程序包 cn.taketoday.validation

接口 Validator

所有已知子接口:

SmartValidator

所有已知实现类:

CustomValidatorBean, InfraValidatorAdapter, LocalValidatorFactoryBean, OptionalValidatorFactoryBean

public interface Validator

A validator for application-specific objects.

This interface is totally divorced from any infrastructure or context; that is to say it is not coupled to validating only objects in the web tier, the data-access tier, or the whatever-tier. As such it is amenable to being used in any layer of an application, and supports the encapsulation of validation logic as a first-class citizen in its own right.

Find below a simple but complete Validator implementation, which validates that the various String properties of a UserLogin instance are not empty (that is they are not null and do not consist wholly of whitespace), and that any password that is present is at least 'MINIMUM_PASSWORD_LENGTH' characters in length.

public class UserLoginValidator implements Validator {

    private static final int MINIMUM_PASSWORD_LENGTH = 6;

    public boolean supports(Class clazz) {
       return UserLogin.class.isAssignableFrom(clazz);
    }

    public void validate(Object target, Errors errors) {
       ValidationUtils.rejectIfEmptyOrWhitespace(errors, "userName", "field.required");
       ValidationUtils.rejectIfEmptyOrWhitespace(errors, "password", "field.required");
       UserLogin login = (UserLogin) target;
       if (login.getPassword() != null
             && login.getPassword().trim().length() < MINIMUM_PASSWORD_LENGTH) {
          errors.rejectValue("password", "field.min.length",
                new Object[]{Integer.valueOf(MINIMUM_PASSWORD_LENGTH)},
                "The password must be at least [" + MINIMUM_PASSWORD_LENGTH + "] characters in length.");
       }
    }
 }

See also the Framework reference manual for a fuller discussion of the Validator interface and its role in an enterprise application.

从以下版本开始:

4.0

作者:

Rod Johnson

另请参阅:

• SmartValidator
• Errors
• ValidationUtils

方法概要

修饰符和类型	方法	说明
boolean	supports(Class<?> clazz)	Can this Validator validate instances of the supplied clazz?
void	validate(Object target, Errors errors)	Validate the supplied target object, which must be of a Class for which the supports(Class) method typically has (or would) return true.

方法详细资料

supports

boolean supports(Class<?> clazz)

Can this Validator validate instances of the supplied clazz?

This method is typically implemented like so:

return Foo.class.isAssignableFrom(clazz);

(Where Foo is the class (or superclass) of the actual object instance that is to be validated.)

参数:

clazz - the Class that this Validator is being asked if it can validate

返回:

true if this Validator can indeed validate instances of the supplied clazz

validate

void validate(Object target,
 Errors errors)

Validate the supplied target object, which must be of a Class for which the supports(Class) method typically has (or would) return true.

The supplied errors instance can be used to report any resulting validation errors.

参数:

target - the object that is to be validated

errors - contextual state about the validation process

另请参阅:

• ValidationUtils