Java Tutorial/JSTL/If
Версия от 17:44, 31 мая 2010; (обсуждение)
Содержание
JSTL If Else Statement
<%@ taglib uri="http://java.sun.ru/jstl/core" prefix="c" %>
<html>
<head>
<title>Using Choose,Otherwise and When</title>
</head>
<body>
<c:if test="${pageContext.request.method=="POST"}">Ok, we"ll
send
<c:out value="${param.enter}" />
<c:choose>
<c:when test="${param.enter=="1"}">pizza.
<br />
</c:when>
<c:otherwise>pizzas.
<br />
</c:otherwise>
</c:choose>
</c:if>
<form method="post">Enter a number between 1 and 5:
<input type="text" name="enter" />
<input type="submit" value="Accept" />
<br />
</form>
</body>
</html>
JSTL If Statement
<%@ taglib uri="http://java.sun.ru/jstl/core" prefix="c" %>
<html>
<head>
<title>If with Body</title>
</head>
<body>
<c:if test="${pageContext.request.method=="POST"}">
<c:if test="${param.guess=="5"}">You guessed my number!
<br />
<br />
<br />
</c:if>
<c:if test="${param.guess!="5"}">You did not guess my number!
<br />
<br />
<br />
</c:if>
</c:if>
<form method="post">Guess what number I am thinking of?
<input type="text" name="guess" />
<input type="submit" value="Try!" />
<br />
</form>
</body>
</html>
JSTL If Statement without Body
<%@ taglib uri="http://java.sun.ru/jstl/core" prefix="c" %>
<html>
<head>
<title>If with NO Body</title>
</head>
<body>
<c:if test="${pageContext.request.method=="POST"}">
<c:if test="${param.guess=="5"}" var="result" />
I tested to see if you picked my number, the result was
<c:out value="${result}" />
</c:if>
<form method="post">Guess what number I am thinking of?
<input type="text" name="guess" />
<input type="submit" value="Try!" />
<br />
</form>
</body>
</html>
JSTL If Statement with True Value
<%@ taglib uri="http://java.sun.ru/jstl/core" prefix="c" %>
<HTML>
<HEAD><TITLE>JSTL "if" tag</TITLE></HEAD>
<BODY>
<c:if test="true">Hello world!</c:if>
</BODY>
</HTML>
JSTL If With Logical Operator And/Or
<%@ taglib prefix="c" uri="http://java.sun.ru/jstl/core" %>
<%@ taglib prefix="fmt" uri="http://java.sun.ru/jstl/fmt" %>
<html>
<head>
<title>EL Expression Examples</title>
</head>
<body>
<h1>EL Expression Examples</h1>
<h2>Logical Operators</h2>
<c:set var="guess" value="12"/>
<b>Your guess is </b>
<c:out value="${guess}"/>
<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>
</body>
</html>
NULL value And Boolean
<%@ taglib prefix="c" uri="http://java.sun.ru/jstl/core" %>
<%@ taglib prefix="fmt" uri="http://java.sun.ru/jstl/fmt" %>
<html>
<head>
<title>EL Expression Examples</title>
</head>
<body>
<h1>EL Expression Examples</h1>
<h2>Boolean and Null Values</h2>
<c:set var="StrVar" value="true"/>
<c:if test="${StrVar}">
equal!
</c:if><br/>
null == null
<c:out value="${null == null}"/>
</body>
</html>
Set Test Result to Variable
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<html>
<head>
<title>Tag Plugin Examples: if</title>
</head>
<body>
<h1>Tag Plugin Examples - <c:if></h1>
<hr>
<font color="#000000"/>
</br>
<%@ taglib uri="http://java.sun.ru/jstl/core" prefix="c" %>
<h3>Set the test result to a variable</h3>
<c:if test="${1==1}" var="theTruth" scope="session"/>
The result of testing for (1==1) is: ${theTruth}
<h3>Conditionally execute the body</h3>
<c:if test="${2>0}">
It"s true that (2>0)!
</c:if>
</body>
</html>
