What is the Spring equivalent to FactoryModuleBuilder, @AssistedInject, and @Assisted in Guice?

问题

What is the Spring Framework equivalent to FactoryModuleBuilder, @AssistedInject, and @Assisted in Google Guice? In other words, what is the recommended approach using Spring to create factory objects whose methods accept arguments that the application (not the container) must provide?

The Spring static factory method is not the same as FactoryModuleBuilder. FactoryModuleBuilder builds a Guice module that generates "factories" that implement the Factory Method Pattern. Unlike a Spring static factory method, the methods of these factory objects are instance methods, not static methods. The problem with a static factory method is that it is static and doesn't implement an interface so it cannot be replaced with an alternative factory implementation. Different FactoryModuleBuilder instances, however, can build different factories that implement the same interface.

回答1:

Spring has no equivalent to the Guice FactoryModuleBuilder. The closest equivalent would be a Spring @Configuration class that provides a factory bean that implements a factory interface whose methods accept arbitrary arguments from the application. The Spring container could inject dependencies into the @Configuration object that it, in turn, could supply to the factory constructor. Unlike with FactoryModuleBuilder, the Spring approach produces a lot of boilerplate code typical of factory implementations.

Example:

public class Vehicle {
}

public class Car extends Vehicle {
    private final int numberOfPassengers;

    public Car(int numberOfPassengers) {
        this.numberOfPassengers = numberOfPassengers;
    } 
}

public interface VehicleFactory {
    Vehicle createPassengerVehicle(int numberOfPassengers);
}

@Configuration
public class CarFactoryConfiguration {
    @Bean
    VehicleFactory carFactory() {
        return new VehicleFactory() {
            @Override
            Vehicle createPassengerVehicle(int numberOfPassengers) {
                return new Car(numberOfPassengers);
            }
        };
    }
}

回答2:

I'm not entirely certain that this question is a dupe, (only 90% sure), but this answer:

https://stackoverflow.com/a/13243066/1768232

Seems to have the information you need. Specifically, you should do this:

I got it working by fetching an instance of the bean used in the constructor-arg out of the context and then populating it with the values that you are working with at run-time. This bean will then be used as the parameter when you get your factory-generated bean.

public class X {
   public void callFactoryAndGetNewInstance() {
      User user = context.getBean("user");
      user.setSomethingUsefull(...);
      FileValidator validator = (FileValidator)context.getBean("fileValidator");
      ...
   }
}

I recommend reading the entire answer.

来源：https://stackoverflow.com/questions/29555705/what-is-the-spring-equivalent-to-factorymodulebuilder-assistedinject-and-ass

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java

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Guice