在Hibernate Validator 4.x中是否有跨字段验证的实现(或第三方实现)?如果不是,实现跨字段验证器的最干净的方法是什么?

例如,如何使用API来验证两个bean属性是否相等(例如验证密码字段与密码验证字段是否匹配)。

在注释中,我期望如下内容:

public class MyBean {
  @Size(min=6, max=50)
  private String pass;

  @Equals(property="pass")
  private String passVerify;
}

当前回答

我没有评论第一个答案的名声,但我想补充的是,我已经为获胜的答案添加了单元测试,并有以下观察:

如果第一个或字段名出错,就会出现验证错误,就好像值不匹配一样。不要被拼写错误绊倒。

@FieldMatch(first=“invalidFieldName1”, second=“validFieldName2”)

验证器将接受等效的数据类型,即这些都将通过FieldMatch:

private String stringField = "1"; private Integer integerField = new Integer(1) private int intField = 1;

如果字段的对象类型没有实现equals,则验证将失败。

其他回答

每个字段约束都应该由不同的验证器注释处理,或者换句话说,不建议使用一个字段的验证注释检查其他字段;跨域验证应该在类级别进行。此外,JSR-303第2.2节表示同一类型的多个验证的首选方法是通过注释列表。这允许在每次匹配时指定错误消息。

例如,验证一个公共表单:

@FieldMatch.List({
        @FieldMatch(first = "password", second = "confirmPassword", message = "The password fields must match"),
        @FieldMatch(first = "email", second = "confirmEmail", message = "The email fields must match")
})
public class UserRegistrationForm  {
    @NotNull
    @Size(min=8, max=25)
    private String password;

    @NotNull
    @Size(min=8, max=25)
    private String confirmPassword;

    @NotNull
    @Email
    private String email;

    @NotNull
    @Email
    private String confirmEmail;
}

注释:

package constraints;

import constraints.impl.FieldMatchValidator;

import javax.validation.Constraint;
import javax.validation.Payload;
import java.lang.annotation.Documented;
import static java.lang.annotation.ElementType.ANNOTATION_TYPE;
import static java.lang.annotation.ElementType.TYPE;
import java.lang.annotation.Retention;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
import java.lang.annotation.Target;

/**
 * Validation annotation to validate that 2 fields have the same value.
 * An array of fields and their matching confirmation fields can be supplied.
 *
 * Example, compare 1 pair of fields:
 * @FieldMatch(first = "password", second = "confirmPassword", message = "The password fields must match")
 * 
 * Example, compare more than 1 pair of fields:
 * @FieldMatch.List({
 *   @FieldMatch(first = "password", second = "confirmPassword", message = "The password fields must match"),
 *   @FieldMatch(first = "email", second = "confirmEmail", message = "The email fields must match")})
 */
@Target({TYPE, ANNOTATION_TYPE})
@Retention(RUNTIME)
@Constraint(validatedBy = FieldMatchValidator.class)
@Documented
public @interface FieldMatch
{
    String message() default "{constraints.fieldmatch}";

    Class<?>[] groups() default {};

    Class<? extends Payload>[] payload() default {};

    /**
     * @return The first field
     */
    String first();

    /**
     * @return The second field
     */
    String second();

    /**
     * Defines several <code>@FieldMatch</code> annotations on the same element
     *
     * @see FieldMatch
     */
    @Target({TYPE, ANNOTATION_TYPE})
    @Retention(RUNTIME)
    @Documented
            @interface List
    {
        FieldMatch[] value();
    }
}

验证器:

package constraints.impl;

import constraints.FieldMatch;
import org.apache.commons.beanutils.BeanUtils;

import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;

public class FieldMatchValidator implements ConstraintValidator<FieldMatch, Object>
{
    private String firstFieldName;
    private String secondFieldName;

    @Override
    public void initialize(final FieldMatch constraintAnnotation)
    {
        firstFieldName = constraintAnnotation.first();
        secondFieldName = constraintAnnotation.second();
    }

    @Override
    public boolean isValid(final Object value, final ConstraintValidatorContext context)
    {
        try
        {
            final Object firstObj = BeanUtils.getProperty(value, firstFieldName);
            final Object secondObj = BeanUtils.getProperty(value, secondFieldName);

            return firstObj == null && secondObj == null || firstObj != null && firstObj.equals(secondObj);
        }
        catch (final Exception ignore)
        {
            // ignore
        }
        return true;
    }
}

我很惊讶这个没有开箱即用。不管怎样,这里有一个可能的解决方案。

我创建了一个类级验证器,而不是原始问题中描述的字段级验证器。

下面是注释代码:

package com.moa.podium.util.constraints;

import static java.lang.annotation.ElementType.*;
import static java.lang.annotation.RetentionPolicy.*;

import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;

import javax.validation.Constraint;
import javax.validation.Payload;

@Target({TYPE, ANNOTATION_TYPE})
@Retention(RUNTIME)
@Constraint(validatedBy = MatchesValidator.class)
@Documented
public @interface Matches {

  String message() default "{com.moa.podium.util.constraints.matches}";

  Class<?>[] groups() default {};

  Class<? extends Payload>[] payload() default {};

  String field();

  String verifyField();
}

以及验证器本身:

package com.moa.podium.util.constraints;

import org.mvel2.MVEL;

import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;

public class MatchesValidator implements ConstraintValidator<Matches, Object> {

  private String field;
  private String verifyField;


  public void initialize(Matches constraintAnnotation) {
    this.field = constraintAnnotation.field();
    this.verifyField = constraintAnnotation.verifyField();
  }

  public boolean isValid(Object value, ConstraintValidatorContext context) {
    Object fieldObj = MVEL.getProperty(field, value);
    Object verifyFieldObj = MVEL.getProperty(verifyField, value);

    boolean neitherSet = (fieldObj == null) && (verifyFieldObj == null);

    if (neitherSet) {
      return true;
    }

    boolean matches = (fieldObj != null) && fieldObj.equals(verifyFieldObj);

    if (!matches) {
      context.disableDefaultConstraintViolation();
      context.buildConstraintViolationWithTemplate("message")
          .addNode(verifyField)
          .addConstraintViolation();
    }

    return matches;
  }
}

注意,我已经使用MVEL来检查正在验证的对象的属性。这可以用标准反射api代替,或者如果它是您正在验证的特定类,则使用访问器方法本身。

@Matches注释可以像下面这样使用在bean上:

@Matches(field="pass", verifyField="passRepeat")
public class AccountCreateForm {

  @Size(min=6, max=50)
  private String pass;
  private String passRepeat;

  ...
}

作为免责声明,我在最后5分钟写了这篇文章,所以我可能还没有解决所有的错误。如果有任何错误,我将更新答案。

如果您正在使用Spring框架,那么您可以使用Spring表达式语言(SpEL)。我写了一个小库,提供了基于SpEL的JSR-303验证器——它使得跨领域验证变得轻而易举!看看https://github.com/jirutka/validator-spring。

这将验证密码字段的长度和相等性。

@SpELAssert(value = "pass.equals(passVerify)",
            message = "{validator.passwords_not_same}")
public class MyBean {

    @Size(min = 6, max = 50)
    private String pass;

    private String passVerify;
}

您还可以轻松地进行修改,仅当密码字段不为空时才验证密码字段。

@SpELAssert(value = "pass.equals(passVerify)",
            applyIf = "pass || passVerify",
            message = "{validator.passwords_not_same}")
public class MyBean {

    @Size(min = 6, max = 50)
    private String pass;

    private String passVerify;
}

我尝试了Alberthoven的例子(hibernate-validator 4.0.2.GA),我得到了一个ValidationException:“带注释的方法必须遵循JavaBeans命名约定。Match()没有。”。在我将方法从“match”重命名为“isValid”后,它就工作了。

public class Password {

    private String password;

    private String retypedPassword;

    public Password(String password, String retypedPassword) {
        super();
        this.password = password;
        this.retypedPassword = retypedPassword;
    }

    @AssertTrue(message="password should match retyped password")
    private boolean isValid(){
        if (password == null) {
            return retypedPassword == null;
        } else {
            return password.equals(retypedPassword);
        }
    }

    public String getPassword() {
        return password;
    }

    public String getRetypedPassword() {
        return retypedPassword;
    }

}

我建议你另一种可能的解决办法。也许不那么优雅,但更容易!

public class MyBean {
  @Size(min=6, max=50)
  private String pass;

  private String passVerify;

  @NotNull
  private LocalDate passExpiry;
  @NotNull
  private LocalDate dateOfJoining;

  @AssertTrue(message = "Fields `pass` and `passVerify` should be equal")
  // Any method name is ok als long it begins with `is`
  private boolean isValidPass() {
    //return pass == null && passVerify == null || pass.equals(passVerify);
    // Since Java 7:
    return Objects.equals(pass, passVerify);
  }

  @AssertTrue(message = "Field `passExpiry` should be later than `dateOfJoining`")
  // Other rules can also be validated in other methods
  private boolean isPassExpiryAfterDateOfJoining() {
    return dateOfJoining.isBefore(passExpiry);
  }
}

isValid()和isPassExpiryAfterDateOfJoining()方法由验证器自动调用。在ConstraintViolations中报告的属性路径将从方法名中提取:valid和passExpiryAfterDateOfJoining。