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java-Hibernate无法将UUID插入VARCHAR列

(java - Hibernate can't insert UUID to VARCHAR column)

发布于 2020-11-30 12:27:14

我正在建立一个MySQL数据库,并在后端使用Hibernate和Play Framework。我在输入ID时遇到问题。我将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,@Entity该类是这样的:

@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;
}

进行插入时,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BINARY(16)为insert可以使用,但是这样做的缺点是,在进行选择时ID是不可读的。

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",

可以做什么UUID工作VARCHAR有什么我想念的吗?

Questioner
Petre Popescu
Viewed
0
SternK 2020-12-04 04:22:54

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;

    // ...
}

UUID默认情况下,你的方言看起来就像映射到uuid-binary 基本类型

PS请注意,将UUIDPK保存为字符串会导致性能问题,如本文所述

除了大小的9倍成本(一个int的大小为36比4字节)之外,字符串的排序速度也不如数字快,因为它们依赖排序规则。