这是一个非常常见的要求,因此我决定写一篇非常详细的文章,介绍使用JPA和Hibernate时映射JSON列类型的最佳方法。
您需要做的第一件事是在项目配置文件中设置以下Hibernate Types Maven依赖项pom.xml
:
<dependency>
<groupId>com.vladmihalcea</groupId>
<artifactId>hibernate-types-52</artifactId>
<version>${hibernate-types.version}</version>
</dependency>
假设您具有以下实体:
@Entity(name = "Book")
@Table(name = "book")
@TypeDef(
typeClass = JsonBinaryType.class,
defaultForType = JsonNode.class
)
public class Book {
@Id
@GeneratedValue
private Long id;
@NaturalId
private String isbn;
@Column(columnDeFinition = "jsonb")
private JsonNode properties;
//Getters and setters omitted for brevity
}
请注意,@TypeDef
用来指示Hibernate JsonNode
使用JsonBinaryType
Hibernate Types项目提供的内容来映射对象。
现在,如果您保存实体:
Book book = new Book();
book.setIsbn( "978-9730228236" );
book.setProperties(
JacksonUtil.toJsonNode(
"{" +
" \"title\": \"High-Performance Java Persistence\"," +
" \"author\": \"Vlad Mihalcea\"," +
" \"publisher\": \"Amazon\"," +
" \"price\": 44.99" +
"}"
)
);
entityManager.persist( book );
INSERT INTO
book
(
isbn,
properties,
id
)
VALUES
(
'978-9730228236',
'{"title":"High-Performance Java Persistence","author":"Vlad Mihalcea","publisher":"Amazon","price":44.99}',
1
)
您还可以将其加载回并修改它:
Session session = entityManager.unwrap( Session.class );
Book book = session
.bySimpleNaturalId( Book.class )
.load( "978-9730228236" );
LOGGER.info( "Book details: {}", book.getProperties() );
book.setProperties(
JacksonUtil.toJsonNode(
"{" +
" \"title\": \"High-Performance Java Persistence\"," +
" \"author\": \"Vlad Mihalcea\"," +
" \"publisher\": \"Amazon\"," +
" \"price\": 44.99," +
" \"url\": \"https://www.amazon.com/High-Performance-Java-Persistence-Vlad-Mihalcea/dp/973022823X/\"" +
"}"
)
);
Hibernate UPDATE
为您处理以下声明:
SELECT b.id AS id1_0_
FROM book b
WHERE b.isbn = '978-9730228236'
SELECT b.id AS id1_0_0_ ,
b.isbn AS isbn2_0_0_ ,
b.properties AS properti3_0_0_
FROM book b
WHERE b.id = 1
-- Book details: {"price":44.99,"title":"High-Performance Java Persistence","author":"Vlad Mihalcea","publisher":"Amazon"}
UPDATE
book
SET
properties = '{"title":"High-Performance Java Persistence","author":"Vlad Mihalcea","publisher":"Amazon","price":44.99,"url":"https://www.amazon.com/High-Performance-Java-Persistence-Vlad-Mihalcea/dp/973022823X/"}'
WHERE
id = 1