如何验证数据库中用户名的可用性？

How can I validate the entered username in an input text field if it is available according to the database? I am using JSF2.

如果根据数据库可用,在输入文本字段中如何验证输入的用户名?我正在使用JSF2。

1 个解决方案

#1

Just implement a Validator yourself.

只需自己实现验证器。

@ManagedBean
@RequestScoped
public class UserNameAvailableValidator implements Validator {

    @EJB
    private UserService userService;

    @Override
    public void validate(FacesContext context, UIComponent component, Object value) throws ValidatorException {
        String userName = (String) value;

        if (!userService.isUsernameAvailable(userName)) {
            throw new ValidatorException(new FacesMessage("Username not avaliable"));
        }
    }

}

(please note that it's a @ManagedBean instead of @FacesValidator because of the need to inject an @EJB; if you're not using EJBs, you can make it a @FacesValidator instead)

(请注意,它是@ManagedBean而不是@FacesValidator,因为需要注入@EJB;如果你不使用EJB,你可以改为使用@FacesValidator)

Use it as follows:

使用方法如下:

<h:inputText id="username" value="#{register.user.name}" required="true">
    <f:validator binding="#{userNameAvailableValidator}" />
    <f:ajax event="blur" render="username_message" />
</h:inputText>
<h:message id="username_message" for="username" />

#1