Hibernate 无法将 UUID 插入 VARCHAR 列

Question

我正在努力建立一个 MySQL 数据库并在后端使用 Hibernate 和 Play Framework。我对条目 ID 有疑问。我将我的 id 列定义为 VARCHAR(36):

CREATE TABLE `logaritmical`.`users` (
   `id` VARCHAR(36) NOT NULL,
   `username` TEXT NOT NULL,
    `email` TEXT NOT NULL,
    PRIMARY KEY (`id`),
    UNIQUE INDEX `id_UNIQUE` (`id` ASC)
);

现在，@Entityclass是这样的：

@Entity
@Table(name = "users")
public class UserDO {

   @Id
   @GeneratedValue(generator = "uuid2")
   @GenericGenerator(name = "uuid2", strategy = "uuid2")
   @Column(name = "id", updatable = false, nullable = false, columnDefinition = "VARCHAR(36)")
   private UUID id;
    
   @Column
   private String username;
    
   @Column
   private String email;
}

插入时出现以下错误：Incorrect string value: '\xEF\xA5!\x89\xF3K...' for column 'id' at row 1

如果我将列类型和 columnDefinition 更改为 BINARY(16)，则插入有效，但缺点是在进行选择时 ID 不可读。

附加信息： persistence.xml 看起来像这样：

<persistence-unit name="defaultPersistenceUnit" transaction-type="RESOURCE_LOCAL">
   <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
   <non-jta-data-source>DefaultDS</non-jta-data-source>
   <properties>
      <property name="hibernate.dialect" value="org.hibernate.dialect.MySQL8Dialect"/>
   </properties>
</persistence-unit>

数据库配置和库版本如下所示： jpa.default=defaultPersistenceUnit "org.hibernate" % "hibernate-entitymanager" % "5.4.24.Final", "mysql" % "mysql-connector-java" % "8.0.22",

如何才能让 UUID 与 VARCHAR 一起工作？有什么我想念的吗？

Answer 1

尝试使用以下定义：

import org.hibernate.annotations.Type;

@Entity
@Table(name = "users")
public class UserDO {
    @Id
    @GeneratedValue(generator = "uuid2")
    @GenericGenerator(name = "uuid2", strategy = "uuid2")
    @Column(name = "id", updatable = false, nullable = false, columnDefinition = "VARCHAR(36)")
    @Type(type = "uuid-char")
    private UUID id;

    // ...
}

您的方言 UUID 似乎默认映射到 uuid-binary basic type。

P.S。请注意，将 UUID PK 保存为字符串可能会导致性能问题，如 this article:

中所述

Aside from the 9x cost in size (36 vs. 4 bytes for an int), strings don’t sort as fast as numbers because they rely on collation rules.

Hibernate 无法将 UUID 插入 VARCHAR 列

Hibernate can't insert UUID to VARCHAR column

java

mysql

hibernate

playframework