\uc548\ub155\ud558\uc138\uc694! \uc774\ubc88 \uae00\uc5d0\uc11c\ub294 \uc2a4\ud504\ub9c1 \ubd80\ud2b8 \ubc31\uc5d4\ub4dc \uac1c\ubc1c\uc744 \uc704\ud55c \ud074\ub798\uc2a4\uc778 \uc5d4\ud2f0\ud2f0 \ub9e4\ub2c8\uc800\ub294 JPA\uc758 \ud575\uc2ec \uc778\ud130\ud398\uc774\uc2a4\ub85c, \uc5d4\ud2f0\ud2f0\uc758 \uc218\uba85 \uc8fc\uae30\ub97c \uad00\ub9ac\ud558\uace0 \ub370\uc774\ud130\ubca0\uc774\uc2a4\uc758 CRUD(Create, Read, Update, Delete) \uc791\uc5c5\uc744 \ucc98\ub9ac\ud558\ub294 \ub370 \uc0ac\uc6a9\ub429\ub2c8\ub2e4. \uc27d\uac8c \ub9d0\ud574, \uc5d4\ud2f0\ud2f0 \ub9e4\ub2c8\uc800\ub294 \uc560\ud50c\ub9ac\ucf00\uc774\uc158\uacfc \ub370\uc774\ud130\ubca0\uc774\uc2a4 \uac04\uc758 \ubaa8\ub4e0 \uc0c1\ud638\uc791\uc6a9\uc744 \ub2f4\ub2f9\ud558\ub294 \uc911\uc7ac\uc790 \uc5ed\ud560\uc744 \ud569\ub2c8\ub2e4.<\/p>\n \uc5d4\ud2f0\ud2f0 \ub9e4\ub2c8\uc800\ub294 \uc5d4\ud2f0\ud2f0\uc758 \uc0c1\ud0dc\ub97c \uad00\ub9ac\ud569\ub2c8\ub2e4. JPA\uc5d0\uc11c \uc5d4\ud2f0\ud2f0\ub294 \ub2e4\uc74c\uacfc \uac19\uc740 \uc0c1\ud0dc\ub97c \uac00\uc9d1\ub2c8\ub2e4:<\/p>\n \uc5d4\ud2f0\ud2f0 \ub9e4\ub2c8\uc800\ub294 \uc5d4\ud2f0\ud2f0\uc758 \uc0dd\uc131, \uc870\ud68c, \uc218\uc815, \uc0ad\uc81c \uc791\uc5c5\uc744 \ubaa8\ub450 \ucc98\ub9ac\ud569\ub2c8\ub2e4. \uac01\uac01\uc758 \uc791\uc5c5\uc740 \ub2e4\uc74c\uacfc \uac19\uc774 \uc218\ud589\ub429\ub2c8\ub2e4:<\/p>\n \uc5d4\ud2f0\ud2f0 \ub9e4\ub2c8\uc800\ub294 \uc5ec\ub7ec \uc720\uc6a9\ud55c \uba54\uc18c\ub4dc\ub97c \uc81c\uacf5\ud569\ub2c8\ub2e4. \uc5ec\uae30\uc11c\ub294 \uac00\uc7a5 \ub9ce\uc774 \uc0ac\uc6a9\ub418\ub294 \uc8fc\uc694 \uba54\uc18c\ub4dc\ub97c \uc54c\uc544\ubcf4\uaca0\uc2b5\ub2c8\ub2e4.<\/p>\n \uc2a4\ud504\ub9c1 \ubd80\ud2b8\uc5d0\uc11c\ub294 \ud2b8\ub79c\uc7ad\uc158 \uad00\ub9ac\ub294 \uc2a4\ud504\ub9c1\uc758 \uc5d4\ud2f0\ud2f0 \ub9e4\ub2c8\uc800 \ud329\ud1a0\ub9ac\ub294 \uc5d4\ud2f0\ud2f0 \ub9e4\ub2c8\uc800\ub97c \uc0dd\uc131\ud558\ub294 \ub370 \ud544\uc694\ud55c \uc124\uc815 \uc815\ubcf4\ub97c \uc81c\uacf5\ud569\ub2c8\ub2e4. \uc2a4\ud504\ub9c1 \ubd80\ud2b8\uc5d0\uc11c\ub294 \uc8fc\ub85c application.properties \ub610\ub294 application.yml \ud30c\uc77c\uc5d0 \ub370\uc774\ud130\ubca0\uc774\uc2a4 \uc5f0\uacb0 \uc815\ubcf4\ub97c \uc124\uc815\ud569\ub2c8\ub2e4.<\/p>\n \uc5d4\ud2f0\ud2f0 \ub9e4\ub2c8\uc800\ub294 \ub2e4\uc74c\uacfc \uac19\uc740 \uc5ec\ub7ec \uac00\uc9c0 \uc7a5\uc810\uc744 \uc81c\uacf5\ud569\ub2c8\ub2e4:<\/p>\n \uc5d4\ud2f0\ud2f0 \ub9e4\ub2c8\uc800\ub97c \uc0ac\uc6a9\ud560 \ub54c \uc8fc\uc758\ud574\uc57c \ud560 \uc0ac\ud56d\ub4e4\ub3c4 \uc788\uc2b5\ub2c8\ub2e4:<\/p>\n \uc774\ubc88 \uae00\uc5d0\uc11c\ub294 \uc5d4\ud2f0\ud2f0 \ub9e4\ub2c8\uc800\uc5d0 \ub300\ud574 \uc54c\uc544\ubcf4\uace0 \uc2a4\ud504\ub9c1 \ubd80\ud2b8 \ubc31\uc5d4\ub4dc \uac1c\ubc1c\uc5d0\uc11c\uc758 \uc0ac\uc6a9 \ubc29\ubc95\uc5d0 \ub300\ud574 \uc0b4\ud3b4\ubcf4\uc558\uc2b5\ub2c8\ub2e4. \uc5d4\ud2f0\ud2f0 \ub9e4\ub2c8\uc800\ub294 JPA\uc758 \ud575\uc2ec \uc694\uc18c\ub85c, \ub370\uc774\ud130\uc758 \uc601\uc18d\uc131\uc744 \uad00\ub9ac\ud558\uace0, CRUD \uc791\uc5c5\uc744 \uac04\uc18c\ud654\ud558\ub294 \ub370 \ud070 \ub3c4\uc6c0\uc744 \uc90d\ub2c8\ub2e4. \uc2a4\ud504\ub9c1 \ubd80\ud2b8\ub97c \uc774\uc6a9\ud55c \ubc31\uc5d4\ub4dc \uac1c\ubc1c \uacfc\uc815\uc5d0\uc11c \uc5d4\ud2f0\ud2f0 \ub9e4\ub2c8\uc800\ub97c \uc798 \ud65c\uc6a9\ud558\uc5ec \ud6a8\uc728\uc801\uc774\uace0 \uc720\uc9c0 \ubcf4\uc218 \uac00\ub2a5\ud55c \uc560\ud50c\ub9ac\ucf00\uc774\uc158\uc744 \ub9cc\ub4dc\ub294 \ub370 \uae30\uc5ec\ud558\uc2dc\uae38 \ubc14\ub78d\ub2c8\ub2e4.<\/p>\nEntityManager<\/code>\uc5d0 \ub300\ud574 \uc790\uc138\ud788 \uc54c\uc544\ubcf4\uaca0\uc2b5\ub2c8\ub2e4. \uc5d4\ud2f0\ud2f0 \ub9e4\ub2c8\uc800\ub294 JPA(Java Persistence API)\uc5d0\uc11c \uc911\uc694\ud55c \uc5ed\ud560\uc744 \ud558\uba70, \ub370\uc774\ud130\ubca0\uc774\uc2a4\uc640\uc758 \uc0c1\ud638\uc791\uc6a9\uc744 \ub2e8\uc21c\ud654\ud574\uc90d\ub2c8\ub2e4. \uc774 \uae00\uc744 \ud1b5\ud574 \uc5d4\ud2f0\ud2f0 \ub9e4\ub2c8\uc800\uc758 \uc815\uc758, \uae30\ub2a5, \uc0ac\uc6a9 \ubc29\ubc95, \uadf8\ub9ac\uace0 \uc2a4\ud504\ub9c1 \ubd80\ud2b8\uc640\uc758 \ud1b5\ud569 \ubc29\ubc95\uc744 \uae4a\uc774 \uc788\uac8c \uc0b4\ud3b4\ubcf4\uaca0\uc2b5\ub2c8\ub2e4.<\/p>\n1. \uc5d4\ud2f0\ud2f0 \ub9e4\ub2c8\uc800\ub780?<\/h2>\n
1.1. \uc218\uba85 \uc8fc\uae30 \uad00\ub9ac<\/h3>\n
\n
1.2. CRUD \uc791\uc5c5 \ucc98\ub9ac<\/h3>\n
EntityManager em = entityManagerFactory.createEntityManager();\nem.getTransaction().begin();\n\n\/\/ Create\nMyEntity entity = new MyEntity();\nem.persist(entity);\n\n\/\/ Read\nMyEntity foundEntity = em.find(MyEntity.class, entityId);\n\n\/\/ Update\nfoundEntity.setProperty(value);\nem.merge(foundEntity);\n\n\/\/ Delete\nem.remove(foundEntity);\n\nem.getTransaction().commit();<\/code><\/pre>\n2. \uc5d4\ud2f0\ud2f0 \ub9e4\ub2c8\uc800\uc758 \uc8fc\uc694 \uba54\uc18c\ub4dc<\/h2>\n
2.1. persist()<\/h3>\n
persist()<\/code> \uba54\uc18c\ub4dc\ub294 \uc0c8\ub85c\uc6b4 \uc5d4\ud2f0\ud2f0\ub97c \uc601\uc18d\uc131 \ucee8\ud14d\uc2a4\ud2b8\uc5d0 \ucd94\uac00\ud569\ub2c8\ub2e4. \uc774 \uba54\uc18c\ub4dc\ub97c \ud638\ucd9c\ud558\uba74 \uc5d4\ud2f0\ud2f0\uac00 Managed<\/strong> \uc0c1\ud0dc\ub85c \uc804\ud658\ub429\ub2c8\ub2e4.<\/p>\n2.2. find()<\/h3>\n
find()<\/code> \uba54\uc18c\ub4dc\ub294 \uc8fc\uc5b4\uc9c4 ID\ub85c \uc5d4\ud2f0\ud2f0\ub97c \uc870\ud68c\ud569\ub2c8\ub2e4. \ucc3e\uc740 \uc5d4\ud2f0\ud2f0\uac00 \uc5c6\uc73c\uba74 null<\/code>\uc744 \ubc18\ud658\ud569\ub2c8\ub2e4.<\/p>\n2.3. merge()<\/h3>\n
merge()<\/code> \uba54\uc18c\ub4dc\ub294 \uc8fc\uc5b4\uc9c4 \uc5d4\ud2f0\ud2f0\ub97c \uc601\uc18d\uc131 \ucee8\ud14d\uc2a4\ud2b8\uc5d0 \ubcd1\ud569\ud558\uc5ec Managed<\/strong> \uc0c1\ud0dc\ub85c \uc804\ud658\ud569\ub2c8\ub2e4. \uae30\uc874 \uc5d4\ud2f0\ud2f0\uac00 \uc5c5\ub370\uc774\ud2b8\ub41c \uacbd\uc6b0, DB\uc5d0\ub3c4 \ubc18\uc601\ub429\ub2c8\ub2e4.<\/p>\n2.4. remove()<\/h3>\n
remove()<\/code> \uba54\uc18c\ub4dc\ub294 \uc8fc\uc5b4\uc9c4 \uc5d4\ud2f0\ud2f0\ub97c \uc0ad\uc81c\ud569\ub2c8\ub2e4. \uc774 \uba54\uc18c\ub4dc\ub97c \ud638\ucd9c\ud558\uba74 \uc5d4\ud2f0\ud2f0\uac00 Removed<\/strong> \uc0c1\ud0dc\ub85c \ud45c\uc2dc\ub429\ub2c8\ub2e4.<\/p>\n3. \uc2a4\ud504\ub9c1 \ubd80\ud2b8\uc640 \uc5d4\ud2f0\ud2f0 \ub9e4\ub2c8\uc800<\/h2>\n
EntityManager<\/code>\ub97c \uc27d\uac8c \uc0ac\uc6a9\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \uc77c\ubc18\uc801\uc73c\ub85c @PersistenceContext<\/code> \uc5b4\ub178\ud14c\uc774\uc158\uc744 \uc0ac\uc6a9\ud558\uc5ec \uc5d4\ud2f0\ud2f0 \ub9e4\ub2c8\uc800\ub97c \uc8fc\uc785\ubc1b\uc2b5\ub2c8\ub2e4.<\/p>\n@Autowired\nprivate EntityManagerFactory entityManagerFactory;\n\npublic void someMethod() {\n EntityManager em = entityManagerFactory.createEntityManager();\n em.getTransaction().begin();\n\n \/\/ \uc5d4\ud2f0\ud2f0 \uc791\uc5c5 \uc218\ud589...\n\n em.getTransaction().commit();\n}<\/code><\/pre>\n3.1. @PersistenceContext<\/h3>\n
EntityManager<\/code>\ub97c \uc790\ub3d9\uc73c\ub85c \uc8fc\uc785\ubc1b\uae30 \uc704\ud574 @PersistenceContext<\/code> \uc5b4\ub178\ud14c\uc774\uc158\uc744 \uc0ac\uc6a9\ud560 \uc218 \uc788\uc73c\uba70, \uc544\ub798\uc640 \uac19\uc774 \uc124\uc815\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4:<\/p>\n@PersistenceContext\nprivate EntityManager entityManager;<\/code><\/pre>\n3.2. \ud2b8\ub79c\uc7ad\uc158 \uad00\ub9ac<\/h3>\n
@Transactional<\/code> \uc5b4\ub178\ud14c\uc774\uc158\uc744 \ud1b5\ud574 \uc27d\uac8c \ucc98\ub9ac\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \uc774 \uc5b4\ub178\ud14c\uc774\uc158\uc744 \uba54\uc18c\ub4dc \uc704\uc5d0 \ubd99\uc774\uba74 \uc790\ub3d9\uc73c\ub85c \ud2b8\ub79c\uc7ad\uc158\uc774 \uad00\ub9ac\ub429\ub2c8\ub2e4.<\/p>\n@Transactional\npublic void someTransactionalMethod() {\n MyEntity entity = new MyEntity();\n entityManager.persist(entity);\n \/\/ ... \ucd94\uac00 \uc791\uc5c5 ...\n}<\/code><\/pre>\n4. \uc5d4\ud2f0\ud2f0 \ub9e4\ub2c8\uc800 \ud329\ud1a0\ub9ac\uc640 \uc124\uc815<\/h2>\n
spring.datasource.url=jdbc:mysql:\/\/localhost:3306\/mydb\nspring.datasource.username=myuser\nspring.datasource.password=mypassword\nspring.jpa.hibernate.ddl-auto=update\nspring.jpa.show-sql=true<\/code><\/pre>\n5. \uc5d4\ud2f0\ud2f0 \ub9e4\ub2c8\uc800\uc758 \uc7a5\uc810<\/h2>\n
\n
6. \uc5d4\ud2f0\ud2f0 \ub9e4\ub2c8\uc800 \uc0ac\uc6a9 \uc2dc \uc8fc\uc758\uc0ac\ud56d<\/h2>\n
\n
7. \ub9c8\ubb34\ub9ac<\/h2>\n
7.1. \ucc38\uace0 \uc790\ub8cc<\/h3>\n