Custom validator in JSF 2.0

In this article, we will show you how to create a custom validator in JSF 2.0

Steps

Create a validator class by implements javax.faces.validator.Validator interface.
Override validate() method.
Assign an unique validator ID via @FacesValidator annotation.
Reference custom validator class to JSF component via f:validator tag.

A detail guide to create a custom validator name “EmailValidator” – to validate email address via Java regular expression.

1. Folder Structure

Directory structure of this project.

2. Validator class

Create a custom validator class and implements javax.faces.validator.Validator interface.


package com.mkyong;

import javax.faces.validator.Validator;
public class EmailValidator implements Validator{
	//...
}

Overrides the validate() method.


public class EmailValidator implements Validator{

	public void validate(FacesContext context, UIComponent component,
			Object value) throws ValidatorException {
		//...
	}
}

Assign an unique validator ID with @FacesValidator.


package com.mkyong;

import javax.faces.validator.Validator;

@FacesValidator("com.mkyong.EmailValidator")
public class EmailValidator implements Validator{
	//...
}

See a full custom validator class :

EmailValidator.java


package com.mkyong;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.faces.application.FacesMessage;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.validator.FacesValidator;
import javax.faces.validator.Validator;
import javax.faces.validator.ValidatorException;

@FacesValidator("com.mkyong.EmailValidator")
public class EmailValidator implements Validator{

	private static final String EMAIL_PATTERN = "^[_A-Za-z0-9-]+(\\." +
			"[_A-Za-z0-9-]+)*@[A-Za-z0-9]+(\\.[A-Za-z0-9]+)*" +
			"(\\.[A-Za-z]{2,})$";

	private Pattern pattern;
	private Matcher matcher;
	
	public EmailValidator(){
		  pattern = Pattern.compile(EMAIL_PATTERN);
	}
	
	@Override
	public void validate(FacesContext context, UIComponent component,
			Object value) throws ValidatorException {
		
		matcher = pattern.matcher(value.toString());
		if(!matcher.matches()){
			
			FacesMessage msg = 
				new FacesMessage("E-mail validation failed.", 
						"Invalid E-mail format.");
			msg.setSeverity(FacesMessage.SEVERITY_ERROR);
			throw new ValidatorException(msg);

		}

	}
}

Above is a custom validator class, with id com.mkyong.EmailValidator. If email is invalid, returns FacesMessage error message.

Note
For detail explanation about the email regular expression pattern, please refer to this “Validate E-mail with Java regular expression” article.

3. Managed Bean

A normal managed bean named “user”, nothing special here.


package com.mkyong;

import java.io.Serializable;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.SessionScoped;
 
@ManagedBean(name="user")
@SessionScoped
public class UserBean implements Serializable{
	
	String email;

	public String getEmail() {
		return email;
	}

	public void setEmail(String email) {
		this.email = email;
	}

}

4. JSF Page

Reference above custom validator to JSF component via “validatorId” attribute in f:validator tag.

Spring DI into JSF custom validator
If you need @Autowired into JSF custom validator, uses binding, instead of validatorId. Read this post – Spring @Autowired into JSF custom validator.

default.xhtml


<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"   
      xmlns:h="http://java.sun.com/jsf/html"
      xmlns:f="http://java.sun.com/jsf/core"
      >
    <h:body>
    	
    <h1>Custom validator in JSF 2.0</h1>
		
	  <h:form>
		
		<h:panelGrid columns="3">
			
		  Enter your email :
				
		  <h:inputText id="email" value="#{user.email}" 
			size="20" required="true" label="Email Address">
			
			<f:validator validatorId="com.mkyong.EmailValidator" />
			
		  </h:inputText>
				
		  <h:message for="email" style="color:red" />
			
		</h:panelGrid>
			
		<h:commandButton value="Submit" action="result" />
			
	   </h:form>
	
    </h:body>
</html>

result.xhtml


<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"   
      xmlns:h="http://java.sun.com/jsf/html"
      >
    <h:body>
    	
    	<h1>Custom validator in JSF 2.0</h1>
			
	  <h:panelGrid columns="2">
			
		Email Address :  
		<h:outputText value="#{user.email}" />
				
	  </h:panelGrid>
			
    </h:body>
</html>

5. Demo

Validates email address via custom validator, if email address is invalid, return a error message.

Download Source Code

Download It – JSF-2-Custom-Validator-Example (10KB)

References

21 comments on “Custom validator in JSF 2.0”

aboalfazl
August 22, 2018 at 4:04 pm

Thank you so much

Arpit
October 7, 2016 at 5:29 am

thanks … i’m really very grateful for this article.

David
May 14, 2016 at 6:57 pm

Thanks man! Your tutorials are very easy to understand, everything is clear and everything works fine. I’ll visit your site every day from now 🙂

Naveen
November 7, 2015 at 12:34 pm

Hi,
in this example the error message hard coded in java, how to customize the error message using properties message bundle.

Daniel
June 3, 2015 at 9:21 am

I’m learning Java and I have to thank you a milion times !
Great site !

nits
March 16, 2015 at 11:59 pm

Thanks

??????? ???????
July 10, 2014 at 3:00 am

ru: ???????!
en: Thanks!

Cezar Cruz
March 27, 2014 at 2:42 am

Works for me! Thanks!

Sahil
April 25, 2013 at 2:37 am

Each time I try it, a new error message gets added to the popup instead of just showing it once. Any idea why?

Oppa
March 30, 2013 at 2:22 pm

Valeu demais!
thanks man!

balu
February 9, 2013 at 12:00 pm

issue got fixed.small mistake from my side, forgot to update the message on ajax request.

balu

February 9, 2013 at 11:46 am

Validation working but message is not displaying if required=”false” for email field.

Please find the code snippet below

<p:inputText autocomplete="off"  id="emailId" value="#{backingBean.emailID}" >
<f:validator validatorId="ldapmanager.EmailValidator"/>
</p:inputText>
<p:message id="errEmailId" for="emailId"/>

balu
February 9, 2013 at 11:42 am

Validation working but message is not displaying if required=”false” for email field.

Please find the code snippet below

Amin Oruji
July 29, 2012 at 5:39 pm

I love you man.

Chris
July 16, 2012 at 8:09 pm

Thank you for your small tutorial. Each time I’m looking quickly for something in JSF 2, you always show up first in Google and I found what I search. Continue your great works!!

Deepak
June 15, 2012 at 2:00 pm

Really very good blog. Thanks

Aditya
June 5, 2012 at 7:53 pm

I have a rich:datatable. I want to validate mandatory input fields in table. I want to show only one message for all mandatory field ie “please give some value for mandatory fields”.

Please tell me how to achieve this.

Lumia
March 27, 2012 at 9:23 pm
Hello sir i tried with same code for my application but i m getting error:
```
javax.servlet.ServletException: Expression Error: Named Object: checkemail not found.
	javax.faces.webapp.FacesServlet.service(FacesServlet.java:422)
```
1. megan
  April 4, 2012 at 10:36 pm
  
  I am getting the same! using JSF 2.0 with primefaces
  
2. megan
  April 4, 2012 at 10:46 pm
  
  I think you will find it is the
  
  @FacesValidator(“com.mkyong.EmailValidator”)
  
  line -it must point to the correct package that contains your validator!
  
  megan
  
Sreekanth
February 1, 2011 at 1:33 pm

Thanks for the tip.I started with JSF and this is a nice one.