Struts Validation Framework Tutorial with example.
- By Viral Patel on January 22, 2009
Apache Struts has changed the way we develop a Web application. Since its inception as an MVC architecture, Struts has been extensively used in J2EE world to develop robust, extendable and effective web applications.
Introduction to Struts Validation Framework
One of the important features of Struts framework is Struts Validation framework that performs validation on incoming form data. Validation framework was introduced by David Winterfeldt as an external plugin to Struts framework. It’s functionality has since been split so that validator can serve as the basis for a independant component and is now part of Jakarta Commons.The Struts framework’s simple validation interface alleviates much of the headache associated with handling data validation, allowing you to focus on validation code and not on the mechanics of capturing data and redisplaying incomplete or invalid data.
In order to do form validation without Validator framework, one has to use validate() method of the form bean (ActionForm class) to perform this task. Also one has to handle error messages during manual validation. Lot of fields that we validate require same logic to validate them, hence code is unneccessarily duplicated (if not managed properly).
Validation framework comes with set of useful routines to handle form validation automatically and it can handle both server side as well as client side form validation. If certain validation is not present, you can create your own validation logic and plug it into validation framework as a re-usable component.
Validator uses two XML configuration files to determine which validation routines should be installed and how they should be applied for a given application, respectively. The first configuration file, validator-rules.xml, declares the validation routines that should be plugged into the framework and provides logical names for each of the validations. The validator-rules.xml file also defines client-side JavaScript code for each validation routine. Validator can be configured to send this JavaScript code to the browser so that validations are performed on the client side as well as on the server side.
The second configuration file, validation.xml, defines which validation routines should be applied to which Form Beans. The definitions in this file use the logical names of Form Beans from the struts-config.xml file along with the logical names of validation routines from the validator-rules.xml file to tie the two together.
Using the Validator framework involves enabling the Validator plug-in, configuring Validator’s two configuration files, and creating Form Beans that extend the Validator’s ActionForm subclasses. The following sections explain in detail how to configure and use Validator.
Create a Struts project
Create a struts web application project. I assume you have working environment set for a Struts project. If not then go through the tutorial: Creating Struts application using Eclipse and create a struts project.
Create Form Beans
Create a form bean in your project called CustomerForm and copy following code in it.
package net.viralpatel.struts.validation.form;
import org.apache.struts.validator.ValidatorForm;
public class CustomerForm extends ValidatorForm {
private String name;
private String telephone;
private String email;
private int age;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getTelephone() {
return telephone;
}
public void setTelephone(String telephone) {
this.telephone = telephone;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
}
We will use this validator plugin to validate this form. Note that the form bean is extended from class ValidatorForm and not ActionForm as we generally do in Struts project.
Add Validator Plug-in in struts-config.xml
In order to use Validator in our project we need to configure it in struts-config.xml file. For this add following code in your struts-config.xml file.
<!-- Validator Configuration --> <plug-in className="org.apache.struts.validator.ValidatorPlugIn"> <set-property property="pathnames" value="/WEB-INF/validator-rules.xml, /WEB-INF/validation.xml" /> </plug-in>
This definition tells Struts to load and initialize the Validator plug-in for your application. Upon initialization, the plug-in loads the comma-delimited list of Validator config files specified by the pathnames property. Each config file’s path should be specified by use of a Web application-relative path, as shown in the previous example.
Define validations for the form
Create a file validation.xml in your applications WEB-INF directory. And copy following content in it.
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE form-validation PUBLIC
"-//Apache Software Foundation//DTD Commons Validator Rules Configuration 1.1.3//EN"
"http://jakarta.apache.org/commons/dtds/validator_1_1_3.dtd">
<form-validation>
<global>
<constant>
<constant-name>telephoneFormat</constant-name>
<constant-value>^\d{5,10}$</constant-value>
</constant>
</global>
<formset>
<form name="CustomerForm">
<field property="name" depends="required">
<arg key="label.name" />
</field>
<field property="age" depends="required, integer, intRange">
<arg0 key="label.age" />
<arg1 key="${var:min}" resource="false"/>
<arg2 key="${var:max}" resource="false"/>
<var>
<var-name>min</var-name>
<var-value>1</var-value>
</var>
<var>
<var-name>max</var-name>
<var-value>125</var-value>
</var>
</field>
<field property="telephone" depends="required, mask">
<arg key="label.telephone" />
<arg1 key="label.telephone" />
<var>
<var-name>mask</var-name>
<var-value>${telephoneFormat}</var-value>
</var>
</field>
<field property="email" depends="email">
<arg0 key="label.email" />
<arg1 key="label.email" />
</field>
</form>
</formset>
</form-validation>
In the above xml file, we have defined the rules for form validation. Note that we are validating form CustomerForm and the fields being validated are name, age, telephone and email. <field> tag defines the validation for a property of form. We can specify different rules like required, integer, email, intRange, mask etc in depends attribute of field tag..
Also you can define constants that can be reused in the validation xml using global constants tag.
Struts-config.xml entry for the action
Following is the entry in struts-config.xml file which maps the Action to our Validator form.
<form-beans> <form-bean name="CustomerForm" type="net.viralpatel.struts.validation.form.CustomerForm" /> </form-beans> ... ... ... <action-mappings> ... <action path="/customer" name="CustomerForm" validate="true" input="/index.jsp" type="net.viralpatel.struts.validation.action.CustomerAction"> <forward name="success" path="/Customer.jsp" /> <forward name="failure" path="/index.jsp" /> </action> ... </action-mappings>
Configuring ApplicationResources.properties
Struts validation framework uses externalization of the error messages. The messages are stored in a property file (ApplicationResource.properties) and are referred by the key values. Copy following in your ApplicationResource.properties (or MessageResource.properties).
label.name= Name
label.email= Email
label.telephone= Telephone
label.age= Age
# general error msgs
errors.header=<font size="2"><UL>
errors.prefix=<LI><span style="color: red">
errors.suffix=</span></LI>
errors.footer=</UL></font>
errors.invalid={0} is invalid.
errors.maxlength={0} can not be greater than {1} characters.
errors.minlength={0} can not be less than {1} characters.
errors.range={0} is not in the range {1} through {2}.
errors.required={0} is required.
errors.byte={0} must be an byte.
errors.date={0} is not a date.
errors.double={0} must be an double.
errors.float={0} must be an float.
errors.integer={0} must be an integer.
errors.long={0} must be an long.
errors.short={0} must be an short.
Create JSP to display the form
Create a JSP file called index.jsp and copy following content in it.
<%@ taglib uri="http://struts.apache.org/tags-html" prefix="html"%> <%@ taglib uri="http://struts.apache.org/tags-bean" prefix="bean"%> <html> <head> <title>Struts Validation Framework example.</title> </head> <body> <html:errors /> <html:javascript formName="CustomerForm" /> <html:form action="/customer"> <bean:message key="label.name" /> <html:text property="name"></html:text> <br /> <bean:message key="label.age" /> <html:text property="age"></html:text> <br /> <bean:message key="label.email" /> <html:text property="email"></html:text> <br /> <bean:message key="label.telephone" /> <html:text property="telephone"></html:text> <br /> <html:submit value="Submit"></html:submit> </html:form> </body> </html>
Running the application
We are done with our application. Now execute it from any web container (Tomcat in my case) and open in browser.
Enter any invalid value in the form and press submit.
Post your comments / doubts on this tutorial.
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I want to know the flow of this example. I tried this i m not getting the output. so please help me.
when i submit all bean property goes to success.jsp but the validation part is not working.
plug in rules& validation.xml are added.
eclipse & tomcat6.0 i am using.
errors on console after submit —->
ug 19, 2010 4:42:49 PM org.apache.struts.validator.ValidatorForm validate
SEVERE: org.apache.struts.validator.FieldChecks.validateRequired(java.lang.Object, org.apache.commons.validator.ValidatorAction, org.apache.commons.validator.Field, org.apache.struts.action.ActionErrors, javax.servlet.http.HttpServletRequest)
org.apache.commons.validator.ValidatorException: org.apache.struts.validator.FieldChecks.validateRequired(java.lang.Object, org.apache.commons.validator.ValidatorAction, org.apache.commons.validator.Field, org.apache.struts.action.ActionErrors, javax.servlet.http.HttpServletRequest)
at org.apache.commons.validator.ValidatorAction.loadValidationMethod(ValidatorAction.java:627)
at org.apache.commons.validator.ValidatorAction.executeValidationMethod(ValidatorAction.java:557)
at org.apache.commons.validator.Field.validateForRule(Field.java:827)
at org.apache.commons.validator.Field.validate(Field.java:906)
at org.apache.commons.validator.Form.validate(Form.java:174)
at org.apache.commons.validator.Validator.validate(Validator.java:367)
at org.apache.struts.validator.ValidatorForm.validate(ValidatorForm.java:110)
at org.apache.struts.action.RequestProcessor.processValidate(RequestProcessor.java:950)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:207)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:849)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:454)
at java.lang.Thread.run(Unknown Source)
Viral its a diff. problem — when i am connected to the NET the code works fine …. i have given the URI of jsp html & bean tld of ” WEB-INF ” so what should i do to work at a stand alone system.
pls help. Thank in advance.
Hi Viral,
Can you please tell me where to put properties file in our application..
Thanx in advance..
hi suhasini,,,,make a source folder on Java Resources and create a new file with the name applicationresources.properties in it,,,,,thats it.
Hi friends
I have executed above login application. These are the errors I got.
exception
org.apache.jasper.JasperException: javax.servlet.ServletException: javax.servlet.jsp.JspException: ValidatorResources not found in application scope under key “org.apache.commons.validator.VALIDATOR_RESOURCES”
root cause
javax.servlet.ServletException: javax.servlet.jsp.JspException: ValidatorResources not found in application scope under key “org.apache.commons.validator.VALIDATOR_RESOURCES”
org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:850)
root cause
javax.servlet.jsp.JspException: ValidatorResources not found in application scope under key “org.apache.commons.validator.VALIDATOR_RESOURCES”
org.apache.struts.taglib.html.JavascriptValidatorTag.renderJavascript(JavascriptValidatorTag.java:373)
Could u plz help me to solve these errors…….
Thankz in advance.
thanks
hello sir,
this example is very good, but u explain different validations,
I am getting Error :– Exception creating bean of class CustomerForm.
Please help
When I ran this program I got an error mentioning….java.lang.NullPointerException: Depends string “required” was not found in validator-rules.xml.
please tell me what I need do now?
I’ve tried to execute this Struts validator example:
But when running on server, its giving the below error:
Feb 4, 2011 12:23:15 AM org.apache.catalina.core.AprLifecycleListener init
INFO: The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: C:\Program Feb 4, 2011 12:23:16 AM org.apache.tomcat.util.digester.SetPropertiesRule begin
WARNING: [SetPropertiesRule]{Server/Service/Engine/Host/Context} Setting property ‘source’ to ‘org.eclipse.jst.jee.server:StrutsValidationExample’ did not find a matching property.
Feb 4, 2011 12:23:16 AM org.apache.coyote.http11.Http11Protocol init
INFO: Initializing Coyote HTTP/1.1 on http-8000
Feb 4, 2011 12:23:16 AM org.apache.catalina.startup.Catalina load
INFO: Initialization processed in 942 ms
java.lang.NoClassDefFoundError: org/apache/commons/validator/ValidatorResourcesInitializer
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:414)
Caused by: java.lang.ClassNotFoundException: org.apache.commons.validator.ValidatorResourcesInitializer
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1491)
… 22 more
Feb 4, 2011 12:23:22 AM org.apache.catalina.core.StandardContext loadOnStartup
SEVERE: Servlet /StrutsValidationExample threw load() exception
java.lang.ClassNotFoundException: org.apache.commons.validator.ValidatorResourcesInitializer
at org.apache.struts.validator.ValidatorPlugIn.initResources(ValidatorPlugIn.java:224)
SEVERE: Servlet.service() for servlet jsp threw exception
java.lang.NoSuchMethodError: org.apache.commons.validator.ValidatorResources.get(Ljava/util/Locale;Ljava/lang/Object;)Lorg/apache/commons/validator/Form;
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
Please provide Your example code for download . so that Fresher can understand easily
I m getting the below error.Plz help me
SEVERE: Servlet.service() for servlet jsp threw exception
javax.servlet.jsp.JspException: ValidatorResources not found in application scope under key “org.apache.commons.validator.VALIDATOR_RESOURCES”
at org.apache.struts.taglib.html.JavascriptValidatorTag.renderJavascript(JavascriptValidatorTag.java:373)
at java.lang.Thread.run(Thread.java:619)
I also getting the ValidatorResources not found – error, and nothing I have done so far seems to make this go away.
I am using a struts 1.2 with commons-validator-1.3.1.jar hope this doesn’t mess things up for me. Pls help if possible.
Thanks… Good Explanation.. But I would like to know the meaning of this line. “<html:javascript formName="CustomerForm" " . That is Any javascript is written or it will taken from xml file?
i am working the struts validation for login page. I am not able to test the password consecutive.
can you please help me how to test password consecutive.
Like:- Admin123 is correct password
AAdmin123 in not correct
Regards,
Pitch
Hello!!
I tried to excute the thing, but the things are not working. One thing i want to ask is that ypu ahve mentioned about the validation-rules.xml. But you ahve not given any code for this xml file. SO can you plaes brief me about this validation-rules.xml . Thanks in advance.
i m getting http:status404 exception that the application cannot receive the Servlet action .
kindly help me .
Thanks in advance.
Hi Sir,
This example is good & easy to understand.
But, where is the CustomerAction.java file?
How to write that? Which logic has to implement in that?
Thanks & Regards,
Satya.
i m getting the following error.. reply fast.
A form must be defined in the Commons Validator configuration when dynamicJavascript=”true” is set.
also i want to show the error msgs in an alert box.
Hi,
I am new to struts.. Can you please provide the CustomerAction class and customer.jsp files..
Hi,
I was wondering about this line “”, you put it into the code but you are not using it at all. By other hand, javascript code should be included into tags, i say “should” and not “must” because is not really mandatory but including javascript this way is just a matter of order. Back to the topic, that javascript line allows you to do the validation before the data is send to the server, so this saves you time and bandwidth, to use it you must add an event to your form, on the sample jsp code just put the form line like this: , so now instead of get some messages on the page body the messages will appear in a pop-up warning window