Thymeleaf 和@Uniqueconstraint [英] Thymeleaf and @Uniqueconstraint

问题描述

我想问一下如何处理 thymeleaf 的 uniquecontraint 异常.为了处理异常，我正在使用它:

I want to ask how to handle uniquecontraint exception at thymeleaf. To handle excpetion I am using this:

<span th:style="'color:red'" th:if="${#fields.hasErrors('userName')}" th:errors="*{userName}">Name Error</span>

它处理 lenght 异常而不是 null，但为什么它会因 uniqe 约束而失败，我的实体看起来像这样:

It handles lenght exception and not null, but why it fail with uniqe constraint, my entity looks like this:

@Entity(name = "Users")
@Table(
        name = "\"users\"",
        uniqueConstraints = {
                @UniqueConstraint( name = "users_username_unique", columnNames = "user_name")
        }
)
public class Users {

...

    @Column(
            name = "user_name",
            nullable = false,
            columnDefinition = "TEXT",
            updatable = false
    )
    @Length(min = 5, message = "*User name is too short")
    @NotEmpty(message = "*Enter user name")
    private String userName;

...
}

推荐答案

唯一列只会在DDL生成时使用，在运行时不会有任何影响. 实际的唯一性检查发生在数据库中.

Unique columns will be used only in DDL generation, it doesn't have any impact during runtime. The actual uniqueness checks happens in the database.

我可以建议您这样做的方法.方法是检查这个用户名是否可用，你可以相应地出错，例如，它可能是这样的代码:

I can suggest method for you to do this. The method is to check if this username is available and you can make an error accordingly, s an example, it could be a code like this:

Optional<Users> optionalUser = userRepository.findByUserName(..);
if(optionalUser.isPresent()){
    bindingResult.rejectValue("userName", "error.userName", "You cannot use this username!");
    return "form";
}

有关 BindingResult 类和 rejectValue() 方法的更多信息，请参见此处:https://stackoverflow.com/a/65759773/2039546

More information about the BindingResult class and the rejectValue() method, see here: https://stackoverflow.com/a/65759773/2039546

OR

其他可能的解决方案是创建自定义注释和验证器，请参见此处:https://stackoverflow.com/a/4733441/2039546

Other of the possible solutions is to create custom annotation and validator, see here: https://stackoverflow.com/a/4733441/2039546

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