我有下划线的数据库字段。我在驼峰式中有实体字段。我无法更改其中任何一个。

有什么东西，也许是一个类级别的注释，我可以使用默认的实体列名注释到驼峰式等效项？

例如，我有一个这样的实体:

@Entity
public class AuthorisationEntity {

    @Column(name = "non_recoverable")
    private BigDecimal nonRecoverable;

    @Column(name = "supplier_recoverable")
    private BigDecimal supplierRecoverable;

    @Column(name = "refund_amount")
    private BigDecimal refundAmount;

}

我的梦想是:

@Entity
@DatabaseIsUnderscoreAndThisAnnotationConvertsThemToCamelCaseByDefault
public class AuthorisationEntity {

    private BigDecimal nonRecoverable;

    private BigDecimal supplierRecoverable;

    private BigDecimal refundAmount;

}

最佳答案

您可以使用自定义 Hibernate 命名策略来实现此目的。

您需要做的就是使用 hibernate-types 开源项目。

hibernate 5.2 或更高版本

您需要添加以下 Maven 依赖项:

<dependency>
    <groupId>com.vladmihalcea</groupId>
    <artifactId>hibernate-types-52</artifactId>
    <version>${hibernate-types.version}</version>
</dependency>

并设置以下 Hibernate 配置属性:

<property name="hibernate.physical_naming_strategy"
          value="com.vladmihalcea.hibernate.type.util.CamelCaseToSnakeCaseNamingStrategy"
/>

hibernate 5.0 和 5.1

您需要添加以下 Maven 依赖项:

<dependency>
    <groupId>com.vladmihalcea</groupId>
    <artifactId>hibernate-types-5</artifactId>
    <version>${hibernate-types.version}</version>
</dependency>

并设置以下 Hibernate 配置属性:

<property name="hibernate.physical_naming_strategy"
          value="com.vladmihalcea.hibernate.type.util.CamelCaseToSnakeCaseNamingStrategy"
/>

hibernate 4.3

您需要添加以下 Maven 依赖项:

<dependency>
    <groupId>com.vladmihalcea</groupId>
    <artifactId>hibernate-types-43</artifactId>
    <version>${hibernate-types.version}</version>
</dependency>

并设置以下 Hibernate 配置属性:

<property name="hibernate.ejb.naming_strategy"
          value="com.vladmihalcea.hibernate.type.util.CamelCaseToSnakeCaseNamingStrategy"
/>

hibernate 4.2 和 4.1

您需要添加以下 Maven 依赖项:

<dependency>
    <groupId>com.vladmihalcea</groupId>
    <artifactId>hibernate-types-4</artifactId>
    <version>${hibernate-types.version}</version>
</dependency>

并设置以下 Hibernate 配置属性:

<property name="hibernate.ejb.naming_strategy"
          value="com.vladmihalcea.hibernate.type.util.CamelCaseToSnakeCaseNamingStrategy"
/>

测试时间

假设您有以下实体:

@Entity(name = "BookAuthor")
public class BookAuthor {
 
    @Id
    private Long id;
 
    private String firstName;
 
    private String lastName;
 
    //Getters and setters omitted for brevity
}
 
@Entity(name = "PaperBackBook")
public class PaperBackBook {
 
    @Id
    @GeneratedValue(
        strategy = GenerationType.SEQUENCE
    )
    private Long id;
 
    @NaturalId
    private String ISBN;
 
    private String title;
 
    private LocalDate publishedOn;
 
    @ManyToOne(fetch = FetchType.LAZY)
    private BookAuthor publishedBy;
 
    //Getters and setters omitted for brevity
}

当使用 CamelCaseToSnakeCaseNamingStrategy 自定义命名策略时，Hibernate 将使用 hbm2ddl 工具生成以下数据库架构:

CREATE SEQUENCE hibernate_sequence
START WITH 1 INCREMENT BY 1
 
CREATE TABLE book_author (
    id          BIGINT NOT NULL,
    first_name  VARCHAR(255),
    last_name   VARCHAR(255),
    PRIMARY KEY (id)
)
 
CREATE TABLE paper_back_book (
    id              BIGINT NOT NULL,
    isbn            VARCHAR(255),
    published_on    DATE, 
    title           VARCHAR(255),
    published_by_id BIGINT, 
    PRIMARY KEY (id)
)

很酷，对吧？

关于java - 如何使用camelCase将Hibernate实体字段映射到snake_case(下划线)数据库标识符，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/25681386/