Java 使用 JPA 和 Hibernate 时 @Size、@Length 和 @Column(length=value) 的区别
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Difference between @Size, @Length and @Column(length=value) when using JPA and Hibernate
提问by Chris311
What is the difference between the validation check of the following three fields?
以下三个字段的验证检查有什么区别？
@Entity
public class MyEntity {
@Column(name = "MY_FIELD_1", length=13)
private String myField1;
@Column(name = "MY_FIELD_2")
@Size(min = 13, max = 13)
private String myField2;
@Column(name = "MY_FIELD_3")
@Length(min = 13, max = 13)
private String myField3;
// getter & setter
}
I read that the first one has to do with DDL stuff. The second is for bean-validation. The third is for hibernate-validation.
我读到第一个与 DDL 相关。第二个是用于 bean 验证。第三个是用于休眠验证。
Is that correct? What I still don't understand is: When do I have to use which one? When does one of these annotations trigger?
那是对的吗？我仍然不明白的是：我什么时候必须使用哪一个？这些注释之一何时触发？
Edit: Think of the following situation: Given the requirement to develope an entity with a field of type string with length 13. Which of above mentioned methods would you choose? Or even better: Which questions do you have to ask yourself to find out which one suits your purposes?
编辑：考虑以下情况：假设需要开发一个长度为 13 的字符串类型字段的实体。您会选择上述哪种方法？或者甚至更好：您必须问自己哪些问题才能找出哪个问题适合您的目的？
采纳答案by Vlad Mihalcea
@Columnis a JPA annotation and thelengthattribute is used by the schema generation tool to set the associated SQL column length.@Sizeis a Bean Validation annotation that validates that the associated String has a value whose length is bounded by the minimum and maximum values.@Lengthis a Hibernate-specific annotation and has the same meaning as@Size
@Column是一个 JPA 注释，length模式生成工具使用该属性来设置关联的 SQL 列长度。@Size是一个 Bean Validation 注释，用于验证关联的 String 是否具有长度受最小值和最大值限制的值。@Length是一个 Hibernate 特定的注解，与@Size
So both 2.and 3.should validate the Stringlength using Bean Validation. I'd pick 2.because it's generic.
因此，无论2.并且3.应该验证String使用Bean验证长度。我会选择2.因为它是通用的。
