Struts 2 Validation, with Example, Struts2 Validation

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Software environment I have used for this example, so far as follows:
1. JDK 5.0
2. Tomcat 5.5.x
3. Eclipse 3.2
4. Apache Struts 2.1.6  (example Web application should have
   following JAR files in WEB-INF\lib folder)
   4.1. commons-fileupload-1.2.1.jar
   4.2. commons-io-1.3.2.jar
   4.3. commons-logging-1.1.jar
   4.4. freemarker-2.3.13.jar
   4.5. ognl-2.6.11.jar
   4.6. struts2-core-2.1.6.jar
   4.7. xwork-2.1.2.jar

   (Note: This example is not tested with any
     other version of Apache Struts )

We shall try to explore some more validations by using ready made
validators from Struts 2. Such as the String range and email field
validators.
So let us take each of these parts of this example and discuss:











index.jsp


<%@ taglib uri="/struts-tags" prefix="struts2"%>
<html>
<body>
<struts2:actionerror/>
<struts2:bean id="so" name="sample.SubscriptionOptions"/>
<struts2:bean id="consentOption" name="sample.ConsentOptions"/>
<struts2:form method="post" action="example" namespace="/sample">
<table>
<tr><td><struts2:textfield key="myBean.userName" label="Name "/></td></tr>
<tr><struts2:textfield key="myBean.roll" label="Roll "/></td></tr>
<tr><struts2:textfield key="myBean.email" label="Email "/></td></tr>
<tr><td><struts2:textfield key="myBean.section" label="Section "/></td></tr>
<tr><struts2:textfield key="myBean.stdClass" label="Std/Class "/></td></tr>
<struts2:checkbox key="myBean.newsLetterOption" label="Subscription for News Letters "/>
<struts2:checkboxlist label="Other Subscription Options " key="myBean.subscriptionOptions" list="so" labelSeparator=":"/>
<struts2:radio label="You opinion " key="myBean.consentOptions" list="consentOption" labelSeparator=":"/>
<tr><td colspan="2"><struts2:submit value="Register"/></td></tr>
</table>
</struts2:form>
</body>
</html>




The section in BOLD in this JSP is to add another email field.
Text with bold red color, shows that, any validation error will be shown on
this screen at the place of this actionerror TAG and just above each field
that is being validated.

struts.xml file will have a result name as "input", which is implicitly used
by validation for taking navigation to this result path.


<?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>
    <package name="hibernate-example" namespace="/sample"
                 extends="struts-default">
        <action name="example" class="sample.ExamplePOJOAction"
	                       method="preview">
                <result name="preview">/preview.jsp</result>
                <result name="input">/index.jsp</result>
        </action>
    </package>
</struts>





As mentioned earlier, the validation specific XML file, that holds
information about the field name and the type of declarative constraint
to be imposed on the field, this validation XML file will have to
be named as "ExamplePOJOAction-validation.xml" (Bold being Action class
name) and this validation XML file should be placed in the same folder where
the Action class is copied/available.



<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE validators PUBLIC
  	"-//OpenSymphony Group//XWork Validator 1.0.3//EN"
  	"http://www.opensymphony.com/xwork/xwork-validator-1.0.3.dtd">
<validators>
  <field name="myBean.userName">
    <field-validator type="requiredstring">
      <message>Please enter User name</message>
    </field-validator>
    <field-validator type="stringlength">
	  <param name="minLength">4</param>
	  <param name="mixLength">8</param>
      <message>Please enter total characters from 4 to 8</message>
    </field-validator>
  </field>
  <field name="myBean.email">
    <field-validator type="email">
      <message>Please enter proper email</message>
    </field-validator>
    <field-validator type="requiredstring">
      <message>Please enter your email</message>
    </field-validator>
  </field>
</validators>




So we have userName, email fields from MyBean class will be validated for
requiredstring, email and stringlength constraints/validations.

Action class can be same as that of earlier example and as shown below:
ExamplePOJOAction.java


package sample;
/**
 * This code is provided "AS IS" without any guaranty
 * Use of this code only for educational and learning
 * purpose only.
 * Author: Amit
 * Contact : usingframeworks@gmail.com
 * Date: 16-Feb-2009
 */
import java.util.Map;
import com.opensymphony.xwork2.ActionSupport;

/**
 * This is the Action POJO class
 */
public class ExamplePOJOAction extends ActionSupport {
    private MyBean myBean;
    public String preview() throws Exception {
        return "preview";
    }
    public void setMyBean(MyBean argMyBean) {
        myBean = argMyBean;
    }
    public MyBean getMyBean() {
        return myBean;
    }
}




All remaining supporting files can be obtained from my earlier example
from the link below:

Struts 2 Example

OR as follows:

Now Mybean is the class that is holding all the variables those will
be accepting values from Struts2 Tags from index.jsp file.
Now I am going to add another variable "consentOptions" of type java.util.List
and corresponding setter and getter methods.

MyBean.java

package sample;
/**
 * This code is provided "AS IS" without any guaranty
 * Use of this code only for educational and learning
 * purpose only.
 * Author: Amit
 * Contact : usingframeworks@gmail.com
 * Date: 16-Feb-2009
 */
import java.util.List;
import java.util.ArrayList;

public class MyBean
{
	private String userName;
	private String roll;
	private String email;
	private String section;
	private String stdClass;
	private List subscriptionOptions;
	private List consentOptions;
	private boolean newsLetterOption;

	public String getUserName() {
		return this.userName;
	}
	public void setUserName(String argUserName) {
		userName = argUserName;
	}
	public String getRoll() {
		return this.roll;
	}
	public void setRoll(String argRoll) {
		roll = argRoll;
	}
	public String getEmail() {
		return this.email;
	}
	public void setEmail(String argEmail) {
		email = argEmail;
	}
	public String getSection() {
		return this.section;
	}
	public void setSection(String argSection) {
		section = argSection;
	}
	public String getStdClass() {
		return this.stdClass;
	}
	public void setStdClass(String argStdClass) {
		stdClass = argStdClass;
	}
	public List getSubscriptionOptions() {
	    return subscriptionOptions;
	}
	public void setSubscriptionOptions(List argSubscriptionOptions) {
		subscriptionOptions = argSubscriptionOptions;
	}
	public void setNewsLetterOption(boolean argNewsLetterOption) {
		newsLetterOption = argNewsLetterOption;
	}
	public boolean getNewsLetterOption() {
		return newsLetterOption;
	}
	public void setConsentOptions(List argConsentOptions) {
        consentOptions = argConsentOptions;
	}
	public List getConsentOptions() {
		return consentOptions;
	}
}


And another class file that holds all the hard coded subscription options
for this example, those are to be shown in checkbox list as labels.

SubscriptionOptions.java

package sample;
/**
 * This code is provided "AS IS" without any guaranty
 * Use of this code only for educational and learning
 * purpose only.
 * Author: Amit
 * Contact : usingframeworks@gmail.com
 * Date: 16-Feb-2009
 */
import java.util.ArrayList;

public class SubscriptionOptions extends ArrayList
{
        public SubscriptionOptions() {
          super();
          add("Technical Support");
          add("Business Support");
          add("HR Support");
          add("Help Desk Emails");
        }
}


Just like Subscription options, I have introduced another class "ConsentOptions.java".
This class file holds all the labels for the radio buttons, like for this example,
these are "Agree" and "Disagree" .
ConsentOptions.java

package sample;
/**
 * This code is provided "AS IS" without any guaranty
 * Use of this code only for educational and learning
 * purpose only.
 * Author: Amit
 * Contact : usingframeworks@gmail.com
 * Date: 16-Feb-2009
 */
import java.util.ArrayList;

public class ConsentOptions extends ArrayList
{
	public ConsentOptions() {
          super();
          add("Agree");
          add("Disagree");
	}
}


Once all the fields in MyBean are populated with values from index.jsp
screen, then these values are to be shown in preview page, so comes the
preview.jsp file. There is a slight change in this preview.jsp file, to include
Radio button selectioned value, either Agree or Disagree.

preview.jsp

<%@ taglib uri="/struts-tags" prefix="struts2"%>
<html>
<head></head>
<body>
<h2>Preview Page</h2>
<table>
<tr><td>
<b><font color="green">Name : </font>
</td><td><struts2:property value="myBean.userName"/></td></tr>
<tr><td><b><font color="green">Roll No. : </font></b></td><td>
<struts2:property value="myBean.roll"/></td></tr>
<tr><td><b><font color="green">Email : </font></b></td><td>
<struts2:property value="myBean.email"/></td></tr>
<tr><td><b><font color="green">Section : </font>
</b></td><td><struts2:property value="myBean.section"/></td></tr>
<tr><td><b><font color="green">Std/Class : </font>
</b></td><td><struts2:property value="myBean.stdClass"/></td></tr>
<tr><td>
<b><font color="green">New Letter Subscription :</font></b></td><td>
<struts2:if test="myBean.newsLetterOption">
Yes
</struts2:if>
<struts2:else>
No
</struts2:else>
</td></tr>
<tr><td valign="top"><b><font color="green">Other Subscription Options:</font></b></td><td>
<struts2:iterator id="a" value="myBean.subscriptionOptions">
<struts2:property value="a"/>
<br>
</struts2:iterator>
</td></tr>

<tr><td valign="top"><b><font color="green">User consent Option selected :</font></b></td><td>
<struts2:iterator id="b" value="myBean.consentOptions">
<struts2:property value="b"/>
<br>
</struts2:iterator>
</td></tr>

</table>
</body>
</html>


If you are interested in setting up this example in tomcat web server,
following are some other files details such as

web.xml

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

<!DOCTYPE web-app
    PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
    "http://java.sun.com/dtd/web-app_2_3.dtd">

<web-app>
    <display-name>Struts Blank</display-name>
  <filter>
  <filter-name>sample-filter</filter-name>
  <filter-class>
    org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter
  </filter-class>
  </filter>
  <filter-mapping>
    <filter-name>sample-filter</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>
</web-app>


After running this example on Browser by using following URL:
http://localhost:8080/sample/index.jsp

One can just click submit button, then there will be violation of required string
validation logic and corresponding message will be displayed.
Then by entering three characters in name field (as 3 is not within 4 to 8
string length range), and clicking submit button will result in different
error message for name field.
Similarly for email field, there will be corresponding error message
if incorrect email id is entered for email field, like for example "test#test.com".

I shall be writing many more examples on using Validation with Struts2 Framework
and for various types of Struts2 Tags like Date type field, E-mail type field,
Numeric only fields and many more.


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