JSTL - Core Library

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JSTL Core Library

JSTL core library can be introduced to a JSP page with:

<jsp:root xmlns:jsp="http://java.sun.com/JSP/Page" 
   xmlns:c="http://java.sun.com/jstl/core" version="1.2"> 

It provides the following basic scripting functions:

<c:out value="..."/>
<c:set var="..." value="..."/>
<c:if test="...">body</c:if>
<c:choose>body</c:choose>
<c:forEach items="...">body</c:forEach>
<c:forTokens items="..." delims="...">body</c:forTokens>

c:out Action

<c:out value="text_mixed_with_expressions"/>

The "value" attribute will be evaluated and the resulting value will be converted into a string which will be inserted into the HTTP response. The c:out action serves similar purposes as the JSP expression element.

c:set Action

<c:set var="name" value="expression"/>

The "var" attribute specifies a variable name, which will be declared and assigned with the value resulted from the "value" attribute. The c:set action serves similar purposes as the Java assignment statement.

c:if Action

<c:if test="expression"/>
body
</c:if>

If the "test" attribute is evaluated to true, body will be processed. The c:if action serves similar purposes as the Java if statement.

c:choose Action

<c:choose>
 <c:when test="expression">
  body
 </c:when>
 <c:when test="expression">
  body
 </c:when>
 ...
 <c:otherwise>
  body
 </c:otherwise>
</c:choose>

The body of the first c:when action that has the "test" attribute evaluated to true will be processed. If all "test" attributes are evaluated to false, the body of the c:otherwise action will be processed. The c:choose action serves similar purposes as the Java if-else statement.

(Continued on next part...)

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