1 분 소요

JPA로 자바 오브젝트로 저장하기?

  • Hibernate/JPA CRUD (4)

    Sample App Features

  • Create a new Student
  • Read a Student
  • Update a Student
  • Delete a Student

Student Data Access Object

  • Responsible for interfacing with the database
  • This is a common design pattern: DataAccessObject(DAO)
  • Our DAO needs a JPA Entity Manager
  • JPA Entity Manager is the main component for saving/retrieving entities

    JPA Entity Manager

  • Our JPA Entity Manager needs a Data Source
  • The Data Source defines database connection info
  • JPA Entity Manager and Data Source are automatically created by Spring Boot
    • Based on the file: application.properties(JDBC URL, user id, password, etc…)
  • We can autowire/inject the JPA Entity Manager into out Student DAO

Student DAO

  • Step 1: Define DAO interface
  • Step 2: Define DAO implementation
    • Inject the entity manager
  • Step 3: Update main app

Step 1: Define DAO interface

public interface StudentDAO {  
    void save(Student theStudent);  
}

Step 2: Define DAO implementation

Step 3: Update main app

Spring @Transactional

  • Spring provides an @Transactional annotation
  • Automagically begin and end a transaction for your JPA code
    • No need for you to explicitly do this in your code
  • This Spring magic happens behind the scenes

Specialized Annotation for DAOs

  • Spring provides the @Repository annotation
  • Applied to DAO implementations
  • Spring will automatically register the DAO implementation
    • thanks to component-scanning
  • Spring also provides translation of any JDBC related exceptions

Transactions 간략히 보기

The @Transactional annotation is the metadata that specifies the semantics of the transactions on a method. We have two ways to rollback a transaction: declarative and programmatic.

In the declarative approach, we annotate the methods with the @Transactional annotation. The @Transactional annotation makes use of the attributes rollbackFor or rollbackForClassName to rollback the transactions, and the attributes noRollbackFor or noRollbackForClassName to avoid rollback on listed exceptions.

출처 : 유데미, luv2code.com, https://www.baeldung.com/transaction-configuration-with-jpa-and-spring

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