With this example we are going to see how to create a conditional content in a JSP page. JavaServer Pages (JSP) is a server-side programming technology that enables the creation of dynamic, platform-independent method for building Web-based applications. JSP have access to the entire family of Java APIs, including the JDBC API to access enterprise databases. In short, to create an if-then-else statement in a jsp page one should follow these steps:
- Create a jsp page that begins with the
<%code fragment%>scriptlet. It can contain any number of JAVA language statements, variable or method declarations, or expressions that are valid in the page scripting language. - Keep any html tags in the page outside the scriptlet.
- Create the java if-then-else statement inside the scriptlet, but close the scriptlet at each line. HTML text can be included between scriptlet tags.
An example of a conditional content in a jsp page is below:
ConditionalContent.jsp
<%@ page language="java" contentType="text/html;charset=UTF-8" %>
<html>
<head>
<title>Java Code Geeks Snippets - Condition Content in JSP Page</title>
</head>
<body>
<%
if ("myvalue".equals(request.getParameter("myparam"))) {
%>
This will be printed if parameter myparam equals with myvalue
<%
}
else {
%>
This will be printed if parameter myparam DOES NOT equal with myvalue
<%
}
%>
</body>
URL:
http://localhost:8080/jcgsnippets/ConditionalContent.jsp?myparam=myvalue
Output:
This will printed if parameter myparam equals with myvalue
This was an example on how to create a conditional content in a JSP page.
This is an anti-pattern. You should avoid mixing java code with html like this. You ought instead to use JSTL.
<%@ taglib prefix='c' uri='http://java.sun.com/jsp/jstl/core' %> <c:set var="isiPad" value="value"/> <c:choose> <!-- if condition --> <c:when test="${...}">Html Code</c:when> <!-- else condition --> <c:otherwise>Html code</c:otherwise> </c:choose>