简介

Jsp2.0后，实现tag的方式除了taglib(TLD)的方式外，还可以通过定义tag文件来代替taglib类。tag file一般放在/WEB-INF/tags目录或者其子目录,需要在jsp文件中指定uri。

参考

  例子来源

• http://today.java.net/pub/a/today/2003/11/14/tagfiles.html
• http://today.java.net/pub/a/today/2003/11/25/tagfiles.html

说明

注:jsp和tag file在Tomcat7下编译。

例子1 将tag file作为内容直接引入

       firstTagTest.jsp

<%@ page contentType="text/html; charset=UTF-8" %>
<%@ taglib prefix="easy" tagdir="/WEB-INF/tags" %>
Today is <easy:firstTag/> //包含tag，没有参数传递

firstTag.tag

//直接被firstTagTest.jsp引入编译为java/class文件
<%@ tag import="java.util.Date" import="java.text.DateFormat"%>
<%
  DateFormat dateFormat = DateFormat.getDateInstance(DateFormat.LONG);
  Date now = new Date(System.currentTimeMillis());
  out.println(dateFormat.format(now));
%>

     firstTag_tag.java

public void doTag() throws javax.servlet.jsp.JspException, java.io.IOException {
    javax.servlet.jsp.PageContext _jspx_page_context = (javax.servlet.jsp.PageContext)jspContext;
    javax.servlet.http.HttpServletRequest request = (javax.servlet.http.HttpServletRequest) _jspx_page_context.getRequest();
    javax.servlet.http.HttpServletResponse response = (javax.servlet.http.HttpServletResponse) _jspx_page_context.getResponse();
    javax.servlet.http.HttpSession session = _jspx_page_context.getSession();
    javax.servlet.ServletContext application = _jspx_page_context.getServletContext();
    javax.servlet.ServletConfig config = _jspx_page_context.getServletConfig();
    javax.servlet.jsp.JspWriter out = jspContext.getOut();
    _jspInit(config);
    jspContext.getELContext().putContext(javax.servlet.jsp.JspContext.class,jspContext);

    try {
      out.write('\r');
      out.write('\n');

  DateFormat dateFormat = DateFormat.getDateInstance(DateFormat.LONG);
  Date now = new Date(System.currentTimeMillis());
  out.println(dateFormat.format(now));

      out.write('\r');
      out.write('\n');
    } catch( java.lang.Throwable t ) {
      if( t instanceof javax.servlet.jsp.SkipPageException )
          throw (javax.servlet.jsp.SkipPageException) t;
      if( t instanceof java.io.IOException )
          throw (java.io.IOException) t;
      if( t instanceof java.lang.IllegalStateException )
          throw (java.lang.IllegalStateException) t;
      if( t instanceof javax.servlet.jsp.JspException )
          throw (javax.servlet.jsp.JspException) t;
      throw new javax.servlet.jsp.JspException(t);
    } finally {
      jspContext.getELContext().putContext(javax.servlet.jsp.JspContext.class,super.getJspContext());
      ((org.apache.jasper.runtime.JspContextWrapper) jspContext).syncEndTagFile();
    }
  }

firstTagTest_jsp.java

public void _jspService(final javax.servlet.http.HttpServletRequest request, final javax.servlet.http.HttpServletResponse response)
        throws java.io.IOException, javax.servlet.ServletException {

    final javax.servlet.jsp.PageContext pageContext;
    javax.servlet.http.HttpSession session = null;
    final javax.servlet.ServletContext application;
    final javax.servlet.ServletConfig config;
    javax.servlet.jsp.JspWriter out = null;
    final java.lang.