Java Tutorial/JSTL/If
Содержание
JSTL If Else Statement
<source lang="java">
<%@ 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="${param.enter=="1"}">pizza.
</c:when>
<c:otherwise>pizzas.
</c:otherwise>
</c:choose>
</c:if>
<form method="post">Enter a number between 1 and 5:
<input type="text" name="enter" />
<input type="submit" value="Accept" />
</form>
</body>
</html></source>
JSTL If Statement
<source lang="java">
<%@ taglib uri="http://java.sun.ru/jstl/core" prefix="c" %> <html>
<head>
<title>If with Body</title>
</head>
<body>
<c:if test="${pageContext.request.method=="POST"}">
<c:if test="${param.guess=="5"}">You guessed my number!
</c:if>
<c:if test="${param.guess!="5"}">You did not guess my number!
</c:if>
</c:if>
<form method="post">Guess what number I am thinking of?
<input type="text" name="guess" />
<input type="submit" value="Try!" />
</form>
</body>
</html></source>
JSTL If Statement without Body
<source lang="java">
<%@ 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="${result}" />
</c:if>
<form method="post">Guess what number I am thinking of?
<input type="text" name="guess" />
<input type="submit" value="Try!" />
</form>
</body>
</html></source>
JSTL If Statement with True Value
<source lang="java">
<%@ taglib uri="http://java.sun.ru/jstl/core" prefix="c" %> <HTML>
<HEAD><TITLE>JSTL "if" tag</TITLE></HEAD> <BODY> <c:if test="true">Hello world!</c:if> </BODY>
</HTML></source>
JSTL If With Logical Operator And/Or
<source lang="java">
<%@ taglib prefix="c" uri="http://java.sun.ru/jstl/core" %> <%@ taglib prefix="fmt" uri="http://java.sun.ru/jstl/fmt" %> <html> <head> <title>EL Expression Examples</title> </head> <body>
EL Expression Examples
Logical Operators
<c:set var="guess" value="12"/>
Your guess is
<c:out value="${guess}"/>
<c:if test="${(guess >= 10) && (guess <= 20)}">
You"re in range!
</c:if> <c:if test="${(guess < 10) || (guess > 20)}">
Try again!
</c:if> </body> </html></source>
NULL value And Boolean
<source lang="java">
<%@ 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>
EL Expression Examples
Boolean and Null Values
<c:set var="StrVar" value="true"/> <c:if test="${StrVar}">
equal!
</c:if>
null == null
<c:out value="${null == null}"/>
</body> </html></source>
Set Test Result to Variable
<source lang="java">
<html>
<head> <title>Tag Plugin Examples: if</title> </head> <body>
Tag Plugin Examples - <c:if>
<font color="#000000"/> </br> <%@ taglib uri="http://java.sun.ru/jstl/core" prefix="c" %>
Set the test result to a variable
<c:if test="${1==1}" var="theTruth" scope="session"/>
The result of testing for (1==1) is: ${theTruth}
Conditionally execute the body
<c:if test="${2>0}">
It"s true that (2>0)!
</c:if>
</body>
</html></source>
