java 用于验证给定字符串中的日期格式的Java Annotation

Posted 2021-05-08

import com.google.common.base.Strings;
import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

public class ValidDateValidator implements ConstraintValidator<ValidDate, String> {

    private Boolean isOptional;

    @Override
    public void initialize(ValidDate validDate) {
        this.isOptional = validDate.optional();
    }

    @Override
    public boolean isValid(String value, ConstraintValidatorContext constraintValidatorContext) {

        boolean validDate = isValidFormat("yyyy/MM/dd", value);

        return isOptional ? (validDate || (Strings.isNullOrEmpty(value))) : validDate;
    }

    private static boolean isValidFormat(String format, String value) {
        Date date = null;
        try {
            SimpleDateFormat sdf = new SimpleDateFormat(format);
            if (value != null){
                date = sdf.parse(value);
                if (!value.equals(sdf.format(date))) {
                    date = null;
                }
            }

        } catch (ParseException ex) {
        }
        return date != null;
    }
}

import javax.validation.Constraint;
import javax.validation.Payload;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;

import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.PARAMETER;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

/**
 * Validate that the annotated string is in YYYY/MM/DD Date format
 */

@Target({FIELD, PARAMETER})
@Retention(RUNTIME)
@Constraint(validatedBy = ValidDateValidator.class)
public @interface ValidDate {

    String message() default "invalid date";

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

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

    boolean optional() default false;
}