks.

Answer 1

You don't need to declare @Service on the class as that is used for auto detecting beans when you don't have @Bean configurations.

For transactions, you can omit @Transactional from class and achieve the same functionality by manually creating proxy class for adding transaction while adding @Bean declaration. Refer to following:

Spring @Transactional on @Bean declaration instead of class Implementation