Hibernate 尝试在 CrudRepository 中插入 null id

Question

我正在使用内存 H2 数据库对 Spring 应用程序进行一些测试。数据库有一个“消息”表，其架构为：

CREATE TABLE `message` (
  `id` bigint(20) NOT NULL,
  `body` CLOB,
  `channels` varchar(500) NOT NULL,
  `end_date` datetime DEFAULT NULL,
  `start` datetime DEFAULT NULL,
  `status` varchar(120) DEFAULT NULL,
  `title` varchar(120) DEFAULT NULL,
  `approved` bit(1) DEFAULT NULL,
  `approver_name` varchar(150) DEFAULT NULL,
  `approver_sub` varchar(120) DEFAULT NULL,
  `create_date` datetime DEFAULT NULL,
  `creator_name` varchar(150) DEFAULT NULL,
  `creator_sub` varchar(120) DEFAULT NULL,
  `modify_date` datetime DEFAULT NULL,
  `affiliations` varchar(500) NOT NULL,
  `html` bit(1) NOT NULL,
  `reject_reason` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`id`)
)

和一个实体类：

@Entity
public class Message {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "id", length = 100, nullable = false, unique = true)
    private long id;

    @Column(name = "title", length = 120, nullable = true)
    private String title;

    @Lob
    @Column(name = "body", nullable = true)
    private String body;
...
}

在我的代码中，我尝试将新条目插入消息表中。我有一个服务方法，例如：

public Message saveMessage(MessageInput messageInput, LocalDateTime start, LocalDateTime end, String status, String requestor) {
        Message message = new Message();
        message.setTitle(messageInput.getMessage_title());
        message.setBody(messageInput.getMessage_body());
        messageRepository.save(message);
} 

其中 messageRepository 是 org.springframework.data.repository.CrudRepository

我打开了日志记录，当我运行代码时，我收到以下日志消息：

Hibernate: insert into message (id, affiliations, approved, approver_name, approver_sub, body, channels, create_date, creator_name, creator_sub, end_date, html, modify_date, reject_reason, start, status, title) values (default, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
2023-08-31 12:30:03 [main] TRACE o.h.type.descriptor.sql.BasicBinder - binding parameter [1] as [VARCHAR] - [[Employee, Staff]]
2023-08-31 12:30:03 [main] TRACE o.h.type.descriptor.sql.BasicBinder - binding parameter [2] as [BOOLEAN] - [false]
2023-08-31 12:30:03 [main] TRACE o.h.type.descriptor.sql.BasicBinder - binding parameter [3] as [VARCHAR] - [null]
2023-08-31 12:30:03 [main] TRACE o.h.type.descriptor.sql.BasicBinder - binding parameter [4] as [VARCHAR] - [null]
2023-08-31 12:30:03 [main] TRACE o.h.type.descriptor.sql.BasicBinder - binding parameter [5] as [CLOB] - [the test body]
2023-08-31 12:30:03 [main] TRACE o.h.type.descriptor.sql.BasicBinder - binding parameter [6] as [VARCHAR] - [[57823ff6-e262-4201-8766-84cd17dfe116]]
2023-08-31 12:30:03 [main] TRACE o.h.type.descriptor.sql.BasicBinder - binding parameter [7] as [TIMESTAMP] - [2023-08-31T12:30:03.304774]
2023-08-31 12:30:03 [main] TRACE o.h.type.descriptor.sql.BasicBinder - binding parameter [8] as [VARCHAR] - [ptb014]
2023-08-31 12:30:03 [main] TRACE o.h.type.descriptor.sql.BasicBinder - binding parameter [9] as [VARCHAR] - [ptb014]
2023-08-31 12:30:03 [main] TRACE o.h.type.descriptor.sql.BasicBinder - binding parameter [10] as [TIMESTAMP] - [2023-09-07T12:30:03.268680]
2023-08-31 12:30:03 [main] TRACE o.h.type.descriptor.sql.BasicBinder - binding parameter [11] as [BOOLEAN] - [false]
2023-08-31 12:30:03 [main] TRACE o.h.type.descriptor.sql.BasicBinder - binding parameter [12] as [TIMESTAMP] - [2023-08-31T12:30:03.304793]
2023-08-31 12:30:03 [main] TRACE o.h.type.descriptor.sql.BasicBinder - binding parameter [13] as [VARCHAR] - [null]
2023-08-31 12:30:03 [main] TRACE o.h.type.descriptor.sql.BasicBinder - binding parameter [14] as [TIMESTAMP] - [2023-08-31T12:30:03.268680]
2023-08-31 12:30:03 [main] TRACE o.h.type.descriptor.sql.BasicBinder - binding parameter [15] as [VARCHAR] - [MODERATOR_APPROVED]
2023-08-31 12:30:03 [main] TRACE o.h.type.descriptor.sql.BasicBinder - binding parameter [16] as [VARCHAR] - [A Title]
2023-08-31 12:30:03 [main] ERROR o.h.e.jdbc.spi.SqlExceptionHelper - NULL not allowed for column "ID"; SQL statement:
insert into message (id, affiliations, approved, approver_name, approver_sub, body, channels, create_date, creator_name, creator_sub, end_date, html, modify_date, reject_reason, start, status, title) values (default, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?) [23502-220]

查看日志，似乎插入包含一个 id 参数，但由于数据库期望生成该值，因此它被传递为 NULL。我做了一些研究，我看到的大多数建议都建议将 GenerationType 设置为 IDENTITY 或将 spring.jpa.hibernate.ddl-auto 配置更改为“更新”。我都尝试了，但仍然得到相同的结果。我需要做什么才能让身份生成发挥作用？

Answer 1

您需要将

id

列声明为标识列：

id BIGINT GENERATED BY DEFAULT AS IDENTITY

在H2的MySQL或MariaDB兼容模式中可以使用非标准

`id` BIGINT AUTO_INCREMENT

相反。