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 if, else and iterate.)

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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 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

Java

     

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Control Tags-If / Else If / Else

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Comments:1
Yangzhongjie
June 30, 2011
<s:if test="@com.rjgc......................">

Hello: I want to kown .How to call the method of class in struts tags.Thank you!

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