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
我喜欢Jakub Jirutka使用Spring表达式语言的想法。如果您不想添加另一个库/依赖项(假设您已经使用了Spring)，下面是他的想法的简化实现。
约束:
@Constraint(validatedBy=ExpressionAssertValidator.class)
@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
public @interface ExpressionAssert {
String message() default "expression must evaluate to true";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
String value();
}
验证器:
public class ExpressionAssertValidator implements ConstraintValidator<ExpressionAssert, Object> {
private Expression exp;
public void initialize(ExpressionAssert annotation) {
ExpressionParser parser = new SpelExpressionParser();
exp = parser.parseExpression(annotation.value());
}
public boolean isValid(Object value, ConstraintValidatorContext context) {
return exp.getValue(value, Boolean.class);
}
}
像这样应用:
@ExpressionAssert(value="pass == passVerify", message="passwords must be same")
public class MyBean {
@Size(min=6, max=50)
private String pass;
private String passVerify;
}
非常好的解决方案，布拉德豪斯。是否有办法将@Matches注释应用到多个字段?
编辑: 下面是我想出的解决方案来回答这个问题，我修改了约束以接受数组而不是单个值:
@Matches(fields={"password", "email"}, verifyFields={"confirmPassword", "confirmEmail"})
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;
}
注释的代码:
package springapp.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 "{springapp.util.constraints.matches}";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
String[] fields();
String[] verifyFields();
}
以及实现:
package springapp.util.constraints;
import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;
import org.apache.commons.beanutils.BeanUtils;
public class MatchesValidator implements ConstraintValidator<Matches, Object> {
private String[] fields;
private String[] verifyFields;
public void initialize(Matches constraintAnnotation) {
fields = constraintAnnotation.fields();
verifyFields = constraintAnnotation.verifyFields();
}
public boolean isValid(Object value, ConstraintValidatorContext context) {
boolean matches = true;
for (int i=0; i<fields.length; i++) {
Object fieldObj, verifyFieldObj;
try {
fieldObj = BeanUtils.getProperty(value, fields[i]);
verifyFieldObj = BeanUtils.getProperty(value, verifyFields[i]);
} catch (Exception e) {
//ignore
continue;
}
boolean neitherSet = (fieldObj == null) && (verifyFieldObj == null);
if (neitherSet) {
continue;
}
boolean tempMatches = (fieldObj != null) && fieldObj.equals(verifyFieldObj);
if (!tempMatches) {
addConstraintViolation(context, fields[i]+ " fields do not match", verifyFields[i]);
}
matches = matches?tempMatches:matches;
}
return matches;
}
private void addConstraintViolation(ConstraintValidatorContext context, String message, String field) {
context.disableDefaultConstraintViolation();
context.buildConstraintViolationWithTemplate(message).addNode(field).addConstraintViolation();
}
}
我在Nicko的解决方案中做了一个小的调整，这样就没有必要使用Apache Commons BeanUtils库，并将其替换为春季已经可用的解决方案，对于那些使用它的人来说，我可以更简单:
import org.springframework.beans.BeanWrapper;
import org.springframework.beans.PropertyAccessorFactory;
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 object, final ConstraintValidatorContext context) {
BeanWrapper beanWrapper = PropertyAccessorFactory.forBeanPropertyAccess(object);
final Object firstObj = beanWrapper.getPropertyValue(firstFieldName);
final Object secondObj = beanWrapper.getPropertyValue(secondFieldName);
boolean isValid = firstObj == null && secondObj == null || firstObj != null && firstObj.equals(secondObj);
if (!isValid) {
context.disableDefaultConstraintViolation();
context.buildConstraintViolationWithTemplate(context.getDefaultConstraintMessageTemplate())
.addPropertyNode(firstFieldName)
.addConstraintViolation();
}
return isValid;
}
}
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;
}
}
你们太棒了。真是惊人的想法。我最喜欢阿尔伯托芬和麦金的，所以我决定把他们的想法结合起来。并开发一些通用的解决方案，以满足所有情况。以下是我提出的解决方案。
@Documented
@Constraint(validatedBy = NotFalseValidator.class)
@Target({ElementType.METHOD, ElementType.FIELD,ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
public @interface NotFalse {
String message() default "NotFalse";
String[] messages();
String[] properties();
String[] verifiers();
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
}
public class NotFalseValidator implements ConstraintValidator<NotFalse, Object> {
private String[] properties;
private String[] messages;
private String[] verifiers;
@Override
public void initialize(NotFalse flag) {
properties = flag.properties();
messages = flag.messages();
verifiers = flag.verifiers();
}
@Override
public boolean isValid(Object bean, ConstraintValidatorContext cxt) {
if(bean == null) {
return true;
}
boolean valid = true;
BeanWrapper beanWrapper = PropertyAccessorFactory.forBeanPropertyAccess(bean);
for(int i = 0; i< properties.length; i++) {
Boolean verified = (Boolean) beanWrapper.getPropertyValue(verifiers[i]);
valid &= isValidProperty(verified,messages[i],properties[i],cxt);
}
return valid;
}
boolean isValidProperty(Boolean flag,String message, String property, ConstraintValidatorContext cxt) {
if(flag == null || flag) {
return true;
} else {
cxt.disableDefaultConstraintViolation();
cxt.buildConstraintViolationWithTemplate(message)
.addPropertyNode(property)
.addConstraintViolation();
return false;
}
}
}
@NotFalse(
messages = {"End Date Before Start Date" , "Start Date Before End Date" } ,
properties={"endDateTime" , "startDateTime"},
verifiers = {"validDateRange" , "validDateRange"})
public class SyncSessionDTO implements ControllableNode {
@NotEmpty @NotPastDate
private Date startDateTime;
@NotEmpty
private Date endDateTime;
public Date getStartDateTime() {
return startDateTime;
}
public void setStartDateTime(Date startDateTime) {
this.startDateTime = startDateTime;
}
public Date getEndDateTime() {
return endDateTime;
}
public void setEndDateTime(Date endDateTime) {
this.endDateTime = endDateTime;
}
public Boolean getValidDateRange(){
if(startDateTime != null && endDateTime != null) {
return startDateTime.getTime() <= endDateTime.getTime();
}
return null;
}
}
