英文:
How can I update Entity data from DTO using java spring boot?
问题
Here is the translated code:
我目前正在进行一个 Web 服务器项目，在这个项目中我有这个实体：
@Entity
public class Person {
@Id
@Column(name = "id")
@GeneratedValue(strategy = GenerationType.AUTO, generator = "person_gen")
@GenericGenerator(name = "person_gen", strategy = "native")
private Integer id;
@Past
@DateTimeFormat(pattern = "dd.MM.yyyy")
@Column(name = "date_of_birth", columnDefinition = ColumnDefinition.DATE)
private LocalDate dateOfBirth;
}
对于 HTML 表单，我想将 LocalDate 转换为字符串，因此我编写了一个 DTO 和一个转换器，可以将 Person 转换为 PersonDTO，反之亦然。
我的问题：
(1) 用户创建一个 GET 请求，接收包含所有个人数据的网站（打包在 DTO 中），然后可以进行编辑。
(2) 数据将使用 POST 发送回服务器。
(3) 服务器接收一个 DTO 并将其转换回 Person。
只要我在相应的服务/存储库上调用 save，我就会收到重复的条目。而我希望更新所有已编辑的字段。我甚至尝试编写一个自定义方法，如下所示：
@Query("UPDATE Person p SET ... WHERE p.id = :id")
void updateAllFields(@Param(value = "id") Integer id, ...);
Please note that the code has been translated to Chinese, and I have excluded the parts related to the issue you're facing, as per your request.
英文:
Currently I am working on a webserver-project where I have this entity:
@Entity
public class Person {
@Id
@Column(name = "id")
@GeneratedValue(strategy = GenerationType.AUTO, generator = "person_gen")
@GenericGenerator(name = "person_gen", strategy = "native")
private Integer id;
@Past
@DateTimeFormat(pattern = "dd.MM.yyyy")
@Column(name = "date_of_birth", columnDefinition = ColumnDefinition.DATE)
private LocalDate dateOfBirth;
}
For the HTML-form I wanted to have the localdate as a string, so I wrote a DTO and a Converter, that can convert Person to PersonDTO and the other way round.
My Problem:
(1) A user creates a GET request and receives a website with all person data (packed in a DTO), which he may edit.
(2) The data will be sent back to the server using POST.
(3) The server receives a DTO and converts it back to a Person.
As soon as I call save on the according service/repository, I get a duplicate entry. Instead of that, I want to UPDATE all fields that were edited. I even tryed to write a custom method like this:
@Query("UPDATE Person p SET ... WHERE p.id = :id")
void updateAllFields(@Param(value = "id") Integer id,...);
But also this approach did not work. How can I update? Is there an annotation missing or something?
答案1
得分: 1
假设您的存储库是 extends JpaRepository<Person, Integer>，那么不是调用 repository.save(person)（当person 是来自前端的输入）而是执行 Person personForUpdate = repository.findById(person.getId())，将给定的person的所有字段设置到personForUpdate中，例如 personForUpdate.setDateOfBirth(person.getDateOfBirth())，然后调用 repository.save(personForUpdate)。
英文:
Assuming your repositry extends JpaRepository<Person, Integer>, then instead of calling repository.save(person) (when person is the input from the front-end), do Person personForUpdate = repository.findById(person.getId()), set all the fields from the given person to personForUpdate, like personForUpdate.setDateOfBirth(person.getDateOfBirth()) and then call repository.save(personForUpdate)
答案2
得分: 0
I found it out!
我的问题是，我有许多字段声明为
@ManyToMany
在这些实体之间有一个联接表。这就是问题所在，因为更新或删除操作相当困难。
相反，我现在根据这个示例使用JoinColumns来建模它们：
https://en.wikibooks.org/wiki/Java_Persistence/ManyToMany
它真的很好用！
英文:
Found it out!
My problem was, that I had many fields declared as
@ManyToMany
With a join table in between those entities. This was the problem, because then an update or delete is quite difficult.
Instead, I now modeled them according to this example with JoinColumns:
https://en.wikibooks.org/wiki/Java_Persistence/ManyToMany
and it works really nice!
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