Java EE 7：找不到“ http://java.sun.com/jsp/jstl/core”的标记库描述符

Question

I am trying to use the following tag lib in my JSP page :

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

But Eclipse shows me this error :

Can not find the tag library descriptor for "http://java.sun.com/jsp/jstl/core"

I am already having JSTL in my classpath using this dependency :

<dependency>
  <artifactId>javaee-api</artifactId>
  <version>7.0</version>
  <scope>provided</scope>
</dependency>

I use WildFly 9.

I have the same problem with these 2 other taglibs :

<%@ taglib prefix="f"  uri="http://java.sun.com/jsf/core"%>
<%@ taglib prefix="h"  uri="http://java.sun.com/jsf/html"%>

Remark : The following link is giving 404 HTTP error : http://central.maven.org/maven2/javax/servlet/jsp/jstl/jstl/1.2/jstl-1.2.jar

Thank you.

Answer 1

If your web application uses JSTL directly, for JSTL 1.0, the namespace is http://java.sun.com/jstl/core . In JavaEE 5, JSTL 1.1 is included, the namespace is http://java.sun.com/jsp/jstl/core . In JaveEE 6 and JavaEE 7, JSTL 1.2 is included, the namespace is http://java.sun.com/jsp/jstl/core .

But if your web application uses JSF+Facelets, for JSF 1.x+Facelets 1.x in JaveEE 5, the namespace is http://java.sun.com/jstl/core . For JSF 2.0+Facelets 2.x in JavaEE 6, the namespace is http://java.sun.com/jsp/jstl/core . For JSF 2.2+Facelets 2.2 in JavaEE 7, the namespace is http://xmlns.jcp.org/jsp/jstl/core .

Answer 2

The Java EE 7 Tutorial briefly states the new URIs for JSTL in the What Is Facelets section as :

• http://xmlns.jcp.org/jsp/jstl/core
• http://xmlns.jcp.org/jsp/jstl/functions

However, I have yet to find an implementation of the taglibs that use the URI. So the URIs (with their recommended namespaces) should be defined as:

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

And to get rid of the error you need an implementation of the JSTL loaded as a dependency in provided scope eg

<dependency>
  <groupId>jstl</groupId>
  <artifactId>jstl</artifactId>
  <version>1.2</version>
  <scope>provided</scope>
</dependency>

The provided scope prevents it from being included into the WAR file since the one being used by the application server should be used.