🛳️ 👂🏼 🚴🏿 Spring Data JDBCBaeldungの紹介 👨‍👩‍👦 🥧 🤢

「JavaDeveloper。Professional」コースの将来の学生のために、有用な資料の翻訳

を用意しました。また、「SpringDatajdbcの紹介」というトピックに関する公開レッスンに参加することをお勧めします。

Spring DataJDBCは2018年に発表されました。目標は、Spring Dataの原則に従い続けながら、開発者にJPAのより簡単な代替手段を提供することでした。プロジェクトの背後にある動機について詳しくは、ドキュメントをご覧ください。

この記事では、Spring DataJDBCの使用例をいくつか紹介します。ここには詳細なチュートリアルはありませんが、提供された情報で十分に試してみることができれば幸いです。Spring Data JPAに既に精通している場合は、非常に便利です。ソースコードはgithubにあります。

クイックスタートとして、このテンプレートを使用しました。

準備

data-jdbc

— , flyway

postgres

.

// build.gradle
dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-data-jdbc'

    implementation 'org.flywaydb:flyway-core'

    runtimeOnly 'org.postgresql:postgresql'
}

# application.yml
spring:
  application:
    name: template-app
  datasource:
    url: jdbc:postgresql://localhost:5432/demo_app?currentSchema=app
    username: app_user
    password: change_me
    driver-class-name: org.postgresql.Driver

create table book (
    id varchar(32) not null,
    title varchar(255) not null,
    author varchar(255),
    isbn varchar(15),
    published_date date,
    page_count integer,
    primary key (id)
);

java- ( , @Id

org.springframework.data.annotation.Id

):

// Book.java
public class Book {
    @Id
    private String id;
    private String title;
    private String author;
    private String isbn;
    private Instant publishedDate;
    private Integer pageCount;
}

, :

// BookRepositoryTest.java
@Test
void canSaveBook() {
    var book = Book.builder().author("Steven Erikson").title("Gardens of the Moon").build();
    var savedBook = bookRepository.save(book);

    assertThat(savedBook.getId()).isNotBlank();
    assertThat(savedBook.getAuthor()).isEqualTo(book.getAuthor());
    assertThat(savedBook.getTitle()).isEqualTo(book.getTitle());

    assertThat(savedBook).isEqualTo(bookRepository.findById(savedBook.getId()).get());
}

— ERROR: null value in column "id" violates not-null constraint. , id . Spring Data JDBC Spring Data JPA. ApplicationListener

BeforeSaveEvent

:

// PersistenceConfig.java
@Bean
public ApplicationListener<BeforeSaveEvent> idGenerator() {
    return event -> {
        var entity = event.getEntity();
        if (entity instanceof Book) {
            ((Book) entity).setId(UUID.randomUUID().toString());
        }
    };
}

, Id . .

Spring Data . Spring Data JDBC . BookRepository

:

Optional<Book> findByTitle(String title);

@Test
void canFindBookByTitle() {
    var title = "Gardens of the Moon";
    var book = Book.builder().author("Steven Erikson").title(title).build();
    var savedBook = bookRepository.save(book);
    assertThat(bookRepository.findByTitle(title).get()).isEqualTo(savedBook);
}

— Caused by: java.lang.IllegalStateException: No query specified on findByTitle

. Spring Data JDBC , @Query. sql- :

@Query("select * from Book b where b.title = :title")
Optional<Book> findByTitle(@Param("title") String title);

! .

: Spring Data JDBC 2.0 .

Spring Data JDBC . , . , . - (Domain Driven Design), , , , , .

--

"--" "--" @MappedCollection

. "--". UserAccount

Address

. sql:

create table address
(
    id      varchar(36) not null,
    city    varchar(255),
    state   varchar(255),
    street  varchar(255),
    zipcode varchar(255),
    primary key (id)
);

create table user_account
(
    id         varchar(36)  not null,
    name       varchar(255) not null,
    email      varchar(255) not null,
    address_id varchar(36),
    primary key (id),
    constraint fk_user_account_address_id foreign key (address_id) references address (id)
);

UserAccount

:

// UserAccount.java
public class UserAccount implements GeneratedId {
    // ...other fields
    @MappedCollection(idColumn = "id")
    private Address address;
}

, address

. idColumn

— Address

. , Address

UserAccount

, UserAccount

. :

//UserAccountRepositoryTest.java
@Test
void canSaveUserWithAddress() {
    var address = stubAddress();
    var newUser = stubUser(address);

    var savedUser = userAccountRepository.save(newUser);

    assertThat(savedUser.getId()).isNotBlank();
    assertThat(savedUser.getAddress().getId()).isNotBlank();

    var foundUser = userAccountRepository.findById(savedUser.getId()).orElseThrow(IllegalStateException::new);
    var foundAddress = addressRepository.findById(foundUser.getAddress().getId()).orElseThrow(IllegalStateException::new);

    assertThat(foundUser).isEqualTo(savedUser);
    assertThat(foundAddress).isEqualTo(savedUser.getAddress());
}

--

sql, "--":

create table warehouse
(
    id       varchar(36) not null,
    location varchar(255),
    primary key (id)
);

create table inventory_item
(
    id        varchar(36) not null,
    name      varchar(255),
    count     integer,
    warehouse varchar(36),
    primary key (id),
    constraint fk_inventory_item_warehouse_id foreign key (warehouse) references warehouse (id)
);

(warehouse) / (inventoryitems). Warehouse

@MappedCollection

InventoryItem

:

public class Warehouse {
    // ...other fields
    @MappedCollection
    Set<InventoryItem> inventoryItems = new HashSet<>();

    public void addInventoryItem(InventoryItem inventoryItem) {
        var itemWithId = inventoryItem.toBuilder().id(UUID.randomUUID().toString()).build();
        this.inventoryItems.add(itemWithId);
    }
}

public class InventoryItem {
    @Id
    private String id;
    private String name;
    private int count;
}

id

addInventoryItem

. ApplicationListener

Warehouse

BeforeSaveEvent

, id

InventoryItem

. , . "--". , Warehouse

InventoryItem

.

InventoryItem

Warehouse

. , , . JPA , , . Spring Data JDBC , "--" .

-- --

"--" " ". "--" . . Spring Data JDBC Id

. , .

Spring Data JPA, , , . , Spring Data JDBC , . , , "" (dirty tracking) (session). Spring Data JDBC , ( ) , . , , JPA, , Spring Data JPA Spring Data JDBC.

Spring Data JDBC. , , . , dirty tracking, . , , .

, ! , Spring Data JDBC.

"Java Developer. Professional"

" Spring Data jdbc"

Spring Data JDBCBaeldungの紹介

準備

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