FieldError in Struts 2 Example

 

 
In our previous tutorial we learnt about actionError and actionMessage in struts 2, in this tutorial, we are going to describe the fielderror tags. The fielderror tag is a UI tag that renders field errors if they exist.
 


 
** UPDATE: Struts 2 Complete tutorial now available here.
 

Folder Structure

Action Class

 
Develop an action class using addFieldError(String fieldName, String errorMessage)method. This method adds an error message for a given field to the corresponding jsp page.

Here the error messages is added to each field individually using the addFieldError() method. The error messages can either be specified in a separate property file or can be added directly in the Action class itself.
 

package com.action;

import com.opensymphony.xwork2.ActionSupport;

public class LoginAction extends ActionSupport {

	private static final long serialVersionUID = 6677091252031583948L;

	private String userName;
	private String password;

	public String getPassword() {
		return password;
	}

	public void setPassword(String password) {
		this.password = password;
	}

	public String execute() {
		return SUCCESS;
	}

	public String getUserName() {
		return userName;
	}

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

	public void validate() {

		if (userName.isEmpty()) {
			addFieldError("userName", "Username can't be blank");
		}
		if (password.isEmpty()) {
			addFieldError("password", "Password Can't be blank");
		}
		else {
		addActionMessage("Welcome " + userName + ", You have been Successfully Logged in");
		}
	}
}

 
Here when either of userName or password is empty then fieldError is added this action via addFiedError method, so the execute method does not get invoked, and interceptors take case altering the flow of response by sending “error” string.
 
If userName and password are valid then a success message is added to actionMessage, the execute method get invoked, the jsp page get displayed based on execute methods returned value.
 
Recommended Article

JSP

 
File: Login.jsp
 
Create a jsp page that will display your field error messages (when fails to logged-in) using <s:fielderror/>tag as shown:
 

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






FieldError in Struts 2

 
File : Success.jsp
 

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






ActionError & ActionMessage Example
	

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ActionError & ActionMessage Example in Struts 2

struts.xml

 
Make sure that the struts.xml has the following mapping

 
     
	success.jsp
	login.jsp
     
 

 
The web.xml configuration is same as given in hello world programe.
 

Demo

 
On running the application
 

 
When Username or password is empty, display error message set by <s:fielderror/>
 

 
When Username and password is non empty, then application executes successfully and redirects to success.jsp and displays the ActionMessage setted in Validate method via <s:actionmessage/> tag.
 

 

Reference

 
FieldError Apache