{"id":743,"date":"2009-09-15T16:24:33","date_gmt":"2009-09-15T06:24:33","guid":{"rendered":"https:\/\/eisabainyo.net\/weblog\/?page_id=743"},"modified":"2020-12-21T20:20:12","modified_gmt":"2020-12-21T10:20:12","slug":"introduction-to-jsp-standard-tag-library-jstl-basics","status":"publish","type":"page","link":"https:\/\/eisabainyo.net\/weblog\/introduction-to-jsp-standard-tag-library-jstl-basics\/","title":{"rendered":"Introduction to JSP Standard Tag Library (JSTL Basics)"},"content":{"rendered":"

Tag libraries to include in your .jsp page<\/strong><\/p>\n

<%@ taglib prefix="c" uri="http:\/\/java.sun.com\/jsp\/jstl\/core" %>
\n<%@ taglib prefix="fmt" uri="http:\/\/java.sun.com\/jsp\/jstl\/fmt" %>
\n<%@ taglib prefix="fn" uri="http:\/\/java.sun.com\/jsp\/jstl\/functions" %><\/p>\n

Include file (Java)<\/strong><\/p>\n

<%@ include file="\/WEB-INF\/jsp\/common\/date.jsp" %><\/pre>\n
Include file (JSP)<\/strong><\/p>\n
<jsp:include page="\/WEB-INF\/jsp\/common\/date.jsp">\r\n\t<jsp:param name="title" value="Date and Time"\/>\r\n<\/jsp:include><\/pre>\n
Import a URL<\/strong><\/p>\n
<c:import url="http:\/\/www.google.com">\r\n\t<jsp:param name="title" value="Google"\/>\r\n<\/c:import><\/pre>\n
Set a variable to be used within the page<\/strong><\/p>\n
<c:set var="title" value="Web Developmenent Blog"\/><\/pre>\n
This can be used inside the jsp page by calling ${title}<\/p>\n
For each loop<\/strong><\/p>\n
<c:forEach items="${result}" varStatus="status" var="item">\r\n\t${item.title}\r\n<\/c:forEach><\/pre>\n
For each loop with a pre-determined limit<\/strong><\/p>\n
Display the first 3 items<\/p>\n
<c:forEach items="${result}" varStatus="status" \r\nvar="item" begin="0" end="2">\r\n\t...\r\n<\/c:forEach><\/pre>\n
Check if it is the last item in the loop<\/strong><\/p>\n
<c:forEach items="${items}" var="item" varStatus="status">\r\n\t${item}<c:if test="${not status.last}">, <\/c:if>\r\n<\/c:forEach><\/pre>\n
If condition<\/strong><\/p>\n
<c:if test="${not empty title}">\r\n\tTitle isn't empty\r\n<\/c:if><\/pre>\n
If condition with more than one possible result<\/strong><\/p>\n
<c:choose>\r\n   \t<c:when test="${linkNameLen > 18}">\r\n   \t\t<c:set var='linkNameShort' value='${fn:substring(link.linkName, 0, 18)}...'\/>\r\n   \t<\/c:when>\r\n   \t<c:otherwise>\r\n    \t\t<c:set var='linkNameShort' value='${link.linkName}'\/>  \t\t\t\t\r\n   \t<\/c:otherwise>\r\n<\/c:choose><\/pre>\n
Are you a developer? Want to get a promotion, work on interesting projects, land a high paying job at a tech company or stand out from the crowd? <\/h3>\n
Then this ebook is for you!<\/h4>\n
Career Guide for Software Developers<\/a><\/p>\n
\"Career<\/a><\/div>\n
Display a subset of a string<\/strong><\/p>\n
Display only the first 80 characters<\/p>\n
${fn:substring(url, 0, 80)}<\/pre>\n
Count the total number of characters in a string<\/strong><\/p>\n
<c:if test="${fn:length(url) > 80}">...<\/c:if><\/pre>\n
Replace certain characters in a string<\/strong><\/p>\n
<c:set var="description" \r\nvalue="${fn:replace(string, 'Old Text', 'New Text')}" \/><\/pre>\n
Convert string to all lowercases<\/strong><\/p>\n
${fn:toLowerCase(string)}<\/pre>\n
Check if a string contains certain value<\/strong><\/p>\n
<c:if test="${not empty param.gender && \r\nfn:contains(param.gender,'Female')}"> checked="checked"<\/c:if><\/pre>\n
Split a string into an array<\/strong><\/p>\n
Eg: Split 14\/10\/2009<\/p>\n
<c:set var="date" value="${fn:split(start_date, '\/')}" \/>  \r\n<c:set var="day" value="${date[0]}" \/>\r\n<c:set var="month" value="${date[1]}" \/>\r\n<c:set var="year" value="${date[2]}" \/><\/pre>\n
Check if a string starts with certain characters<\/strong><\/p>\n
<c:choose>\r\n\t<c:when test="${fn:startsWith(website,'http') }">\r\n\t\t<a href="${website}">${website}<\/a>\r\n\t<\/c:when>\r\n\t<c:otherwise>\r\n\t\t<a href="http:\/\/${website}">http:\/\/${website}<\/a>\r\n\t<\/c:otherwise>\r\n<\/c:choose><\/pre>\n
Display text with html values escaped<\/strong><\/p>\n
<c:out value="${summary}"\/><\/pre>\n
Display text with html values<\/strong><\/p>\n
<c:out value="${cat.name}" escapeXml="false"\/><\/pre>\n
Escape html values (same result as using <c:out>)<\/strong><\/p>\n
${fn:escapeXml(summary)}<\/pre>\n
OR operator<\/strong><\/p>\n
<c:if test="${(title == 'null') || (empty title)}">\r\n\t...\r\n<\/c:if><\/pre>\n
AND operator<\/strong><\/p>\n
<c:if test="${(title != 'null') && (title == 'Page 1')}">\r\n\t...\r\n<\/c:if><\/pre>\n
Maths operators<\/strong><\/p>\n
Addition<\/p>\n
<c:if test="${counter + 2 == 4}"><\/pre>\n
Subtraction<\/p>\n
<c:if test="${counter - 2 == 0}"><\/pre>\n
Multiplication<\/p>\n
<c:if test="${counter * 2 == 4}"><\/pre>\n
Division<\/p>\n
<c:if test="${counter \/ 2 == 4}"><\/pre>\n
Remainder<\/p>\n
<c:if test="${counter % 2 == 0}"><\/pre>\n
Form a URL with parameters<\/strong><\/p>\n
<c:url value="http:\/\/www.google.com\/search" var="google_search">\r\n\t<c:param name="q" value="web development blog"\/>\r\n\t<c:param name="hl" value="en"\/>\r\n<\/c:url><\/pre>\n
<c:out value="${google_search}"\/><\/pre>\n
Check a parameter from URL<\/strong><\/p>\n
<c:if test="${param.name != 'null' && not empty param.name}">\r\n\t...\r\n<\/c:if><\/pre>\n
Check session<\/strong><\/p>\n
<c:when test="${not empty sessionScope['javax.portlet.userinfo']}"><\/pre>\n
Check if form is submitted<\/strong><\/p>\n
<c:if test="${pageContext.request.method == 'POST'}">\r\n\t...\r\n<\/c:if><\/pre>\n
Other JSP\/JSTL Resources<\/h3>\n