Bean 만들기

HelloConfiguration.java

import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;


class Person {
    private String name;
    private int age;
    private Address address;

    public Person(String name, int age, Address address) {
        this.name = name;
        this.age = age;
        this.address = address;
    }

    public Address getAddress() {
        return this.address;
    }

    public String getName() {
        return this.name;
    }

    public int getAge() {
        return this.age;
    }
}


class Address {
    private String street;

    public Address(String street) {
        this.street = street;
    }

    public String getStreet() {
        return this.street;
    }
}


@Configuration
public class HelloConfiguration {
    @Bean(name = "name")
    public String name() {
        return "Ranga";
    }

    @Bean
    public int age() {
        return 15;
    }

    @Bean
    @Qualifier("myAddress") // 명시적으로 이 bean 을 사용하라고 지정할 수 있도록 Qualifier 를 부여해 둠
    public Address address() {
        return new Address("Main st. 1");
    }

    @Bean
    @Primary // Address bean 이 2개 이상일 때, 이것을 default 로 함
    public Address address2() {
        return new Address("Sub st. 2");
    }

    @Bean
    public Person person(String name, int age, @Qualifier("myAddress") Address address) {
        return new Person(name, age, address);
    }
}

 

 

HelloMain.java

import org.springframework.context.annotation.AnnotationConfigApplicationContext;

import java.util.Arrays;


public class HelloMain {
    public static void main(String[] args) {
        try (AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(HelloConfiguration.class)) {
            String name = context.getBean("name", String.class);
            System.out.println(name);

            Integer age = context.getBean("age", Integer.class);
            System.out.println(age);

            Person person = context.getBean(Person.class);
            System.out.println(person.getAddress().getStreet());

//        Arrays.stream(context.getBeanDefinitionNames()).forEach(System.out::println);           
        }
    }
}