Java 验证Spring中的Jstl等于字符串

我正在使用属性发出多语言错误警报以进行验证（注释和Spring） 我想检查一下它的大小 但即使我使用

<c:set var="checkusername"><form:errors path="username"/></c:set>
<c:if test="${checkusername == 'username.id'}">
   div class="loi"><s:message code="global.check.username"/></div>
</c:if>
<c:if test="${checkusername == 'username.length'}">
   div class="loi"><s:message code="global.check.usernamelength"/></div>
</c:if>

我的模型用户：

@Entity
@Table(name = "Users")
public class User  {

    @Id
    @Column(name = "username")
    @NotBlank(message = "username.id")
    @Size(min=0,max=50,message="username.length")
    private String username;

    @Column(name = "password")
    @NotBlank(message = "Không được để trống mật khẩu")
    private String password;

    @Column(name = "fullname")
    @NotBlank(message = "Không được để trống họ tên")
    private String fullname;

    public User() {

    }

    public User(String username, String password) {
        this.username = username;
        this.password = password;
    }

    public User(String username, String password, String fullname) {
        this.username = username;
        this.password = password;
        this.fullname = fullname;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getFullname() {
        return fullname;
    }

    public void setFullname(String fullname) {
        this.fullname = fullname;
    }

---

您可以使用bean验证显示多语言环境错误消息

您需要很少的配置来实现这一点

@Bean(name = "messageSource")
public ReloadableResourceBundleMessageSource validationMessageSource() {
    ReloadableResourceBundleMessageSource messageSource = new ReloadableResourceBundleMessageSource();
    messageSource.setBasename("classpath:global");
    ...
    return messageSource;
}

这将从相应的语言环境文件中获取错误消息

@Bean
public LocaleResolver localeResolver(){
    SessionLocaleResolver r = new SessionLocaleResolver();
    r.setDefaultLocale(Locale.US);
    return r;
}

需要将我们的

LocaleResolver

注册为bean

@Override
public void addInterceptors (InterceptorRegistry registry) {
    LocaleChangeInterceptor l = new LocaleChangeInterceptor();
    l.setParamName("localeCode");
    registry.addInterceptor(l);
}

仅当HTTP请求中存在指定的请求参数（由

LocaleChangeInterceptor.setParamName（..）

设置）时，此侦听器才能在每个请求上更改基础

LocaleResolver

的当前区域设置

及

@Bean
public LocaleResolver localeResolver(){
    SessionLocaleResolver r = new SessionLocaleResolver();
    r.setDefaultLocale(Locale.US);
    return r;
}

@Override
public void addInterceptors (InterceptorRegistry registry) {
    LocaleChangeInterceptor l = new LocaleChangeInterceptor();
    l.setParamName("localeCode");
    registry.addInterceptor(l);
}

...
@NotBlank(message = "{global.check.username}")
@Size(min=0,max=50,message="{global.check.usernamelength}")
private String username;

@NotBlank(message = "{global.check.username}")
private String password;
...