Email 验证

import java.util.ArrayList;
import java.util.Collection;
import java.util.StringTokenizer;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;

import com.aerohive.core.annotation.Email;

public class EmailValidator implements ConstraintValidator<Email, String>{

    private String separator;
    
    @Override
    public void initialize(Email constraintAnnotation) {
        switch (constraintAnnotation.separator()) {
        case SEMICOLON:
        default:
            this.separator = ";";
            break;
        }
    }

    @Override
    public boolean isValid(String value, ConstraintValidatorContext context) {
        if(value == null) {
            return true;
        }
        Collection<String> invalidEmails = new ArrayList<> ();
        for (StringTokenizer token = new StringTokenizer(value.trim(), separator); token.hasMoreTokens();) {
            String email = token.nextToken();
            if(!isValidEmailAddress(email)) {
                invalidEmails.add(email);
            }
            
        }
        
        if(!invalidEmails.isEmpty()) {
            context.buildConstraintViolationWithTemplate("Invalid emails: " + invalidEmails).addConstraintViolation();
            return false;
        }
        
        return true;
    }
    
    
    private boolean isValidEmailAddress(String emailAddress) {
        Pattern p = Pattern.compile("\\w+([-+.]\\w+)*@\\w+([-.]\\w+)*\\.\\w+([-.]\\w+)*");
        Matcher m = p.matcher(emailAddress);
        return m.matches();
    }

}

@Target({ ElementType.METHOD, ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
@Constraint(validatedBy = {EmailValidator.class})
@Documented
public @interface Email {
    String message() default "{invalid.email}";

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

    Class<? extends Payload>[] payload() default {};
    
    EmailSeparator separator() default EmailSeparator.SEMICOLON;
}