taglib的问题？

Question

web.xml改成
<taglib>
       <taglib-uri>/mytags</taglib-uri>
       <taglib-location>/WEB-INF/jsp/
       mytaglib.tld</taglib-location>
    </taglib>然后jsp改成
<%@ taglib uri="/mytags" prefix="first" %>

Answer 1

同意楼上的
uri="/mytags"只要和web.xml中的<taglib-uri>/mytags</taglib-uri>
对应就可以了

Answer 2

to liad()在web.xml中
<taglib>
       <taglib-uri>/mytags</taglib-uri>
       <taglib-location>/WEB-INF/jsp/
       mytaglib.tld</taglib-location>
    </taglib>
应放在那个部分？我的web.xml为：?xml version="1.0" encoding="ISO-8859-1"?><!DOCTYPE web-app
    PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
    "http://java.sun.com/dtd/web-app_2_3.dtd"><web-app>    <display-name>Tomcat Examples</display-name>
    <description>
      Tomcat Example servlets and JSP pages.
    </description>    <!-- Define servlet-mapped and path-mapped example filters -->
    <filter>
        <filter-name>Servlet Mapped Filter</filter-name>
        <filter-class>filters.ExampleFilter</filter-class>
<init-param>
    <param-name>attribute</param-name>
    <param-value>filters.ExampleFilter.SERVLET_MAPPED</param-value>
</init-param>
    </filter>
    <filter>
        <filter-name>Path Mapped Filter</filter-name>
        <filter-class>filters.ExampleFilter</filter-class>
<init-param>
    <param-name>attribute</param-name>
    <param-value>filters.ExampleFilter.PATH_MAPPED</param-value>
</init-param>
    </filter>
    <filter>
        <filter-name>Request Dumper Filter</filter-name>
        <filter-class>filters.RequestDumperFilter</filter-class>
    </filter>    <!-- Example filter to set character encoding on each request -->
    <filter>
        <filter-name>Set Character Encoding</filter-name>
        <filter-class>filters.SetCharacterEncodingFilter</filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>EUC_JP</param-value>
        </init-param>
    </filter>    <filter>
        <filter-name>Compression Filter</filter-name>
        <filter-class>compressionFilters.CompressionFilter</filter-class>        <init-param>
          <param-name>compressionThreshold</param-name>
          <param-value>10</param-value>
        </init-param>
        <init-param>
          <param-name>debug</param-name>
          <param-value>0</param-value>
        </init-param>
    </filter>    <!-- Define filter mappings for the defined filters -->
    <filter-mapping>
        <filter-name>Servlet Mapped Filter</filter-name>
<servlet-name>invoker</servlet-name>
    </filter-mapping>
    <filter-mapping>
        <filter-name>Path Mapped Filter</filter-name>
<url-pattern>/servlet/*</url-pattern>
    </filter-mapping>
<!-- Example filter mapping to apply the "Set Character Encoding" filter
     to *all* requests processed by this web application -->
<!--
    <filter-mapping>
        <filter-name>Set Character Encoding</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
--><!--
    <filter-mapping>
      <filter-name>Compression Filter</filter-name>
      <url-pattern>/CompressionTest</url-pattern>
    </filter-mapping>
--><!--
    <filter-mapping>
        <filter-name>Request Dumper Filter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
-->    <!-- Define example application events listeners -->
    <listener>
        <listener-class>listeners.ContextListener</listener-class>
    </listener>
    <listener>
        <listener-class>listeners.SessionListener</listener-class>
    </listener>    <!-- Define servlets that are included in the example application -->    <servlet>
        <servlet-name>SendMailServlet</servlet-name>
        <servlet-class>SendMailServlet</servlet-class>
    </servlet>    <servlet>
        <servlet-name>
            snoop
        </servlet-name>
        <servlet-class>
            SnoopServlet
        </servlet-class>
<!--
        <init-param>
            <param-name>foo</param-name>
            <param-value>bar</param-value>
        </init-param>
-->
        <run-as>
            <description>Security role for anonymous access</description>
            <role-name>tomcat</role-name>
        </run-as>
    </servlet>    <servlet>
      <servlet-name>
          servletToJsp
      </servlet-name>
      <servlet-class>
          servletToJsp
      </servlet-class>
    </servlet>
        <servlet>
        <servlet-name>
            CompressionFilterTestServlet
        </servlet-name>
        <servlet-class>
            compressionFilters.CompressionFilterTestServlet
        </servlet-class>    </servlet>    <servlet-mapping>
        <servlet-name>invoker</servlet-name>
        <url-pattern>/servlet/*</url-pattern>
    </servlet-mapping>    <servlet-mapping>
        <servlet-name>
            CompressionFilterTestServlet
        </servlet-name>
        <url-pattern>
            /CompressionTest
        </url-pattern>
    </servlet-mapping>    <servlet-mapping>
        <servlet-name>SendMailServlet</servlet-name>
        <url-pattern>/SendMailServlet</url-pattern>
    </servlet-mapping>    <servlet-mapping>
        <servlet-name>
            snoop
        </servlet-name>
        <url-pattern>
            /snoop
        </url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>
            servletToJsp
        </servlet-name>
        <url-pattern>
            /servletToJsp
        </url-pattern>
    </servlet-mapping>    <taglib>
        <taglib-uri>
   http://jakarta.apache.org/tomcat/debug-taglib
        </taglib-uri>
        <taglib-location>
           /WEB-INF/jsp/debug-taglib.tld
        </taglib-location>
    </taglib>
   <taglib>
        <taglib-uri>
   http://jakarta.apache.org/tomcat/examples-taglib
        </taglib-uri>
        <taglib-location>
           /WEB-INF/jsp/example-taglib.tld
        </taglib-location>
    </taglib><taglib>
       <taglib-uri>/mytags</taglib-uri>
       <taglib-location>/WEB-INF/jsp/
       mytaglib.tld</taglib-location>
    </taglib>
    

Answer 3

<resource-ref>
      <res-ref-name>mail/Session</res-ref-name>
      <res-type>javax.mail.Session</res-type>
      <res-auth>Container</res-auth>
    </resource-ref>    <security-constraint>
      <display-name>Example Security Constraint</display-name>
      <web-resource-collection>
         <web-resource-name>Protected Area</web-resource-name>
 <!-- Define the context-relative URL(s) to be protected -->
         <url-pattern>/jsp/security/protected/*</url-pattern>
 <!-- If you list http methods, only those methods are protected -->
 <http-method>DELETE</http-method>
         <http-method>GET</http-method>
         <http-method>POST</http-method>
 <http-method>PUT</http-method>
      </web-resource-collection>
      <auth-constraint>
         <!-- Anyone with one of the listed roles may access this area -->
         <role-name>tomcat</role-name>
 <role-name>role1</role-name>
      </auth-constraint>
    </security-constraint>    <!-- Default login configuration uses form-based authentication -->
    <login-config>
      <auth-method>FORM</auth-method>
      <realm-name>Example Form-Based Authentication Area</realm-name>
      <form-login-config>
        <form-login-page>/jsp/security/protected/login.jsp</form-login-page>
        <form-error-page>/jsp/security/protected/error.jsp</form-error-page>
      </form-login-config>
    </login-config>    <!-- Security roles referenced by this web application -->
    <security-role>
      <role-name>role1</role-name>
    </security-role>
    <security-role>
      <role-name>tomcat</role-name>
    </security-role>    <!-- Environment entry examples -->
    <!--env-entry>
      <env-entry-description>
         The maximum number of tax exemptions allowed to be set.
      </env-entry-description>
      <env-entry-name>maxExemptions</env-entry-name>
      <env-entry-value>15</env-entry-value>
      <env-entry-type>java.lang.Integer</env-entry-type>
    </env-entry-->
    <env-entry>
      <env-entry-name>minExemptions</env-entry-name>
      <env-entry-value>1</env-entry-value>
      <env-entry-type>java.lang.Integer</env-entry-type>
    </env-entry>
    <env-entry>
      <env-entry-name>foo/name1</env-entry-name>
      <env-entry-value>value1</env-entry-value>
      <env-entry-type>java.lang.String</env-entry-type>
    </env-entry>
    <env-entry>
      <env-entry-name>foo/bar/name2</env-entry-name>
      <env-entry-value>true</env-entry-value>
      <env-entry-type>java.lang.Boolean</env-entry-type>
    </env-entry>
    <env-entry>
      <env-entry-name>name3</env-entry-name>
      <env-entry-value>1</env-entry-value>
      <env-entry-type>java.lang.Integer</env-entry-type>
    </env-entry>
    <env-entry>
      <env-entry-name>foo/name4</env-entry-name>
      <env-entry-value>10</env-entry-value>
      <env-entry-type>java.lang.Integer</env-entry-type>
    </env-entry>    <!-- EJB Reference -->
    <ejb-ref>
      <description>Example EJB Reference</description>
      <ejb-ref-name>ejb/Account</ejb-ref-name>
      <ejb-ref-type>Entity</ejb-ref-type>
      <home>com.mycompany.mypackage.AccountHome</home>
      <remote>com.mycompany.mypackage.Account</remote>
    </ejb-ref>    <!-- Local EJB Reference -->
    <ejb-local-ref>
      <description>Example Local EJB Reference</description>
      <ejb-ref-name>ejb/ProcessOrder</ejb-ref-name>
      <ejb-ref-type>Session</ejb-ref-type>
      <local-home>com.mycompany.mypackage.ProcessOrderHome</local-home>
      <local>com.mycompany.mypackage.ProcessOrder</local>
    </ejb-local-ref></web-app>
我在web.xml中所放的
<taglib>
       <taglib-uri>/mytags</taglib-uri>
       <taglib-location>/WEB-INF/jsp/
       mytaglib.tld</taglib-location>
    </taglib>
位置对吗？

Answer 4

你看看http://java.sun.com/dtd/web-app_2_3.dtd就知道taglib应该放在哪里了

Answer 5

你可以用XMLSPY来察看该dtd文件
web-app sequence of
icon 0 or 1 
display-name 0 or 1 
description 0 or 1 
distributable 0 or 1 
context-param 0 or more 
filter 0 or more 
filter-mapping 0 or more 
listener 0 or more 
servlet 0 or more 
servlet-mapping 0 or more 
session-config 0 or 1 
mime-mapping 0 or more 
welcome-file-list 0 or 1 
error-page 0 or more 
taglib 0 or more 
resource-env-ref 0 or more 
resource-ref 0 or more 
security-constraint 0 or more 
login-config 0 or 1 
security-role 0 or more 
env-entry 0 or more 
ejb-ref 0 or more 
ejb-local-ref 0 or more 

Answer 6

To liad()
我看了，没找到有用的信息，我现在的问题是：我用上面的web.xml 启动tomcat,运行jsp错误为type Status reportmessage /examples/jsp/hello.jspdescription The requested resource (/examples/jsp/hello.jsp) is not available.
我想这说所明了web.xml没配置好，我把web.xml中的：<taglib>
       <taglib-uri>/mytags</taglib-uri>
       <taglib-location>/WEB-INF/jsp/
       mytaglib.tld</taglib-location>
    </taglib>
 删除运行，jsp错误为：
type Exception reportmessage description The server encountered an internal error () that prevented it from fulfilling this request.exception org.apache.jasper.JasperException: File "/mytags" not found这说明了jsp页面从web.xml中没发现/mytags.我吧<taglib-uri>/mytags</taglib-uri>
       <taglib-location>/WEB-INF/jsp/
       mytaglib.tld</taglib-location>
    </taglib>
 加入web.xml中重起tomcat就出现前面的错误：type Status reportmessage /examples/jsp/hello.jspdescription The requested resource (/examples/jsp/hello.jsp) is not available
我想问题处在web.xml中 ，能指出错误吗？谢谢！！！！！

Answer 7

给你一个最简单的例子,来自《Professional JSP Tag Libraries》
// DateTag.java
package com.liad.jsptaglibs.date;import java.text.DateFormat;
import java.util.Date;
import java.util.Locale;import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspTagException;
import javax.servlet.jsp.tagext.TagSupport;/**
 * A custom tag that displays the current date.
 *
 * @author    Simon Brown
 */
public class DateTag extends TagSupport {  /**
   * Called when the starting tag is encountered.
   */
  public int doStartTag() throws JspException {    // get the locale of the client and create an appropriate date format
    Locale loc = pageContext.getRequest().getLocale();
    DateFormat df = DateFormat.getDateInstance(DateFormat.MEDIUM, loc);    try {
      // and write out the formatted date to the page
      pageContext.getOut().write(df.format(new Date()));
    } catch (java.io.IOException ioe) {
      throw new JspTagException(ioe.getMessage());
    }    // and skip evaluating the body of the tag (as there shouldn't be one)
    return SKIP_PAGE;
  }}simple.tld
==========
<?xml version="1.0" encoding="ISO-8859-1" ?> 
<!DOCTYPE taglib
  PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN"
  "http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd"><taglib>   <tlib-version>1.0</tlib-version> 
  <jsp-version>1.2</jsp-version>
  <short-name>simple</short-name>
  <description>Examples for the Simple Tags chapter</description>
  
  <tag> 
    <name>date</name> 
    <tag-class>com.liad.jsptaglibs.date.DateTag</tag-class>
    <body-content>empty</body-content>
    <description>Inserts the current date into the page</description> 
  </tag>
  
</taglib>web.xml
=======
<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE web-app PUBLIC '-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN' 'http://java.sun.com/dtd/web-app_2_3.dtd'><web-app>
  <display-name>Professional JSP Tag Libraries</display-name>
  <taglib>
    <taglib-uri>/simpleTaglib</taglib-uri>
    <taglib-location>/WEB-INF/tlds/simple.tld</taglib-location>
  </taglib>
</web-app>datetag.jsp
===========
<html>  <head>
    <title>Professional JSP Tag Libraries</title>
  </head>  <%@ taglib uri="/simpleTaglib" prefix="simple" %>  <body>    <h1>The date is <simple:date/></h1>  </body></html>

Answer 8

用dos命令tree /f获得的目录结构是
tagtest
│  datetag.jsp
│
└─WEB-INF
    │  web.xml
    │
    ├─classes
    │  └─com
    │      └─liad
    │          └─jsptaglibs
    │              └─date
    │                      DateTag.class
    │
    └─tlds
            simple.tld

Answer 9

To liad()
我按照你提供的例子，运行datetag.jsp
tomcat出现的错误还是：
type Status reportmessage /tagTestCenter/jsp/datetag.jspdescription The requested resource (/tagTestCenter/jsp/datetag.jsp) is not available.
--------------------------------------------------------------------------------
在dos用命令tree /f 显示如下：
tagTestCenter
├─jsp
│      DateTag.java
│      datetag.jsp
│
└─WEB-INF
    │  web.xml
    │
    ├─tlds
    │      simple.tld
    │
    └─classes
        └─com
            └─liad
                └─jsptaglibs
                    └─date
                            DateTag.class
我不知问题出在哪里？谢谢你的关照和帮助！！！！！