Struts HTML Tag Library
Struts HTML tag library provides tags which are used to create input forms and HTML user interfaces. The tags in the Struts HTML library form a bridge between a JSP view and the other components of a Web application. Since a dynamic Web application often depends on gathering data from a user, input forms play an important role in the Struts framework. Consequently, the majority of the HTML tags involve HTML forms.
Syntax to use Struts HTML tag library
<%@ taglib prefix="html" uri="http://struts.apache.org/tags-html" %>
< html:options >
< html:options > -renders a HTML option field.This Tag is valid only if nested inside < select> Tag.The element is used to display data of lists (arrays, collections) inside a select element.
Example Code for < html:options>
1.Create an Jsp page and name it as options.jsp.It is the Welcome page for a user.
options.jsp
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%@taglib prefix="html" uri="http://jakarta.apache.org/struts/tags-html" %>
<%@taglib prefix="bean" uri="http://jakarta.apache.org/struts/tags-bean" %>
< html>
< head>
< title> HTML File example </title>
< head>
< body bgcolor="#DDDDDD">
< h1 > Struts html:file example </h1>
< html:form action="/optn" >
< h3> Select Color:
< html:select name="optform" property="colors">
< html:option value="">--Select Color--< /html:option>
< html:options name="optform" property="colorlist" />
< /html:select>< br>
< html:submit value="Submit"/>< html:reset value="Reset"/>
< /h3>
< /html:form>
</body>
</html>
2.Create a Form bean.Form bean is used to hold the properties of the submitted form which is a sub class of ActionForm.Here we have three property to hold in tha form bean “colorlist”,”message” and “colors” of type ArrayList(Collection),Strings respectively.
optform.java
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;
public class optform extends org.apache.struts.action.ActionForm {
private String message;
private String colors;
ArrayList colorlist=new ArrayList();
public String getColors() {
return colors;
}
public void setColors(String colors) {
this.colors = colors;
}
public ArrayList getColorlist() {
ArrayList list=new ArrayList();
list.add(0,"Red");
list.add(1,"Blue");
list.add(2,"Green");
return list;
}
public void setColorlist(ArrayList colorlist) {
this.colorlist = colorlist;
}
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
public optform() {
super();
}
}
3.Simple Action class optaction.java which is a sub class of Action class used to process the user’s request.In this class we check for null values entered in the file input field and set their respective error message. The Message font color is set to the selected color from the drop down list from user.
optaction.java
package com.myapp.struts;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.action.ActionForward;
public class optaction extends org.apache.struts.action.Action {
/* forward name="success" path="" */
private final static String SUCCESS = "success";
private final static String FAILURE = "failure";
public ActionForward execute(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response)
throws Exception {
optform formBean=(optform)form;
if(formBean.getColors().equals(""))
{
formBean.setMessage("No Color is Selected from list");
return mapping.findForward(SUCCESS);
}
formBean.setMessage("< span style='color:"+formBean.getColors()+"'> U selected "+formBean.getColors()+" Color </span>");
return mapping.findForward(SUCCESS);
}
}
4.Create or modify struts config file struts-config.xml with action mappings.Struts-config file contains the information about the configuration of the struts framework to the application.It contains the action mappings which helps to select Action,ActionForm and other information for specific user’s request’s.
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts-config PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 1.2//EN"
"http://jakarta.apache.org/struts/dtds/struts-config_1_2.dtd">
< struts-config>
< form-beans>
< form-bean name="optform" type="com.myapp.struts.optform"/>
</form-beans>
< action-mappings>
< action name="optform" path="/optn" scope="request" type="com.myapp.struts.optaction" validate="false">
< forward name="success" path="/output.jsp"/>
</action>
</action-mappings>
</struts-config>
5.Create another simple Jsp page output.jspwhich is for displaying the output Message.If nothing is selected from the drop down list sets the respective error message and get displayed .If The color is selected from the drop down the message is set to display the message in selected font color in this page.
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%@ taglib uri="http://jakarta.apache.org/struts/tags-bean" prefix="bean" %>
< html>
< head>
< meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
< title> Struts HTML Output Page </title>
</head>
< body bgcolor="#DDDDDD">
< h1> < bean:write name="optform" property="message" filter="false"/> </h1>
</body>
</html>
6.Building and running the application
Output
Access page:http://localhost:8084/options/
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