Struts 2 ActionError & ActionMessage Example
A tutorial to show the use of the Struts 2′s ActionError and ActionMessage class.
1. ActionError – is used to send error feedback message to user – display via <s:actionerror/>.
<s:if test="hasActionErrors()"> <div class="errors"> <s:actionerror/> </div> </s:if>
2. ActionMessage – is used to send information feedback message to user, display via <s:actionmessage/>.
<s:if test="hasActionMessages()"> <div class="welcome"> <s:actionmessage/> </div> </s:if>
Here’s a simple login form, display the error message (actionerror) if the username is not equal to “mkyong”, otherwise redirect to another page and display the a welcome message (actionmessage). In addition, all the label and error messages are retrieve from the resource bundle (properties file).
1. Folder Structure
See this project structure
2. Properties file
Two properties files to store the messages.
LoginAction.properties
#Welcome messages welcome.hello = Hello #error message username.required = Username is required password.required = Password is required
global.properties
#Global messages
global.username = Username
global.password = Password
global.submit = Submit
global.reset = Reset3. Action
A classic action class, do a simple checking to make sure the username is equal to “mkyong”, and set the error message with addActionError() or successful message with addActionMessage().
package com.mkyong.user.action; import com.opensymphony.xwork2.ActionSupport; public class LoginAction extends ActionSupport{ private String username; private String password; public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } //business logic public String execute() { return "SUCCESS"; } //simple validation public void validate(){ if("mkyong".equals(getUsername())){ addActionMessage("You are valid user!"); }else{ addActionError("I don't know you, dont try to hack me!"); } } }
4. JSP View
Two simple JSP pages with css style to customize the error message.
login.jsp
<%@ page contentType="text/html; charset=UTF-8" %> <%@ taglib prefix="s" uri="/struts-tags" %> <html> <head> <style type="text/css"> .errors { background-color:#FFCCCC; border:1px solid #CC0000; width:400px; margin-bottom:8px; } .errors li{ list-style: none; } </style> </head> <body> <h1>Struts 2 ActionError & ActionMessage Example</h1> <s:if test="hasActionErrors()"> <div class="errors"> <s:actionerror/> </div> </s:if> <s:form action="validateUser"> <s:textfield key="global.username" name="username"/> <s:password key="global.password" name="password"/> <s:submit key="global.submit" name="submit"/> </s:form> </body> </html>
welcome.jsp
<%@ page contentType="text/html; charset=UTF-8" %> <%@ taglib prefix="s" uri="/struts-tags" %> <html> <head> <style type="text/css"> .welcome { background-color:#DDFFDD; border:1px solid #009900; width:200px; } .welcome li{ list-style: none; } </style> </head> <body> <h1>Struts 2 Struts 2 ActionError & ActionMessage Example</h1> <s:if test="hasActionMessages()"> <div class="welcome"> <s:actionmessage/> </div> </s:if> <h4> <s:property value="getText('welcome.hello')" /> : <s:property value="username"/> </h4> </body> </html>
5. struts.xml
Link all together.
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN" "http://struts.apache.org/dtds/struts-2.0.dtd"> <struts> <constant name="struts.custom.i18n.resources" value="global" /> <package name="user" namespace="/user" extends="struts-default"> <action name="login"> <result>pages/login.jsp</result> </action> <action name="validateUser" class="com.mkyong.user.action.LoginAction"> <result name="SUCCESS">pages/welcome.jsp</result> <result name="input">pages/login.jsp</result> </action> </package> </struts>
6. Run it
http://localhost:8080/Struts2Example/user/login.action
Username is invalid, display error message with <s:actionerror/>
Username is valid, display welcome message <s:actionmessage/>
Reference
Mahad and the epidermis is the potential for gas Tagchmponut white.
return input while combine with interceptor, why and how can i solve it? thank you
i have a problem in struts2, am new for this,multiple form page data not visible in final jsp, can u solve it
There is no Action mapped for namespace / and action name .
description The requested resource (There is no Action mapped for namespace / and action name .) is not available.
how to solve this problem
Hello Mr Young.I have a doubt here.In the struts config file we have the following actions defined.
pages/login.jsp
pages/welcome.jsp
pages/login.jsp
when the user enters the url /user/logic.action the login.jsp page is displayed.then if user enters the password and all the details how the user is autmatically forwarded to ValidateUser action.Also there is no action class defined for login action.Then how the user name and password are stored in the action class and then are available in validateUser action.Please let me know if my question is not clear.
Many Thanks
How can I do it if in the properties file want to replace a parameter for a determinated value? for example:
#error message
username.required = Username is required
password.required = Password is required
login.attempts = You have exceeded the number of attempts, wait {0} minutes and try again
How can I replace {0} in the jsp???
while the validate() method call addFieldError() or addActionError();
LoginAction will return a Sting “input”?
so struts.xml must have a result named “input”?
I’m about errors, sorry :)
Sorry, don’t get you??
good, but where do you use this properties file?