Not being able to locate TLD file?

[Arvind Mahendra]

I am trying to run an example on Ch7 of JavaServerPages 3rd ed. by Hans Bergsten.
My TLD file resides inside the WEB-INF folder called taglib.tld
My TLD looks like

<?xml version="1.0" encoding="ISO-8859-1" ?>
<taglib xmlns="http://java.sun.com/xml/ns/j2ee"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
    [url=http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd"]http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd"[/url]
  version="2.0">
 <description>
    A tag library for the examples in the O'Reilly JSP book, 3rd edition
  </description>
  <tlib-version>3.0</tlib-version>
  <short-name>ora</short-name>
  <uri>orataglib</uri>
 
 <tag>
    <description>
       Adds a message to the page
    </description>
    <name>motd</name>
    <tag-class>com.ora.jsp.tags.xmp.MixedMessageTag</tag-class>
    <body-content>empty</body-content>
 
    <attribute>
      <name>category</name>
      <required>true</required>
      <rtexprvalue>true</rtexprvalue>
    </attribute>
  </tag>

this is what the beginning 2 lines of my message.jsp look like:

<%@ page contentType="text/html" %>
<%@ taglib prefix="ora" uri="orataglib" %>
..

The error message I get in Tomcat is;

org.apache.jasper.JasperException: File "/ch7/orataglib" not found
org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:51)
org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:409)
org.apache.jasper.compiler.ErrorDispatcher.jspError(ErrorDispatcher.java:116)
org.apache.jasper.compiler.TagLibraryInfoImpl.<init>(TagLibraryInfoImpl.java:160)
org.apache.jasper.compiler.Parser.parseTaglibDirective(Parser.java:420)
org.apache.jasper.compiler.Parser.parseDirective(Parser.java:476)
org.apache.jasper.compiler.Parser.parseElements(Parser.java:1426)
org.apache.jasper.compiler.Parser.parse(Parser.java:133)
org.apache.jasper.compiler.ParserController.doParse(ParserController.java:215)
org.apache.jasper.compiler.ParserController.parse(ParserController.java:102)
org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:167)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:306)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:286)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:273)
org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:566)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:308)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:320)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)

NOTE: I HAVE NOT YET CREATED A WEB.XML file. could this be the cause of this? in the dos prompt it says:
WARNING: Internal Error: File /WEB-INF/web.xml not found
[ October 08, 2007: Message edited by: Chunnard Singh ]

[paritosh ranjan]

You are specifying URI in the tld file.So,mapping URI to a tld is not necessary if the URI is specified in the taglib and the tld is inside a jar file.So,if this tld is inside a jar file then the JSP engine will find it automatically;However,if the tld file is not in a jar file,then you will have to map the URI to a tld file in web.xml.

[paritosh ranjan]

If you still have some doubts then read "explicit mapping","implicit mapping" and "well known URI's",i hope this will clear out the doubts on this topic.

[Arvind Mahendra]

Hi paritosh. I was thinking the same thing that I had to add an entry in web.xml however the web.xml given by the author is as follows nowhere does it have an entry for the TLD file.

<?xml version="1.0" encoding="ISO-8859-1"?>
 
<web-app xmlns="http://java.sun.com/xml/ns/j2ee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee 
      [url=http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"]http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"[/url]
    version="2.4">
 
  <!-- Used by the JSTL I18N actions -->
  <context-param>
    <param-name>
      javax.servlet.jsp.jstl.fmt.fallbackLocale
    </param-name>
    <param-value>
      en
    </param-value>
  </context-param>
 
  <!-- Used by the JSTL database actions -->
  <context-param>
    <param-name>
      javax.servlet.jsp.jstl.sql.dataSource
    </param-name>
    <param-value>
      jdbc:mysql:///test,org.gjt.mm.mysql.Driver
    </param-value>
  </context-param>
 
  <!-- Used by the ResourceManagerListener in Chapter 19  -->
  <context-param>
    <param-name>driverClass</param-name>
    <param-value>
      org.gjt.mm.mysql.Driver
    </param-value>
  </context-param>
 
  <context-param>
    <param-name>jdbcURL</param-name>
    <param-value>
      jdbc:mysql:///test
    </param-value>
  </context-param>
 
  <!-- Filter and listener configurations for Chapter 19 -->
  <filter>
    <filter-name>accessControl</filter-name>
    <filter-class>
      com.ora.jsp.servlets.AccessControlFilter
    </filter-class>
    <init-param>
      <param-name>loginPage</param-name>
      <param-value>/ch19/login.jsp</param-value>
    </init-param>
  </filter>
 
  <filter-mapping>
    <filter-name>accessControl</filter-name>
    <url-pattern>/ch19/protected/*</url-pattern>
  </filter-mapping>
 
  <listener>
    <listener-class>
      com.ora.jsp.servlets.ResourceManagerListener
    </listener-class>
  </listener>
 
  <listener>
    <listener-class>
      com.ora.jsp.servlets.SessionCounterListener
    </listener-class>
  </listener>
 
  <!-- Servlet for showing JSP source. NOTE! Remove this in production -->
  <servlet>
    <servlet-name>jspSource</servlet-name>
    <servlet-class>JSPSourceServlet</servlet-class>
  </servlet>
 
  <servlet-mapping>
    <servlet-name>jspSource</servlet-name>
    <url-pattern>/jspSource/*</url-pattern>
  </servlet-mapping>
 
  <!-- Example servlets, see Chapter 19 -->
  <servlet>
    <servlet-name>helloWorld</servlet-name>
    <servlet-class>HelloWorld</servlet-class>
  </servlet>
 
  <servlet-mapping>
    <servlet-name>helloWorld</servlet-name>
    <url-pattern>/hello/*</url-pattern>
  </servlet-mapping>
 
  <servlet>
    <servlet-name>helloYou</servlet-name>
    <servlet-class>HelloYou</servlet-class>
  </servlet>
 
  <servlet-mapping>
    <servlet-name>helloYou</servlet-name>
    <url-pattern>/helloYou/*</url-pattern>
  </servlet-mapping>
 
  <servlet>
    <servlet-name>helloMIME</servlet-name>
    <servlet-class>HelloMIME</servlet-class>
  </servlet>
 
  <servlet-mapping>
    <servlet-name>helloMIME</servlet-name>
    <url-pattern>/helloMIME/*</url-pattern>
  </servlet-mapping>
 

  <!-- Struts Controller servlet, see Chapter 19 -->
  <servlet>
    <servlet-name>action</servlet-name>
    <servlet-class>org.apache.struts.action.ActionServlet</servlet-class>
    <load-on-startup>1</load-on-startup>
  </servlet>
 
  <servlet-mapping>
    <servlet-name>action</servlet-name>
    <url-pattern>*.do</url-pattern>
  </servlet-mapping>
 
  <!-- The Welcome File List -->
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
 
<!--
  Uncomment if you want all exceptions to be handled by the customized 
  error page.
  <error-page>
    <exception-type>java.lang.Throwable</exception-type>
    <location>/ch9/errorpage.jsp</location>
  </error-page>
-->
 
  <!-- 
    This resource reference is only used to test the JNDI config described 
    in Chapter 23. None of the examples use it.
  -->
  <resource-ref>
    <description>
      JNDI DataSource for example database
    </description>
    <res-ref-name>jdbc/Example</res-ref-name>
    <res-type>javax.sql.DataSource</res-type>
    <res-auth>Container</res-auth>
    <res-sharing-scope>Sharable</res-sharing-scope>
  </resource-ref>
 
  <!-- Security constraints for examples in Chapter 13 -->
  <security-constraint>
    <web-resource-collection>
      <web-resource-name>admin</web-resource-name>
      <url-pattern>/ch13/admin/*</url-pattern>
      <url-pattern>/ch13/search/delete.jsp</url-pattern>
    </web-resource-collection>
    <auth-constraint>
      <role-name>admin</role-name>
    </auth-constraint>
  </security-constraint>
 
  <security-constraint>
    <web-resource-collection>
      <web-resource-name>search</web-resource-name>
      <url-pattern>/ch13/search/*</url-pattern>
    </web-resource-collection>
    <auth-constraint>
      <role-name>admin</role-name>
      <role-name>user</role-name>
    </auth-constraint>
  </security-constraint>
 
  <login-config>
    <auth-method>BASIC</auth-method>
    <realm-name>ORA Examples</realm-name>
  </login-config>
 
  <security-role>
    <role-name>admin</role-name>
  </security-role>
  <security-role>
    <role-name>user</role-name>
  </security-role>
 
</web-app>

I will read the docs you have suggested. where can I find them?

[paritosh ranjan]

JSP.7.3.9 Well-Known URIs

A JSP container may �know of� some specific URIs and may provide alternate
implementations for the tag libraries described by these URIs, but the user must see
the behavior as that described by the required, portable tag library description
described by the URI.
A JSP container must always use the mapping specified for a URI in the
web.xml deployment descriptor if present. If the deployer wants to use the
platform-specific implementation of the well-known URI, the mapping for that
URI should be removed at deployment time.

I am not sure but the tld you are using looks like a well known uri i.e. URI which is already known to the container.

So,the mapping might not be needed as the container already knows about the well known uri's.

I read that mapping stuff in a book on scwcd by Hanumant Deshmukh.