ActionError & ActionMessage Example in Struts 2

 
In this tutorial we will learn about ActionError & ActionMessage class and its usage.
 

 
a) ActionError class is used to send error feedback message to user and it get rendered in jsp by using <s:actionerror/> tag.
 
b) ActionMessage class – is used to send information feedback message to user, and it get rendered in jsp using <s:actionmessage/> tag.
 
** UPDATE: Struts 2 Complete tutorial now available here.
 
In this tutorial we will use the previous tutorials example to implement the functionality of ActionError and ActionMessage class.
 

 
Here’s a simple login form, display the error message (actionerror) if the username is empty, Otherwise redirect to another page and display the a welcome message (actionmessage).
 

1. Folder Structure

Action Class

 
The action class, do a simple checking to make sure that the username is not empty, if the userName is not valid then the action class set the error message with addActionError() , if its valid then it set the successful message with addActionMessage().
 

package com.action;

import com.opensymphony.xwork2.ActionSupport;

public class LoginAction extends ActionSupport {

	private static final long serialVersionUID = 6677091252031583948L;

	private String userName;

	public String execute() {

		return SUCCESS;
	}

	public String getUserName() {
		return userName;
	}

	public void setUserName(String userName) {
		this.userName = userName;
	}

	public void validate() {
		if (userName.isEmpty()) {
		addActionError("Username can't be blanked");
		} else {
		addActionMessage("Welcome " + userName + ", You have been Successfully Logged in");
		}
	}
}

 
You might be interested to read:

• jQuery form validation using jQuery Validation plugin
• FieldError in Struts 2 Example

JSP

 
Two simple JSP pages with css style to customize the error message.
 
login.jsp
 

<%@taglib uri="/struts-tags" prefix="s"%>






ActionError & ActionMessage Example
	
	

 
success.jsp
 

<%@ taglib prefix="s" uri="/struts-tags"%>






ActionError & ActionMessage Example
	

struts.xml

 
The mapping in struts.xml should be as below

	
		
			success.jsp
			login.jsp
		
	

Run it

 
http://localhost:8089/ActionErrorMessage/

 
When Username is invalid, display error message with <s:actionerror/>
 

 
When Username is valid, display welcome message <s:actionmessage/>
 

 

Note:

 
In struts 2 when you use <s:actionerror /> tag, it displays the errors with bullets, read the article on Change default style of s:actionerror / s:actionmessage tag in order to remove this