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
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;
}
}
其他回答
使用Hibernate Validator 4.1.0。最后，我建议使用@ScriptAssert。除了它的JavaDoc:
脚本表达式可以用任何脚本或表达式编写 JSR 223(“java平台脚本编写”) 兼容的引擎可以在类路径中找到。
注意:评估是由运行在Java VM中的脚本“引擎”执行的，因此是在Java“服务器端”，而不是在某些注释中所述的“客户端”。
例子:
@ScriptAssert(lang = "javascript", script = "_this.passVerify.equals(_this.pass)")
public class MyBean {
@Size(min=6, max=50)
private String pass;
private String passVerify;
}
或者使用更短的别名和null安全:
@ScriptAssert(lang = "javascript", alias = "_",
script = "_.passVerify != null && _.passVerify.equals(_.pass)")
public class MyBean {
@Size(min=6, max=50)
private String pass;
private String passVerify;
}
或者使用Java 7+ null-safe Objects.equals():
@ScriptAssert(lang = "javascript", script = "Objects.equals(_this.passVerify, _this.pass)")
public class MyBean {
@Size(min=6, max=50)
private String pass;
private String passVerify;
}
尽管如此，自定义类级验证器@Matches解决方案并没有什么问题。
为什么不试试Oval: http://oval.sourceforge.net/呢
我看起来像它支持OGNL，所以也许你可以用更自然的方式来做
@Assert(expr = "_value ==_this.pass").
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;
}
}
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;
}
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;
}
}
