Control Tags-If / Else If / Else
In this section we are going to discuss the various
control tags ( The Control Tags are used for flow control such as if, else and
iterate.)
'If' tag could be used by itself or with 'Else
If' Tag and/or single/multiple 'Else' Tag.
Create a JSP page IfControlTag.jsp.
Set a property 'technologyName' with a value 'Java'
as
<s:set name="technologyName" value="%{'Java'}"/>
Among if, elseif and else tags only one tag evaluates at a time.
Evaluation is based upon the conditions being processed. Evaluated conditions
must be of Boolean type. This is illustrated in the following Jsp page.
[Note:
If the condition in <s:if > tag
evaluates to 'true' then only this tag is evaluated and others are
discarded. As illustrated in the example.
If the condition in <s:if > tag
evaluates to 'false' and <s:elseif > tag evaluates to 'true'
then the body of the <s:elseif > tag is processed.
If the condition in <s:if >
tag and <s:elseif > tags evaluates to 'false' then
only the <s:else > tag is processed. ]
IfControlTag.jsp
<%@ taglib prefix="s" uri="/struts-tags" %>
<html>
<head>
<title>Struts 2 Control Tag Example</title>
</head>
<body>
<s:set name="technologyName" value="%{'Java'}"/>
<s:if test="%{#technologyName=='Java'}">
<div><s:property value="%{#technologyName}" /></div>
</s:if>
<s:elseif test="%{#technologyName=='Jav'}">
<div><s:property value="%{#technologyName}" /></div>
</s:elseif>
<s:else>
<div>Technology Value is not Java</div>
</s:else>
</body>
</html>
|
struts.xml: Add the following xml snippet
in the struts.xml file.
<action name="doIf" >
<result>/pages/genericTags/IfControlTag.jsp</result>
</action> |
index.jsp : Add the following jsp snippet in the
index.jsp file.
<ul>
<li><a href="roseindia/doIf.action">IF Control Tag Example</a></li>
</ul>
|
In the IfControlTag.jsp only <s:if> tag
evaluates to true
<s:if test="%{#technologyName=='Java'}">
<div><s:property value="%{#technologyName}" /></div>
</s:if>
So we get the output equal to Java
|
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Current Comments
2 comments so far (post your own) View All Comments Latest 10 Comments:Will this tag work within an 'iterator' tag along with s:set tag
Posted by Prabhu on Tuesday, 11.13.07 @ 18:09pm | #37232
I see all these examples that include an object or variable called 'test'. Where does this come from.
e.g.
s:if test="%{#technologyName=='Java'}">
Posted by John Chump on Saturday, 09.8.07 @ 00:19am | #26344