java 在实体上使用 lomboks @Data 和 @Builder
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Using lomboks @Data and @Builder on entity
提问by Jan Galinski
I am using the following:
我正在使用以下内容：
@Entity
@Data
@Builder
@NoArgsConstructor(force = true)
public class User {
private String id;
private String firstName;
private String lastName;
}
what I want to achieve: for JPA usage, I need a POJO with noArgConstructor, getters/setters and equals/hashCode/toString.
我想要实现的目标：对于 JPA 使用，我需要一个带有 noArgConstructor、getter/setter 和 equals/hashCode/toString 的 POJO。
For instance creation (for example in tests) I want to use User.builder().build();
例如创建（例如在测试中）我想使用 User.builder().build();
Problem: it does not compile, there seems to be an issue with the NoArgConstructor vs. RequiredFieldsConstructor:
问题：它无法编译，NoArgConstructor 与 RequiredFieldsConstructor 似乎存在问题：
Error:(15, 1) java: constructor User in class x.y.z.User cannot be applied to given types;
required: no arguments
found: java.lang.String,java.lang.String,java.lang.String,java.lang.String,java.lang.String
reason: actual and formal argument lists differ in length
Update: The error occurs when I try to create a new entity via new... the builder() works.
更新：当我尝试通过new... builder() 工作创建新实体时发生错误。
What do I miss? Isn't it possible to use @Data, @Entity and @Builder at the same time?
我想念什么？不能同时使用@Data、@Entity 和@Builder 吗？
采纳答案by Jan Galinski
I will answer my own question by summerizing the comments.
我将通过总结评论来回答我自己的问题。
First of all, thanks to @RoelSpilker, you can use Builder and Data together on one Pojo if you explicitly provide AllArgs- and NoArgs- constructors:
首先，感谢@RoelSpilker，如果您明确提供 AllArgs- 和 NoArgs- 构造函数，您可以在一个 Pojo 上同时使用 Builder 和 Data：
@RequiredArgsConstructor
@NoArgsConstructor
@Data
@Builder
public class Person {...}
But: the builder created for this class will not know any inherited fields. For my use case (having some AbstractEntities) this renders the solution useless and I will stick with manual helpers/builders for now.
但是：为这个类创建的构建器不会知道任何继承的字段。对于我的用例（有一些 AbstractEntities），这使得解决方案毫无用处，我现在将坚持使用手动助手/构建器。
回答by ???
try this code with lombok version 1.16.18 over :
在 lombok 版本 1.16.18 上尝试此代码：
@Data
@NoArgsConstructor
@AllArgsConstructor
@Builder
@Entity
public class User {
private String id;
private String firstName;
private String lastName;
}
回答by Lubo
Beware of that data objects aren't entities! Simply put, there is problem with hashcode/equals (when it considers id fields) and also toString method with lazy loaded parts of entity. For reference you can check Vlad Mihalceas article.
当心数据对象不是实体！简而言之，hashcode/equals（当它考虑 id 字段时）和 toString 方法存在问题，并且实体的延迟加载部分。作为参考，您可以查看Vlad Mihalceas 文章。
You should:
你应该：
- exclude id fields from hashcode/equals
- exclude association fields which are not managed in given entity from hashcode/equals
- exclude all lazy loaded fields from toString method
- exclude fields possibly causing circular references from toString method
- 从 hashcode/equals 中排除 id 字段
- 从 hashcode/equals 中排除给定实体中未管理的关联字段
- 从 toString 方法中排除所有延迟加载的字段
- 排除可能导致 toString 方法循环引用的字段
For sure read at least something on topic of how does JPA do "dirty checking" before beeing confident that your handwritten or generated equals/hashcode method is ok.
在确信您的手写或生成的 equals/hashcode 方法没有问题之前，一定要至少阅读一些关于 JPA 如何进行“脏检查”的主题。
回答by Xendar
In the Lombok documentation it is written: Person.builder().name("Adam Savage").city("San Francisco").job("Mythbusters").job("Unchained Reaction").build();
在 Lombok 文档中它是这样写的：Person.builder().name("Adam Savage").city("San Francisco").job("Mythbusters").job("Unchained Reaction").build();
Do you use this syntax for your purpose? According to your description it's not the case, and could explain the error you get?
您是否出于您的目的使用此语法？根据您的描述，情况并非如此，能否解释您遇到的错误？
