Spring Boot) could not initialize proxy - no Session 에러 해결

Ex) 

failed to lazily initialize a collection of role: com.test.jpa.jpaProj.domain.Publisher.books, could not initialize proxy - no Session
org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.test.jpa.jpaProj.domain.Publisher.books, could not initialize proxy - no Session
at app//org.hibernate.collection.internal.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:614)
at app//org.hibernate.collection.internal.AbstractPersistentCollection.withTemporarySessionIfNeeded(AbstractPersistentCollection.java:218)
at app//org.hibernate.collection.internal.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:591)
at app//org.hibernate.collection.internal.AbstractPersistentCollection.read(AbstractPersistentCollection.java:149)

해결 방법

: JPA에서 lazy loading기능이 제대로 설정되지 않아 트랜잭션 에러가 발생하여 에러 나는 부분의 메소드를 @Transactional로 감싸준다. 또는 순환 참조되는 엔티티의 필드에 @exclude를 적용

 

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Reference

https://cantcoding.tistory.com/78

JPA/ could not initialize proxy - no Session