JSR 303 验证，如果一个字段等于“某物”，则这些其他字段不应为空

Question

我希望使用 JSR-303 javax.validation 进行一些自定义验证。

我有一个领域。如果在这个字段中输入了某个值，我想要求其他几个字段不是null。

我正在努力解决这个问题。不确定我会称之为什么来帮助找到解释。

任何帮助将不胜感激。我对此很陌生。

目前我正在考虑自定义约束。但我不确定如何从注释中测试依赖字段的值。基本上我不确定如何从注释中访问面板对象。

public class StatusValidator implements ConstraintValidator<NotNull, String> {

    @Override
    public void initialize(NotNull constraintAnnotation) {}

    @Override
    public boolean isValid(String value, ConstraintValidatorContext context) {
        if ("Canceled".equals(panel.status.getValue())) {
            if (value != null) {
                return true;
            }
        } else {
            return false;
        }
    }
}

这是panel.status.getValue(); 给我带来了麻烦.. 不知道如何做到这一点。

Answer 1

示例如下：

package io.quee.sample.javax;

import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

import javax.validation.ConstraintViolation;
import javax.validation.Valid;
import javax.validation.Validator;
import javax.validation.constraints.Pattern;
import java.util.Set;

/**
 * Created By [**Ibrahim Al-Tamimi **](https://www.linkedin.com/in/iloom/)
 * Created At **Wednesday **23**, September 2020**
 */
@SpringBootApplication
public class SampleJavaXValidation implements CommandLineRunner {
    private final Validator validator;

    public SampleJavaXValidation(Validator validator) {
        this.validator = validator;
    }

    public static void main(String[] args) {
        SpringApplication.run(SampleJavaXValidation.class, args);
    }

    @Override
    public void run(String... args) throws Exception {
        Set<ConstraintViolation<SampleDataCls>> validate = validator.validate(new SampleDataCls(SampleTypes.TYPE_A, null, null));
        System.out.println(validate);
    }

    public enum SampleTypes {
        TYPE_A,
        TYPE_B;
    }

    @Valid
    public static class SampleDataCls {
        private final SampleTypes type;
        private final String valueA;
        private final String valueB;

        public SampleDataCls(SampleTypes type, String valueA, String valueB) {
            this.type = type;
            this.valueA = valueA;
            this.valueB = valueB;
        }

        public SampleTypes getType() {
            return type;
        }

        public String getValueA() {
            return valueA;
        }

        public String getValueB() {
            return valueB;
        }

        @Pattern(regexp = "TRUE")
        public String getConditionalValueA() {
            if (type.equals(SampleTypes.TYPE_A)) {
                return valueA != null ? "TRUE" : "";
            }
            return "TRUE";
        }

        @Pattern(regexp = "TRUE")
        public String getConditionalValueB() {
            if (type.equals(SampleTypes.TYPE_B)) {
                return valueB != null ? "TRUE" : "";
            }
            return "TRUE";
        }
    }
}

Answer 2

在这种情况下，我建议编写一个自定义验证器，它将在类级别验证（以允许我们访问对象的字段）只有当另一个字段具有特定值时才需要一个字段。请注意，您应该编写获取 2 个字段名称并仅使用这 2 个字段的通用验证器。要要求多个字段，您应该为每个字段添加此验证器。

使用下面的代码作为一个想法（我没有测试过）。

• 验证器接口

  /**
   * Validates that field {@code dependFieldName} is not null if
   * field {@code fieldName} has value {@code fieldValue}.
   **/
  @Target({TYPE, ANNOTATION_TYPE})
  @Retention(RUNTIME)
  @Repeatable(NotNullIfAnotherFieldHasValue.List.class) // only with hibernate-validator >= 6.x
  @Constraint(validatedBy = NotNullIfAnotherFieldHasValueValidator.class)
  @Documented
  public @interface NotNullIfAnotherFieldHasValue {
  
      String fieldName();
      String fieldValue();
      String dependFieldName();
  
      String message() default "{NotNullIfAnotherFieldHasValue.message}";
      Class<?>[] groups() default {};
      Class<? extends Payload>[] payload() default {};
  
      @Target({TYPE, ANNOTATION_TYPE})
      @Retention(RUNTIME)
      @Documented
      @interface List {
          NotNullIfAnotherFieldHasValue[] value();
      }
  
  }
  

• 验证器实现

  /**
   * Implementation of {@link NotNullIfAnotherFieldHasValue} validator.
   **/
  public class NotNullIfAnotherFieldHasValueValidator
      implements ConstraintValidator<NotNullIfAnotherFieldHasValue, Object> {
  
      private String fieldName;
      private String expectedFieldValue;
      private String dependFieldName;
  
      @Override
      public void initialize(NotNullIfAnotherFieldHasValue annotation) {
          fieldName          = annotation.fieldName();
          expectedFieldValue = annotation.fieldValue();
          dependFieldName    = annotation.dependFieldName();
      }
  
      @Override
      public boolean isValid(Object value, ConstraintValidatorContext ctx) {
  
          if (value == null) {
              return true;
          }
  
          try {
              String fieldValue       = BeanUtils.getProperty(value, fieldName);
              String dependFieldValue = BeanUtils.getProperty(value, dependFieldName);
  
              if (expectedFieldValue.equals(fieldValue) && dependFieldValue == null) {
                  ctx.disableDefaultConstraintViolation();
                  ctx.buildConstraintViolationWithTemplate(ctx.getDefaultConstraintMessageTemplate())
                      .addNode(dependFieldName)
                      .addConstraintViolation();
                      return false;
              }
  
          } catch (NoSuchMethodException | InvocationTargetException | IllegalAccessException ex) {
              throw new RuntimeException(ex);
          }
  
          return true;
      }
  
  }
  

• 验证器使用示例（hibernate-validator >= 6 with Java 8+）

  @NotNullIfAnotherFieldHasValue(
      fieldName = "status",
      fieldValue = "Canceled",
      dependFieldName = "fieldOne")
  @NotNullIfAnotherFieldHasValue(
      fieldName = "status",
      fieldValue = "Canceled",
      dependFieldName = "fieldTwo")
  public class SampleBean {
      private String status;
      private String fieldOne;
      private String fieldTwo;
  
      // getters and setters omitted
  }
  

• 验证器使用示例（hibernate-validator

  @NotNullIfAnotherFieldHasValue.List({
      @NotNullIfAnotherFieldHasValue(
          fieldName = "status",
          fieldValue = "Canceled",
          dependFieldName = "fieldOne"),
      @NotNullIfAnotherFieldHasValue(
          fieldName = "status",
          fieldValue = "Canceled",
          dependFieldName = "fieldTwo")
  })
  public class SampleBean {
      private String status;
      private String fieldOne;
      private String fieldTwo;
  
      // getters and setters omitted
  }
  

请注意，验证器实现使用 commons-beanutils 库中的 BeanUtils 类，但您也可以使用 BeanWrapperImpl from Spring Framework。

另请参阅这个很棒的答案：Cross field validation with Hibernate Validator (JSR 303)

Answer 3

这是我的看法，尽量保持简单。

界面：

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

    String message() default "{one.of.message}";

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

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

    String[] value();
}

验证实现：

public class OneOfValidator implements ConstraintValidator<OneOf, Object> {

    private String[] fields;

    @Override
    public void initialize(OneOf annotation) {
        this.fields = annotation.value();
    }

    @Override
    public boolean isValid(Object value, ConstraintValidatorContext context) {

        BeanWrapper wrapper = PropertyAccessorFactory.forBeanPropertyAccess(value);

        int matches = countNumberOfMatches(wrapper);

        if (matches > 1) {
            setValidationErrorMessage(context, "one.of.too.many.matches.message");
            return false;
        } else if (matches == 0) {
            setValidationErrorMessage(context, "one.of.no.matches.message");
            return false;
        }

        return true;
    }

    private int countNumberOfMatches(BeanWrapper wrapper) {
        int matches = 0;
        for (String field : fields) {
            Object value = wrapper.getPropertyValue(field);
            boolean isPresent = detectOptionalValue(value);

            if (value != null && isPresent) {
                matches++;
            }
        }
        return matches;
    }

    private boolean detectOptionalValue(Object value) {
        if (value instanceof Optional) {
            return ((Optional) value).isPresent();
        }
        return true;
    }

    private void setValidationErrorMessage(ConstraintValidatorContext context, String template) {
        context.disableDefaultConstraintViolation();
        context
            .buildConstraintViolationWithTemplate("{" + template + "}")
            .addConstraintViolation();
    }

}

用法：

@OneOf({"stateType", "modeType"})
public class OneOfValidatorTestClass {

    private StateType stateType;

    private ModeType modeType;

}

消息：

one.of.too.many.matches.message=Only one of the following fields can be specified: {value}
one.of.no.matches.message=Exactly one of the following fields must be specified: {value}

Answer 4

定义必须验证为真的方法并将@AssertTrue注解放在其顶部：

  @AssertTrue
  private boolean isOk() {
    return someField != something || otherField != null;
  }

方法必须以'is'开头。

Answer 5

你应该使用自定义DefaultGroupSequenceProvider<T>:

ConditionalValidation.java

// Marker interface
public interface ConditionalValidation {}

MyCustomFormSequenceProvider.java

public class MyCustomFormSequenceProvider
    implements DefaultGroupSequenceProvider<MyCustomForm> {

    @Override
    public List<Class<?>> getValidationGroups(MyCustomForm myCustomForm) {

        List<Class<?>> sequence = new ArrayList<>();

        // Apply all validation rules from ConditionalValidation group
        // only if someField has given value
        if ("some value".equals(myCustomForm.getSomeField())) {
            sequence.add(ConditionalValidation.class);
        }

        // Apply all validation rules from default group
        sequence.add(MyCustomForm.class);

        return sequence;
    }
}

MyCustomForm.java

@GroupSequenceProvider(MyCustomFormSequenceProvider.class)
public class MyCustomForm {

    private String someField;

    @NotEmpty(groups = ConditionalValidation.class)
    private String fieldTwo;

    @NotEmpty(groups = ConditionalValidation.class)
    private String fieldThree;

    @NotEmpty
    private String fieldAlwaysValidated;


    // getters, setters omitted
}

另见related question on this topic。

Answer 6

另一种方法是创建一个（受保护的）getter，它返回一个包含所有相关字段的对象。示例：

public class MyBean {
  protected String status;
  protected String name;

  @StatusAndSomethingValidator
  protected StatusAndSomething getStatusAndName() {
    return new StatusAndSomething(status,name);
  }
}

StatusAndSomethingValidator 现在可以访问 StatusAndSomething.status 和 StatusAndSomething.something 并进行相关检查。