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>