![]() |
The Java Developers Almanac 1.4Order this book from Amazon. |
e1064. Using the Java Standard Tag Library (JSTL) in a JSP PageThere are four tag libraries that make up the JSTL; see thejavax.servlet.jsp.jstl.* packages for examples that use these tag
libraries. JSTL is not yet a standard part of a JSP container.
Hence, in order to use the JSTL in a web application, you must include
a copy the JSTL library code in the WEB-INF directory of your web
application. These files are available in the Web Services Developer
Pack, which can be download from
http://java.sun.com/webservices/webservicespack.html .
A tag library has two parts: a Tag Library Descriptor (TLD)
file and a JAR file. The following ant elements copy the TLD files
from the Web Services Developer Pack into <%-- Copy TLD files from WSDP installation --%> <copy todir="${build}/WEB-INF/tld"> <fileset dir="${jwsdp.home}/tools/jstl/tld"> <include name="*.tld" /> </fileset> </copy> <%-- Copy JSTL jar files from WSDP installation --%> <copy todir="${build}/WEB-INF/lib"> <fileset dir="${jwsdp.home}/tools/jstl"> <include name="jstl.jar" /> </fileset> <fileset dir="${jwsdp.home}/tools/jstl/standard/lib"> <include name="standard.jar" /> </fileset> </copy>In order for a JSP page to use the JSTL, it must declare it's use on the page using the taglib directive. Here's an example
that declares the use of all four JSTL tag libraries:
<%-- Core --%> <%@ taglib uri="/WEB-INF/tld/c-rt.tld" prefix="c_rt" %> <%-- I18N Formatting --%> <%@ taglib uri="/WEB-INF/tld/fmt-rt.tld" prefix="fmt_rt" %> <%-- SQL --%> <%@ taglib uri="/WEB-INF/tld/sql-rt.tld" prefix="sql_rt" %> <%-- XML --%> <%@ taglib uri="/WEB-INF/tld/x-rt.tld" prefix="x_rt" %>The tags in the JSTL core tag library can then be referenced using the specified prefix as in: <c_rt:if test='<%= request.getParameter("param") != null %>'> <%= request.getParameter("param") %> </c_rt:if>See also e1065 Enabling the JSTL Expression Language in a JSP Page.
e1066. Getting a Request Parameter Using JSTL in a JSP Page e1067. Saving Data Using JSTL in a JSP Page e1068. Saving and Emitting HTML Fragments Using JSTL in a JSP Page e1069. Conditionally Generating Output Using JSTL in a JSP Page © 2002 Addison-Wesley. |