Lombok과 최신 트렌드

롬복과 최신 트렌드

막상 개발을 해보면, 대부분이 다 불변이고, 그래서 다음과 같이 필드에 final 키워드를 사용하게 된다.

그런데 생성자도 만들어야 하고, 주입 받은 값을 대입하는 코드도 만들어야 하고…

필드 주입처럼 좀 편리하게 사용하는 방법은 없을까?

다음 기본 코드를 최적화해보자.

 

OrderServiceImpl - 원래 코드

@Component
public class OrderServiceImpl implements OrderService {
	private final MemberRepository memberRepository;
	private final DiscountPolicy discountPolicy;

	@Autowired
	public OrderServiceImpl(MemberRepository memberRepository, DiscountPolicy discountPolicy) {
		this.memberRepository = memberRepository;
		this.discountPolicy = discountPolicy;
	}

}

 

생성자가 딱 1개만 있으면 @Autowired 를 생략할 수 있다.

@Component
public class OrderServiceImpl implements OrderService {
	private final MemberRepository memberRepository;
	private final DiscountPolicy discountPolicy;

	public OrderServiceImpl(MemberRepository memberRepository, DiscountPolicy discountPolicy) {
		this.memberRepository = memberRepository;
		this.discountPolicy = discountPolicy;
	}

}

 

 

롬복을 이제 적용한다.

 

# 의존성 추가 - build.gradle

plugins {
    id 'java'
    id 'org.springframework.boot' version '2.7.16'
    id 'io.spring.dependency-management' version '1.0.15.RELEASE'
}

group = 'inflearn'
version = '0.0.1-SNAPSHOT'

java {
    sourceCompatibility = '11'
}

//lombok 설정 추가 시작
configurations {
    compileOnly {
        extendsFrom annotationProcessor
    }
}

repositories {
    mavenCentral()
}

dependencies {
    implementation 'org.springframework.boot:spring-boot-starter'
    implementation 'org.junit.jupiter:junit-jupiter:5.8.1'
    testImplementation 'org.springframework.boot:spring-boot-starter-test'

    //lombok 라이브러리 추가 시작
    compileOnly 'org.projectlombok:lombok'
    annotationProcessor 'org.projectlombok:lombok'
    testCompileOnly 'org.projectlombok:lombok'
    testAnnotationProcessor 'org.projectlombok:lombok'
    //lombok 라이브러리 추가 끝
}

tasks.named('test') {
    useJUnitPlatform()
}

 

롬복 라이브러리가 제공하는 @RequiredArgsConstructor 기능을 사용하면 final이 붙은 필드를 모아서
생성자를 자동으로 만들어준다. (다음 코드에는 보이지 않지만 실제 호출 가능하다.)

 

수정 후 최종 결과 코드

@Component
@RequiredArgsConstructor
public class OrderServiceImpl implements OrderService {
	private final MemberRepository memberRepository;
	private final DiscountPolicy discountPolicy;
}

 

public OrderServiceImpl(MemberRepository memberRepository, DiscountPolicy discountPolicy) {
	
    this.memberRepository = memberRepository;
	this.discountPolicy = discountPolicy;
}

 

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정리