Skip to main content

Spring MVC, Spring Bean Validation Framework and validating confirm password / confirm email fields.

How to write validation like confirm password, confirm email and etc in Spring MVC.
NOTE: To make bean validation to work its nice to read this tutorial: <a href="http://wheelersoftware.com/articles/spring-bean-validation-framework.html"></a>
Today I was busy making some validations and implementations on very common scenario:
change email and password.
So we have a new password AND a new email also for both of them we have a confirm email/password field. And we want to validate everything nicely and to show to the user the real validation message if there is some error.
So ... I've to use a form which already uses some annotations like @NoBlank and etc I think everyone of you is using annotations framework if you don't use it SHAME ON YOU !:)

Anyway so I've added some fields to existing form bean:
private String newPassword;
private String confirmNewPassword;
private String newEmail;
private String confirmNewEmail;
Basiclly in my case this is very big form and none of this fields is mendatory so the user can leave all of them blank. My first idea was to add at least Length for the password and Email annotations for the email so I do:
@Length(min=6,max=20)
private String newPassword;
private String confirmNewPassword;
@Email
private String newEmail;
private String confirmNewEmail;
Ok but the confirm fields should have the same rules ? Maybe...
The problem that I saw is that length and email by default means NotBlank.
To make email validator to work or length validator they first check is the field blank. In my case I want the blank to be OK.. so I asked god google what to do.
The answer applyIf.
So at the end I get :
@Length(min = 6, max = 20, applyIf = "newPassword is not blank") //cool right ?
private String newPassword;
private String confirmNewPassword;
@Email(applyIf = "newEmail is not blank") //cool right ?
private String newEmail;
private String confirmNewEmail;
Cool right ? yep it is cool. but let me add the validation for confirmNewPassword and confirmNewEmail.
@Length(min = 6, max = 20, applyIf = "newPassword is not blank")
private String newPassword;
@NotBlank(applyIf = "newPassword is not blank")
private String confirmNewPassword;
@Email(applyIf = "newEmail is not blank")
private String newEmail;
@NotBlank(applyIf = "newEmail is not blank")
@Email(applyIf = "newEmail is not blank")
private String confirmNewEmail;
Nice.. so I have validation on new* fields only if they are not blank. Also I have a validation on the confirm fields only if again new* fields are not blank.
Cool... what left ? ahh the most hard part to check is the confirmpassword the same as the newPassword and is the confirmEmail same as the newEmail.
the first idea ofcourse is to write a custom validator.
So I write this :
class NewPassAndEmailValidator implements Validator {
    @Override
    public boolean supports(Class<?> clazz) {
        return PersonalDetailsFormBean.class.equals(clazz);
    }
    @Override
    public void validate(Object obj, Errors errors) {
        PersonalDetailsFormBean personalDetailsFormBean = (PersonalDetailsFormBean) obj;
        if (personalDetailsFormBean.getNewPassword() != null
                && !personalDetailsFormBean.getNewPassword().equals("")) {
            if (!personalDetailsFormBean.getNewPassword().equals(personalDetailsFormBean.getConfirmNewPassword())) {
                errors.rejectValue("confirmNewPassword", "PersonalDetailsFormBean.confirmNewPassword[customvalidator]");
            }
        }
        if (personalDetailsFormBean.getNewEmail() != null && !personalDetailsFormBean.getNewEmail().equals("")) {
            if (!personalDetailsFormBean.getNewEmail().equals(personalDetailsFormBean.getConfirmNewEmail())) {
                errors.rejectValue("confirmNewEmail", "PersonalDetailsFormBean.confirmNewEmail[customvalidator]");
            }
        }
    }
}
and then in the controller submit method.
validator.validate(personalDetailsFormBean, result); //this invokes the annotation based validator.
NewPassAndEmailValidator newPassAndEmailValidator = new NewPassAndEmailValidato();
newPassAndEmailValidator.validate(personalDetailsFormBean, result);
if (result.hasErrors()) {
... return...
}
This .... WORKS FINE. BUT... ah its not cool :( ... I mean even in struts 1 in 2001 we ware having a validation based on expression. AND we have even better way here... Awesome :D
So I've removed this validator... and write only "this":
@Expression(value = "confirmNewPassword = newPassword", applyIf = "newPassword is not blank")
So the final example looks like this:
@Length(min = 6, max = 20, applyIf = "newPassword is not blank")
private String newPassword;
@NotBlank(applyIf = "newPassword is not blank")
@Expression(value = "confirmNewPassword = newPassword", applyIf = "newPassword is not blank")
private String confirmNewPassword;
@Email(applyIf = "newEmail is not blank")
private String newEmail;
@NotBlank(applyIf = "newEmail is not blank")
@Email(applyIf = "newEmail is not blank")
@Expression(value = "confirmNewEmail = newEmail", applyIf = "newEmail is not blank")
private String confirmNewEmail;
:) ok this looks cool :D maybe not so cool than 20+ if statements to checks for null for some of you to but I like this way :))
Labels:

Comments

Unknown said…
This is exactly what I was looking for. Checking equality of fields using annotations. Great post, thanks.
September 1, 2010 at 12:55 AM
Reuben said…
Yes, very cool. Thanks for sharing.
September 3, 2010 at 6:39 PM
dai bang canh cut said…
Thanks a lot, JOke. The example of @Expression is very useful. I found it nowhere but here.

Kind regards
Vuong
September 7, 2010 at 5:22 PM
Unknown said…
Awesome Buddy..
thnx a million......
September 4, 2013 at 7:15 AM
Post a Comment

Popular Posts

Hibernate Generic DAO.

When you use Hibernate and DAO pattern it is a good idea to use a Generic Base Dao. The fallowing code snippet contains GenericDAO that is a base class for all my DAO classes. This GenericDAO uses HibernateDaoSupport from Spring for its implementation if you want you can use JpaDaoSupport or JdbcDaoSupport in your projects. My Generic DAO interface looks like this : package org.joke.myproject.dao.base; import java.io.Serializable; import java.util.List; /** * @author Naiden Gochev * @param <E> * @param <PK> */ public interface GenericDao<E,PK  extends Serializable> {     PK save(E newInstance);     void update(E transientObject);     void saveOrUpdate(E transientObject);     void delete(E persistentObject);     E findById(PK id);     List<E> findAll();     List<E> f...
10 comments
Read more

JavaEE 5 (JSF + JPA + EJB3) using Eclipse

Today I will show you how to create Enterprise Application using Java EE 5 and GlassFish. I will use - Eclipse 3.5 + WTP - GlassFish v. 2.1 - JSF Mojarra implementation. - EJB 3.0. - JPA Toplink essentials implementation. - MySQL No NetBeans or JDeveloper magic involved :) The prerequirement is: Add datasource in glassfish. Read this how you can make this here: http://gochev.blogspot.com/2009/10/creating-datasource-in-glassfish-v-21.html 1) First you need to add glassfish in your eclipse. - Go to Servers View - Right Click, New - Choose GlassFish v 2.1 if you dont have glassfish click on Download additional adapters link choose glassfish wait and restart eclipse. Than try again. 2) Create the database CREATE TABLE ` lesson ` . ` USERS ` ( ` id ` INTEGER UNSIGNED NOT NULL AUTO_INCREMENT, ` username ` VARCHAR ( 45 ) NOT NULL , ` password ` VARCHAR ( 45 ) NOT NULL , ` name ` VARCHAR ( 45 ) NOT NULL , PRIMARY KEY ( ` id ` ) ) ENGINE = InnoDB...
9 comments
Read more

Generate JavaDoc with UML diagrams

In my life many times has happened when I am assigned to a totally new project that I have no idea what it is about, that has to go live in 2 weeks and that I have to fix some issues in this ultra strange code sometimes even code written in different language. On my question is there any documentation the answer is: Yes but it is very old or no. So in short they want me to start working on a project with no documentation at all. My second question is is there a javadoc and the anwer is : yeah … kind of … so I am in a project with 30% javadoc with methods in French language for example ( I don’t know even a single word in French) so in short I am loosing 2 weeks to understand what is using what what is the model what is PersonnePhysique  and what is this crazy domain model. I believe this has happened with everyone of you at least once so what can you do ? You can start digging into the java code like crazy ( like everyone of us have tried many times) You can install ...
2 comments
Read more