This tag can be used to parameterize other tags. The parameters can be added with or without a name as key. when we declare the param tag, the value can be defined in either a value attribute or as text between the start and end tag. Struts behaves a bit different according to these two situations.
This tag has the following two parameters.
- name (String) – the name of the parameter
- value (Object) – the value of the parameter
The following Example will shows how to implement the ParamTag in the Struts2-
First we create a JSP file named success.jsp as follows.
<%@ page contentType="text/html; charset=UTF-8"%> <%@ taglib prefix="s" uri="/struts-tags"%> <html> <head> <title>Action Data Tag Struts2 | dineshonjava.com</title> </head> <body> <h2>An example of the param tag: </h2> <s:bean name="com.dineshonjava.struts2.action.DataTagAction" var="paramTag"> <s:param name="userName">Dinesh Rajput</s:param> <s:param name="userAge">27</s:param> <s:param name="userPhone">9998851234</s:param> <s:param name="userAddress">ABC Noida</s:param> </s:bean> <ol> <li>User Name : <s:property value="#paramTag.userName" /></li> <li>User Age : <s:property value="#paramTag.userAge" /></li> <li>User Phone : <s:property value="#paramTag.userPhone" /></li> <li>User Address : <s:property value="#paramTag.userAddress" /></li> </ol> </body> </html>
Configuration file in struts 2.
struts.xml
<?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.enable.DynamicMethodInvocation" value="false" /> <constant name="struts.devMode" value="false" /> <constant name="struts.custom.i18n.resources" value="myapp" /> <package name="default" extends="struts-default" namespace="/"> <action name="paramtag" class="com.dineshonjava.struts2.action.DataTagAction"> <result name="success">/success.jsp</result> </action> </package> </struts>
Create Action class
package com.dineshonjava.struts2.action; import com.opensymphony.xwork2.ActionSupport; /** * @author Dinesh Rajput * */ public class DataTagAction extends ActionSupport { private static final long serialVersionUID = -7744420104547018874L; private String userName; private String userAge; private String userPhone; private String userAddress; public String execute() { return SUCCESS; } public String sayHello() { return SUCCESS; } public String getUserName() { return userName; } public void setUserName(String userName) { this.userName = userName; } public String getUserAge() { return userAge; } public void setUserAge(String userAge) { this.userAge = userAge; } public String getUserPhone() { return userPhone; } public void setUserPhone(String userPhone) { this.userPhone = userPhone; } public String getUserAddress() { return userAddress; } public void setUserAddress(String userAddress) { this.userAddress = userAddress; } }
Your web.xml should look like:
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0"> <display-name>Struts2DataTag</display-name> <filter> <filter-name>struts2</filter-name> <filter-class> org.apache.struts2.dispatcher.FilterDispatcher </filter-class> </filter> <filter-mapping> <filter-name>struts2</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> </web-app>
Right click on the project name and click Export > WAR File to create a War file. Then deploy this WAR in the Tomcat’s webapps directory. Finally, start Tomcat server and try to access
URL http://localhost:8080/doj/paramtag.
This will give you following screen:
Download SourceCode
ParamDataTagExample.zip