JSF - f:validateLength

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f:validateLength tag is used to validate length of a string value in a particular range.

JSF Tag

<f:validateLength minimum="5" maximum="8" />

Tag Attributes

S.N.Attribute & Description
1minimum
a String with a minimum number of characters
2maximum
a String with a maximum number of characters

Example Application

Let us create a test JSF application to test the above tag.

StepDescription
1Create a project with a name helloworld under a package com.tutorialspoint.test as explained in the JSF - First Application chapter.
2Modify home.xhtml as explained below. Keep rest of the files unchanged.
3Create result.xhtml in the webapps directory as explained below.
4Create UserData.java as a managed bean under package com.tutorialspoint.test as explained below.
5Compile and run the application to make sure business logic is working as per the requirements.
6Finally, build the application in the form of war file and deploy it in Apache Tomcat Webserver.
7Launch your web application using appropriate URL as explained below in the last step.

UserData.java

package com.tutorialspoint.test;

import java.io.Serializable;

import javax.faces.bean.ManagedBean;
import javax.faces.bean.SessionScoped;

@ManagedBean(name = "userData", eager = true)
@SessionScoped
public class UserData implements Serializable {

   private static final long serialVersionUID = 1L;

   private String name;
  
   public String getName() {
      return name;
   }
   public void setName(String name) {
      this.name = name;
   }  
}

home.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:head>
      <title>JSF tutorial</title>			
   </h:head>
   <h:body> 
   <h2>h:validateLength Example</h2>
   <h:form>
      <h:inputText id="nameInput" value="#{userData.name}" 
         label="name" >
         <f:validateLength minimum="5" maximum="8" />
      </h:inputText>			
      <h:commandButton value="submit" action="result"/>
      <h:message for="nameInput" style="color:red" />
   </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:f="http://java.sun.com/jsf/core"    
   xmlns:h="http://java.sun.com/jsf/html">
   <h:head>
      <title>JSF Tutorial!</title>   
   </h:head>
   <h:body>
      <h2>Result</h2>
      <hr />
      Name: #{userData.name}     
   </h:body>
</html>  

Once you are ready with all the changes done, let us compile and run the application as we did in JSF - First Application chapter. If everything is fine with your application, this will produce following result:

JSF f:validateLength

Enter an invalid value

JSF f:validateLength1

Enter a valid value

JSF f:validateLength2

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