10.2 Creating the View
The first file that the
user
navigates to is the view file
Ch10_01.jsp
. In this file, we use various custom Struts tags to implement the display you see in Example 10-1. For example, the
<html:form>
tag creates a Struts-enabled form that can display controls, as you see in Example 10-1; we're setting the form's
action
attribute to the
name
we'll give the controller,
Ch10_04.do
, so when the user clicks the Submit button (with the caption "Place your order"), the data in the form will be forwarded to the controller.
Example 10-1. A sample JSP
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib uri="/WEB-INF/struts-bean.tld" prefix="bean" %>
<%@ taglib uri="/WEB-INF/struts-html.tld" prefix="html" %>
<%@ taglib uri="/WEB-INF/struts-logic.tld" prefix="logic" %>
<%@ taglib uri="/Ch10" prefix="Ch10" %>
<HTML>
<HEAD>
<TITLE>Here's the menu...</TITLE>
</HEAD>
<BODY>
<H1>Here's the menu...</H1>
<html:errors/>
<Ch10:type/>
<Ch10:items/>
<html:form action="Ch10_04.do">
<TABLE>
<TR>
<TD ALIGN="LEFT" VALIGN="TOP">
<bean:message key="items"/>
<BR>
<logic:iterate id="items1" name="items">
<html:multibox property="items">
<%= items1 %>
</html:multibox>
<%= items1 %>
<BR>
</logic:iterate>
</TD>
<TD ALIGN="LEFT" VALIGN="TOP">
<bean:message key="type"/>
<BR>
<html:select property="type">
<html:options name="type"/>
</html:select>
</TD>
</TR>
<TR>
<TD ALIGN="LEFT">
<BR>
<bean:message key="email"/>
<html:text property="email"/>
</TD>
<TR>
</TABLE>
<BR>
<html:submit value="Place your order"/>
</html:form>
</BODY>
</HTML>
Create this file by right-clicking the
deployment
folder in Eclipse and selecting New
File, which automatically stores
Ch10_01.jsp
in the
webapps/Ch10_01
folder.
As you see in Figure 10-1, the drop-down list we're presenting holds the items Pizza, Calzone, and Sandwich, and you can see the list of ingredientsSausage, Cheese, Pepperoni, Meatballs, and Peppersrepresented with a list of checkboxes. To make the items in these lists available to Struts HTML control in the view, we'll use two custom JSP tags,
<Ch10:type>
to return items like Pizza and Calzone, and
<Ch10:items>
to return items like Sausage, Cheese, and Pepperoni. As you can see in Example 10-1, we use the Struts
<logic:iterate>
,
<html:multibox>
, and
<html:options>
tags to create the needed HTML controls from those lists of items. You can see the implementation of these custom tags in Example 10-2 and Example 10-3. In Eclipse, create these files and store them in the
src
folder by right-clicking that folder and selecting New
Class, placing the new classes,
Ch10_02
and
Ch10_03
, in the
org.eclipsebook.ch10
package.
Example 10-2. A custom tag class for order types
package org.eclipsebook.ch10;
import javax.servlet.jsp.tagext.TagSupport;
public class Ch10_02 extends TagSupport
{
public int doStartTag( )
{
String[] typeArray = {"", "Pizza", "Calzone", "Sandwich"};
pageContext.setAttribute("type", typeArray);
return SKIP_BODY;
}
}
Example 10-3. A custom tag class for pizza toppings
package org.eclipsebook.ch10;
import javax.servlet.jsp.tagext.TagSupport;
public class Ch10_03 extends TagSupport
{
public int doStartTag( )
{
String[] itemsArray = {"Sausage", "Cheese", "Pepperoni", "Meatballs", "Peppers"};
pageContext.setAttribute("items", itemsArray);
return SKIP_BODY;
}
}
To make these custom tags work, we need a tag library descriptor file, which you can see in Example 10-4. This file goes into
deployment\WEB-INF
.
Example 10-4. The TLD for the custom tags
<?xml version="1.0"?>
<!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.1//EN"
"http://java.sun.com/j2ee/dtds/web-jsptaglibrary_1_1.dtd">
<taglib>
<tlibversion>1.0</tlibversion>
<jspversion>1.2</jspversion>
<shortname>StrutsExample</shortname>
<info>
Supports the Struts Example
</info>
<tag>
<name>type</name>
<tagclass>org.eclipsebook.ch10.Ch10_02</tagclass>
<bodycontent>empty</bodycontent>
</tag>
<tag>
<name>items</name>
<tagclass>org.eclipsebook.ch10.Ch10_03</tagclass>
<bodycontent>JSP</bodycontent>
</tag>
</taglib>
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