3.Struts-Applying programmatic validations

1.In web applications in the most of the cases an application is need to check whether input values

are entered by a client or not, before the processing logic

2.While applying validations on input, we can define Java script code to do validations at client

side and we can also defined validations at form bean class by overriding validate method to

implement Server side validations.

3. In a Struts Applicaion, to implement validations at Server side manually then we use to override

validate method of ActionForm class into our FormBean class.

4. While overriding validate method in FormBean class, we create following objects.

i. ActionErrors class

ii. ActionMessage class.

5. If validation error is occurred then we create ActionMessage class object and encapsulates Action

Message class and encapsulate the error message key in the Resource Bundle File.

6. In validate method we need to store all ActionMessage objects into AtionErrors objects it means

ActionErrors object is a group of ActionMessage objects.

7. ActionServlet that is Controller calls validate the method of a FormBean, before moving the

Control to execute(-,-,-,-) of an Action class.

Login.jsp

<%@ taglib uri="http://struts.apache.org/tags-bean" prefix="bean" %>

<%@ taglib uri="http://struts.apache.org/tags-html" prefix="html" %>

<%@ taglib uri="http://struts.apache.org/tags-logic" prefix="logic" %>

<%--

Document : login

Created on : Oct 8, 2013, 11:30:41 AM

Author : Satya<satyanarayana@greenbuds.co.in & satyajohnny@live.com>

--%>

<%@page contentType="text/html" pageEncoding="UTF-8"%>

<!DOCTYPE html>

<html>

<head>

</head>

<body>

<h1>Hello World!</h1>

<html:form action="/login">

<bean:message key="label.user"/> <html:text property="uname"/> 

<html:errors property="uname"/><br/>

<bean:message key="label.pwd"/><html:password property="pwd"/> 

<html:errors property="pwd"/><br/><br/>

<html:submit value="ok"/>

</html:form>

</body>

</html>

LoginForm

__________

* To change this template, choose Tools | Templates

* and open the template in the editor.

package com.myapp.struts;

import javax.servlet.http.HttpServletRequest;

import org.apache.struts.action.ActionErrors;

import org.apache.struts.action.ActionMapping;

import org.apache.struts.action.ActionMessage;

/**

* @author Satya<satyanarayana@greenbuds.co.in & satyajohnny@live.com>

public class LoginForm extends org.apache.struts.action.ActionForm {

private String uname;

private String pwd;

public String getUname() {

return uname;

}

public void setUname(String uname) {

this.uname = uname;

}

public String getPwd() {

return pwd;

}

public void setPwd(String pwd) {

this.pwd = pwd;

}

@Override

public ActionErrors validate(ActionMapping mapping, HttpServletRequest request) {

ActionErrors errors = new ActionErrors();

if(uname.isEmpty())

{

ActionMessage m1 = new ActionMessage("user.req");

errors.add("uname", m1);

} if(pwd.isEmpty())

{

ActionMessage m2 = new ActionMessage("pwd.req");

errors.add("pwd",m2);

}

return errors;

}

Struts.config.xml

<?xml version="1.0" encoding="UTF-8" ?>

<!DOCTYPE struts-config PUBLIC

"-//Apache Software Foundation//DTD Struts Configuration 1.3//EN"

"http://jakarta.apache.org/struts/dtds/struts-config_1_3.dtd">

<struts-config>

<form-beans>

<form-bean name="LoginForm" type="com.myapp.struts.LoginForm"/>

</form-beans>

<global-exceptions>

</global-exceptions>

<global-forwards>

</global-forwards>

<action-mappings>

</action-mappings>

<message-resources parameter="com/myapp/struts/ApplicationResource"/>

<message-resources parameter="com/myapp/struts/satya" />

<!--

This plugin initialize Tiles definition factory. This later can takes some

parameters explained here after. The plugin first read parameters from

web.xml, thenoverload them with parameters defined here. All parameters

are optional.

The plugin should be declared in each struts-config file.

- definitions-config: (optional)

Specify configuration file names. There can be several comma

separated file names (default: ?? )

- moduleAware: (optional - struts1.1)

Specify if the Tiles definition factory is module aware. If true

(default), there will be one factory for each Struts module.

If false, there will be one common factory for all module. In this

later case, it is still needed to declare one plugin per module.

The factory will be initialized with parameters found in the first

initialized plugin (generally the one associated with the default

module).

true : One factory per module. (default)

false : one single shared factory for all modules

- definitions-parser-validate: (optional)

Specify if xml parser should validate the Tiles configuration file.

true : validate. DTD should be specified in file header (default)

false : no validation

Paths found in Tiles definitions are relative to the main context.

-->

<plug-in className="org.apache.struts.tiles.TilesPlugin" >

<set-property property="definitions-config" value="/WEB-INF/tiles-defs.xml" />

<set-property property="moduleAware" value="true" />

</plug-in>

<plug-in className="org.apache.struts.validator.ValidatorPlugIn">

<set-property

property="pathnames"

value="/WEB-INF/validator-rules.xml,/WEB-INF/validation.xml"/>

</plug-in>

</struts-config>

Error Message Identifying:

500 error: If we get 500 Errros-Module „null‟ found then we have to check <load-

not in web.xml file, is there any problem in Resource Bundle File and check once s

and every thing.

Java.lang.NoClassFoundError: If we find this error verify struts-taglib.jar. havin

The absolute uri: If we get this error check once uri whether it is correct or not.

3.Struts-Applying programmatic validations

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3.Struts-Applying programmatic validations

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