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/*
Beginning JavaServer Pages
Vivek Chopra, Jon Eaves, Rupert Jones, Sing Li, John T. Bell
ISBN: 0-7645-7485-X
*/
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt" %>
<%@ taglib prefix="wroxtags" tagdir="/WEB-INF/tags" %>
<html>
<head>
<title>EL Expression Examples</title>
</head>
<body>
<h1>EL Expression Examples</h1>
<h2>Arithmetic Operators in Expressions</h2>
<c:set var="appleCount" value="${1 + 2 * 4 - 6 / 2}"/>
<b>There are ${1 + 2 * 4 - 6 / 2} apples on the table.</b><br/>
<b>There are
<fmt:formatNumber pattern="#####"> ${1 + 2 * 4 - 6 / 2}</fmt:formatNumber>
apples on the table.</b><br/>
<b>It feels like ${-4 - 8} degree today.</b><br/>
<c:set var="myGrade" value="11"/><br/>
<b>The average grade is ${(myGrade == 10) ? "perfect" : "good"}. </b><br/>
<b>There are ${23/54} remaining. </b><br/>
<b>There are ${6 div 2} apples on the table.</b><br/>
<b>There are ${2003 div 8} apples on the table.</b><br/>
<b>There are ${2003 mod 8} apples on the table.</b><br/>
<b>There are ${2003 % 8} apples on the table.</b><br/>
<h2>Logical Operators</h2>
<c:set var="guess" value="12"/>
<b>Your guess is ${guess}.</b><br/>
<c:if test="${(guess >= 10) && (guess <= 20)}">
<b>You're in range!</b><br/>
</c:if>
<c:if test="${(guess < 10) || (guess > 20)}">
<b>Try again!</b><br/>
</c:if>
<c:set var="guess" value="1"/>
<b>Your guess is ${guess}.</b><br/>
<c:if test="${(guess >= 10) and (guess <= 20)}">
<b>You're in range!</b><br/>
</c:if>
<c:if test="${(guess < 10) or (guess > 20)}">
<b>Try again!</b><br/>
</c:if>
<h2>Comparison Operators</h2>
4 > '3' ${4 > '3'}<br/>
'4' > 3 ${'4' > 3}<br/>
'4' > '3' ${'4' > '3'} <br/>
4 >= 3 ${4 >= 3}<br/>
4 <= 3 ${4 < 3}<br/>
4 == '4' ${4 == 4}<br/>
<h2>empty Operator</h2>
empty "" ${empty ""}<br/>
empty "sometext" ${empty "sometext"}<br/>
empty Junk ${empty Junk}<br/>
empty guess ${empty guess}<br/>
<h2>Boolean and Null Values</h2>
<c:set var="StrVar" value="true"/>
<c:if test="${StrVar}">
equal!
</c:if><br/>
null == null ${null == null}<br/>
"null" == null ${"null" == null}<br/>
</body>
</html>
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BeginningJavaServerPages-ch05-1.zip( 291 k)