JSF 2 validateLength example

f:validateLength” is a JSF string length validator tag, which is used to check the length of a string. For example,


<h:inputText id="username" value="#{user.username}">
	<f:validateLength minimum="5" maximum="10" />
</h:inputText>

When this form is submitted, the validator will make sure the “username” text field contains a minimum length of 5, maximum length of 10.

“f:validateLength” example

A JSF 2.0 example to show the use of “f:validateLength” tag to validate the length of a “username” text field, when the validator failed, display the error message via “h:message” tag.

1. Managed Bean

A dummy managed bean to hold the “username” property only.


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 username;

	public String getUsername() {
		return username;
	}

	public void setUsername(String username) {
		this.username = username;
	}

}

2. JSF Page

JSF XHTML page, show the use of “f:validateLength” tag to make sure the form’s input “username” contains a minimum length of 5, maximum length of 10.


<?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"
      xmlns:c="http://java.sun.com/jsp/jstl/core"
      >
    <h:body>
    	
    	<h1>JSF 2 validateLength example</h1>
		
	<h:form>
		
		<h:panelGrid columns="3">
			
			Enter UserName : 
				
			<h:inputText id="username" value="#{user.username}" 
				size="20" required="true"
				label="UserName" >
				<f:validateLength minimum="5" maximum="10" />
			</h:inputText>
				
			<h:message for="username" style="color:red" />
			
		</h:panelGrid>
			
		<h:commandButton value="Submit" action="result" />
			
	</h:form>	
    </h:body>
</html>

3. Demo

Minimum length validation failed.

jsf2-ValidateLength-Example-1

Maximum length validation failed.

jsf2-ValidateLength-Example-2

Download Source Code

Download It – JSF-2-ValidateLength-Example.zip (9KB)

Reference

  1. JSF 2 validateLength JavaDoc

About the Author

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mkyong
Founder of Mkyong.com, love Java and open source stuff. Follow him on Twitter. If you like my tutorials, consider make a donation to these charities.

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KapilVladhosseinJSF 2.0 Tutorials Recent comment authors
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Kapil
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Kapil

how to restrict the unicode , suppose i am entering chineese/russian character in this field.

Vlad
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Vlad

Greetings. The tag h: inputText can change the description of the output error using reguiredMesage. It is possible to change the description of any errors in the tag f: validateLengtn?

hossein
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hossein

thank you

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[…] JSF 2 validateLength example “f:validateLength” is a JSF string length validator tag, which is used to check the length of a string. […]