Validations using Struts 2 Annotations
Validating Struts 2 Login Application using Annotations
In this section we are going to validate our login application using Annotations
in Action class. Our current login application does not validate the user
against the database. Instead login name and passwords are validated against the
hardcode values (User: Admin and Password: Admin) in the actions class.
Working of the application
- Login page is displayed to take the inputs.
- User enters user name and password and then clicks
on the "Login" button.
- User validation is done in action class and if user
enters Admin/Admin in the user name/password fields, then success pages is
displayed. Otherwise the error message is displayed on the screen.
Steps to develop the application
Here are simple and easy steps to develop Login page in
the using Struts 2 framework.
- Develop Login Form
The GUI of the application consists of login form (log-in.jsp) and
success message page (loginsuccess.jsp) .
The log-in.jsp is used to display the login page to the user. In our
application it is saved in "webapps\struts2tutorial\pages\"
folder. Here is the code of log-in.jsp file:
<%@ taglib prefix="s" uri="/struts-tags"
%>
<html>
<head>
<title>Struts 2 Login Application!</title>
<link href="<s:url value="/css/main.css"/>"
rel="stylesheet" type="text/css"/>
</head>
<body>
<s:form action="AnnotationAction" method="POST" validate="true">
<tr>
<td colspan="2">
Login
</td>
</tr>
<tr>
<td colspan="2">
<s:actionerror
/>
<s:fielderror
/>
</td>
</tr>
<s:textfield name="username" label="Login
name"/>
<s:password name="password"
label="Password"/>
<s:submit value="Login" align="center"/>
</s:form>
</body>
</html>
|
The code :
<s:actionerror />
<s:fielderror />
displays action errors and field validation errors.
The code <s:form
action="AnnotationAction"
method="POST" validate="true">
generates the html form for the
application.
The code :
<s:textfield name="username"
label="Login name"/>
<s:password name="password" label="Password"/>
generates Login Name and Password fields.
The submit button is generated through <s:submit
value="Login" align="center"/> code.
The loginsuccess.jsp page displays the Login Success message when
user is authenticated successfully. Here is the code of loginsuccess.jsp
file:
| <html>
<head>
<title>Login
Success</title>
</head>
<body>
<p align="center"><font
color="#000080" size="5">Login
Successful</font></p>
</body>
</html>
|
- Developing Action class (using Annotations
to validate Login forms)
Now let's develop the action class to handle the login request. The Struts 2 framework provides a
base ActionSupport class to implement commonly used interfaces. In our
action class (AnnotationAction.java) we have
extended ActionSupport class and imported the com.opensymphony.xwork2.validator.annotations
package .
For validating the login application java script can be
added to the jsp page or in action class, but Struts 2 provides another very
easy method to validate your form fields using annotations in the action class.
Two annotations are needed,
1. The @Validation annotation tells to Struts that action in this
class might need to be validated.
2. The @RequiredStringValidator annotation is used for the text input
to hold a singular value.
Rest of the care is taken by the framework.
Our
"AnnotationAction" class is saved in the "webapps\struts2tutorial\WEB-INF\src\java\net\roseindia"
directoy. Here is the code of AnnotationAction.java action class:
In this class we will write the code to validate the login page.
AnnotationAction.java
package net.roseindia;
import com.opensymphony.xwork2.ActionSupport;
import com.opensymphony.xwork2.validator.annotations.*;
@Validation
public class AnnotationAction extends ActionSupport {
private String username = null;
private String password = null;
@RequiredStringValidator(message="Supply name")
public String getUsername() {
return username;
}
public void setUsername(String value) {
username = value;
}
@RequiredStringValidator(message="Supply password")
public String getPassword() {
return password;
}
public void setPassword(String value) {
password = value;
}
public String execute() throws Exception {
System.out.println("Validating login");
if(!getUsername().equals("Admin") || !getPassword().equals("Admin")){
addActionError("Invalid user name or password! Please try again!");
return ERROR;
}
else{
return SUCCESS;
}
}
}
|
-
Configuring action mapping (in struts.xml)
Now we will create action mapping in the struts.xml file. Here is the code
to be added in the struts.xml:
<action name="LoginAnnotation">
<result>/pages/log-in.jsp</result>
</action>
<action name="AnnotationAction" class="net.roseindia.AnnotationAction">
<result name="input">/pages/log-in.jsp</result>
<result name="error">/pages/log-in.jsp</result>
<result>/pages/loginsuccess.jsp</result>
</action>
|
In the above mapping the action "LoginAnnotation"
is used to display the login page and "AnnotationAction" validates the user
using action class (AnnotationAction.java).
- CSS file (main.css)
This css file is used to enhance the presentation of the login form. The main.css
is saved into "\webapps\struts2tutorial\css" directory.
Here is the code of main.css:
@CHARSET "UTF-8";
body {
font: 12px verdana, arial, helvetica, sans-serif;
background-color:#FFFFFF;
}
table.wwFormTable {
font: 12px verdana, arial, helvetica, sans-serif;
border-width: 1px;
border-color: #030;
border-style: solid;
color: #242;
background-color: #ada;
width: 30%;
margin-left:35%;
margin-right:35%;
margin-top:15%;
}
table.wwFormTable th {
}
table.wwFormTable tr td {
background-color: #dfd;
margin: 5px;
padding: 5px;
}
.tdLabel {
/*
border-width: 1px;
border-color: #afa;
border-style: solid;
*/
font-weight: bold;
align: top;
}
.label {
}
.errorMessage {
color: red;
font-size: 0.8em;
}
#headerDiv {
border-style: solid;
border-width: 1px 1px 0px;
border-color: black;
padding: 5px;
background-color: #7a7;
/* height: 22px; */
height: 1.8em;
/* margin-bottom: 12px; */
}
#buttonBar {
border-width: 0px 1px 1px;
border-style: solid;
border-color: black;
color: white;
margin-bottom: 12px;
background-color: #7a7;
height: 1.6em;
padding: 5px;
}
#appName {
color: white;
font-size: 1.8em;
}
#pageTitle {
font-size: 1.4em;
color: #dfd;
clear: none;
}
#appName, #pageTitle {
float: right;
}
#menuContainer {
float: left;
}
#brandingContainer {
float: right:
text-align: right;
} |
Compiling the application
To compile the application go to "\webapps\struts2tutorial\WEB-INF\src"
directory and type ant command. The ant tool will compile the application for
you.
Adding the link into index.html
Finally we add the link in the index.html to
access the login form.
<ul>
<li><a href="roseindia/LoginAnnotation.action">Action Annotation Example</a></li>
</ul>
Output:
If you click Login button without filling the fields, you will get the output pages as :
If you fill only the "Login name" field
and click Login button without filling the next fields, you will get
the output pages as :
If you fill the wrong information
and click the Login button, you will get the output pages as :
If you fill the correct information
and click the Login button, you will get the output pages as :
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