[Spring] 스프링 빈 조회 - 기본

스프링 컨테이너에서 스프링 빈을 찾는 가장 기본적인 조회 방법

• 'ac.getBean(빈이름, 타입)'
• 'ac.getBean(타입)'
• 조회 대상 스프링 빈이 없으면 예외 발생
  • 'NoSuchBeanDefinitionException : No bean named 'xxxxx' available'

 

ApplicationContextBasicFindTest.java 를 생성

 

"예제 코드"

package hello.core.beanFind;

import hello.core.AppConfig;
import hello.core.member.MemberService;
import hello.core.member.MemberServiceImpl;
import org.assertj.core.api.Assertions;
import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.NoSuchBeanDefinitionException;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;

import static org.assertj.core.api.Assertions.*;
import static org.junit.jupiter.api.Assertions.assertThrows;

class ApplicationContextBasicFindTest {

    AnnotationConfigApplicationContext ac = new AnnotationConfigApplicationContext(AppConfig.class);

    @Test
    @DisplayName("빈 이름으로 조회")
    void findBeanByName() {
        MemberService memberService = ac.getBean("memberService", MemberService.class);
//        System.out.println("memberService = " + memberService);
//        System.out.println("memberService.getClass() = " + memberService.getClass());
        assertThat(memberService).isInstanceOf(MemberServiceImpl.class);

    }

    // 역할에 의존
    @Test
    @DisplayName("이름 없이 타입으로만 조회")
    void findBeanByType() {
        MemberService memberService = ac.getBean(MemberService.class);
        assertThat(memberService).isInstanceOf(MemberServiceImpl.class);
    }

    // 구현에 의존
    @Test
    @DisplayName("구체 타입으로 조회")
    void findBeanByName2() {
        MemberService memberService = ac.getBean("memberService", MemberServiceImpl.class);
        assertThat(memberService).isInstanceOf(MemberServiceImpl.class);

    }

    // 오류가 터져야 성공한 케이스
    @Test
    @DisplayName("빈 이름으로 조회X")
    void findBeanByNameX() {
        // ac.getBean("xxxx", MemberService.class);
//        MemberService xxxxx = ac.getBean("xxxxx", MemberService.class);
        assertThrows(NoSuchBeanDefinitionException.class,
                () -> ac.getBean("xxxxx", MemberService.class));
    }
}