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
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").
其他回答
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;
}
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;
}
}
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").
