JPA批注和ConstraintViolationException

问题描述

这个问题一遍又一遍地被询问/提及，但是我找不到我做错了什么还是该问题是真实的":我有一个简单的Oracle表的实体类，其中有一个字段应该是唯一的.它在数据库中具有唯一的约束.在实体定义中，我添加了JPA批注-

This question is being asked/mentioned over and over but I could not find if I am doing something wrong or that the problem is "real":I have an entity class for a simple Oracle table in which there is one field that should be unique.It has a unique constraint in the DB.In the entity definition I added the JPA annotation -

@Entity
@Table(name = "tbl", uniqueConstraints = @UniqueConstraint(columnNames = "uni_field"))
public class MyTable implements Serializable {
...
@Column(name = "uni_field", unique = true)
@NotNull(message = "Field is required.")
    private String field;
...

我正在使用JBoss问题是，我总是会陷入休眠异常，如果我想知道约束违规，它将把我与JPA实现联系起来.有没有办法在这种情况下捕获持久性过期并提供用户友好的消息?如果不是，则@Column(name = "uni_field", unique = true)或uniqueConstraints = @UniqueConstraint(columnNames = "uni_field")有什么用?

I am using JBossThe problem is that I am always ending up in hibernate exception which tie me up to the JPA implementation if I want to know the constraint violation.Is there a way to catch a persistency expcetion in such case and provide a user friendly message?If not than what use is there in the @Column(name = "uni_field", unique = true) or uniqueConstraints = @UniqueConstraint(columnNames = "uni_field") ?

推荐答案

如果要显示注释中定义的必填字段"消息，则可以捕获如下异常:

If you want to show "Field is required" message as defined in your annotation, you could catch your exception like this:

catch(javax.validation.ConstraintViolationException cve){
  Set<ConstraintViolation<?>> cvs = cve.getConstraintViolations();
  String errMsg = "";
  for (ConstraintViolation<?> cv : cvs) {
    errMsg = cv.getMessage();
  }
}

作为参考，请检查 OpenJPA Bean验证入门

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