Jsp tag file例子以及说明(17)

[java] 
<%@ taglib prefix="tags" tagdir="/WEB-INF/tags" %> 
Your referer header: 
${header.referer}//从http协议中header获取referer，上一个http地址(从这里跳转到当前的地址) 
<br/> 
<tags:doBodyDemo>   //设置jspFragment为tag helper类 
  ${header.referer}//将header.referer的值通过jspFragment的dotag,在dotag回调invoke(out),放入到jspFragment(tag编译后的类)指定的变量 
</tags:doBodyDemo> 
<a href="viewReferer.jsp">View</a> the referer as a Session attribute. 

doBodyDemo.tag
[java] 
<jsp:doBody var="referer" 
scope="session"/>//转换out.tostring保存在session变量referer中 

 

viewReferer.jsp
[java] 
The Referer header of the previous page is 
${sessionScope.referer}//这是session中有referer变量，直接可以展示 

例子6 调用tag file并传入参数

powerTagTest.jsp
[java] 
//自定义标签，通过传入参数调用jspFragment.dotag 
<%@ taglib prefix="easy" tagdir="/WEB-INF/tags" %> 
2^3=<easy:power number="2" power="3"/> 

power.tag
[java]
<%-- Shows how to use attributes in a tag file --%>  
<%@ attribute name="number" required="true" description="base" %> 
<%@ attribute name="power" required="true" description="exponent" %> 
<%=Math.pow(Double.parseDouble(number), 
        Double.parseDouble(power))%>//通过传入的参数计算 

编译后的代码
powerTagTest_jsp.java
[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.Object page = this; 
  javax.servlet.jsp.JspWriter _jspx_out = null; 
  javax.servlet.jsp.PageContext _jspx_page_context = null; 
 
 
  try { 
    response.setContentType("text/html"); 
    pageContext = _jspxFactory.getPageContext(this, request, response, 
                null, true, 8192, true); 
    _jspx_page_context = pageContext;